UX-08 2d review: action log reachable in status JSON, engaged peak row pinned, imported keys expanded

- status_payload() also returns the action log as `events`. The page
  does not render it. Some entries (a dropped inverter's reason, the peak
  guard's projection, unplaced watts) are written nowhere else, and DOCS
  still points installers at the action log.
- test_peakguard pins the engaged row's ordered pair (the battery's share,
  then the limit).
- test_messages expands setting keys named by constants imported from
  another app module, so the shown-text 30-word scan counts them.
- p1.py: 'A meter message could not be read'. DOCS glossary: control
  board in plain words, with the hardware in an installer note.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitea/infra-pin

@@ -0,0 +1,2 @@
+# The admin/goodwe commit CI tests against. Bump: set to the full SHA of admin/goodwe release/1.0 HEAD (README.md, "CI and the infra pin").
+7081df4276ad3cf788355b97a3b3f40ea28d72bd

.gitea/workflows/checks.yml

@@ -3,12 +3,35 @@
 # of real coverage including a wall-clock cadence test, and not one machine ever
 # ran them. Every merge here was a human reading a diff.
 #
-# ⚠️ NO `paths:` FILTER, AND ITS ABSENCE IS LOAD-BEARING. Branch protection on
-# release/1.0 requires the context `checks / unit (pull_request)`. Gitea leaves a
-# required context it never receives PENDING forever, so the moment this workflow
-# learns to sit a PR out, that PR becomes unmergeable. Condition a STEP if you
+# ⚠️ NO EVENT FILTER OF ANY KIND - NO `paths:`, AND SINCE CI-9 NO `branches:`
+# EITHER - AND THAT ABSENCE IS LOAD-BEARING. Branch protection on release/1.0
+# requires the context `checks / unit (pull_request)`. Condition a STEP if you
 # must; never the workflow.
 #
+# ⚠️ CI-01 WROTE THE REASON DOWN WRONG, AND THE WRONG REASON WAS THE SAFE-
+# SOUNDING ONE. It said an unreceived required context sits PENDING forever, so
+# a sat-out pull request becomes unmergeable - annoying, but fail-safe. That is
+# not what this Gitea does. MEASURED on Gitea 1.27.3, 2026-09-19, throwaway
+# PR #94: when a workflow exists but its event filter does not match, Gitea does
+# not stay silent. It POSTS the required context itself, with state `skipped`:
+#
+#   GET /api/v1/repos/admin/goodwe-addon/commits/<head sha>/statuses
+#     [{"status":"skipped","context":"checks / unit (pull_request)",
+#       "description":"Skipped","target_url":""}]      <- no run, no job, no url
+#
+#   GET /api/v1/repos/admin/goodwe-addon/commits/<head sha>/status
+#     {"state":"success","total_count":1}              <- the rollup LAUNDERS it
+#
+# and Gitea's merge gate accepts it. Same PR, same head sha, one status on it
+# and that status a skip, POST .../pulls/94/merge answered 409 `head out of
+# date` - the 409 being a deliberately wrong `head_commit_id` in the probe, i.e.
+# the request had ALREADY CLEARED BRANCH PROTECTION. The control, a required
+# context with no status at all, answered 405 `Not all required status checks
+# successful`. So the true failure mode is the exact inverse of the one written
+# here before: sitting a pull request out does not make it unmergeable, it makes
+# it MERGEABLE WITHOUT EVER BEING TESTED, and the badge says success while it
+# happens. Fail-open, not fail-closed. Do not reintroduce a filter here.
+#
 # ⚠️ THE RUNNER IS SHARED WITH THE OTHER REPO'S RIG. `goodwe-runner` on
 # 192.168.2.147 carries the labels `self-hosted` and `goodwe-rig` and is
 # registered `:host`, and it is the only runner there is - so this job wears the
@@ -23,9 +46,116 @@
 # that step; a green from this workflow is a claim about content that can land.
 name: checks
 
+# ⚠️ CI-9: `pull_request:` TAKES NO `branches:` LIST, ON PURPOSE. It used to
+# read `branches: [release/1.0, master]`, which meant a STACKED pull request -
+# one whose base is another feature branch rather than a release branch - did
+# not match, and so was skipped, laundered to `success`, and mergeable untested
+# by the mechanism described at the top of this file.
+#
+# ⚠️ AND RETARGETING DID NOT REPAIR IT, WHICH IS WHAT MADE THIS P1. The skip is
+# a COMMIT STATUS ON THE HEAD SHA, not a property of the pull request, so moving
+# the base afterwards leaves it exactly where it was. Observed live on PR #93
+# (2026-09-19): retargeted TEL-10 -> release/1.0, and the 10:05:00 `skipped`
+# stayed attached to head a6af332 with the rollup still reading success. It was
+# caught by a human who forced a real execution by reopening the pull request
+# (run 799, 10:56). Reproduced deliberately on throwaway PR #94: retargeted onto
+# a branch carrying a byte-identical copy of release/1.0's protection rule, and
+# the single `skipped` status survived the retarget unchanged - no new run, no
+# new status - and still cleared the gate.
+#
+# ⚠️ WHY NOT FIX THIS AT THE GATE INSTEAD, which would be the better place. It
+# cannot be done. Gitea's branch protection cannot express "this context must be
+# SUCCESS" as opposed to "this context must be PRESENT AND NOT FAILING". The
+# whole of its status-check vocabulary is two fields - `enable_status_check`
+# (bool) and `status_check_contexts` (a list of globs MATCHING CONTEXT NAMES) -
+# confirmed against this server's own schema at /swagger.v1.json, definitions
+# EditBranchProtectionOption and CreateBranchProtectionOption. There is no field
+# for the required STATE anywhere in either. The success/skip comparison lives
+# in Gitea's compiled code, so the only lever left is upstream of it: make sure
+# the context is never a skip in the first place. Hence this block.
+#
+# ⚠️ WHAT THIS COSTS, stated honestly, because it is a real trade. Every pull
+# request now runs the full suite, including the intermediate steps of a stack
+# that nobody intends to merge on its own. A run is ~8 minutes wall clock
+# (run 799: 7m55s) on a runner that is `capacity: 1` and shared with the other
+# repo's rig, so each extra run is ~8 minutes of slot that a rig campaign then
+# queues behind.
+#
+# SCALE OF THE NEW WORK, re-derived from the API and stated with its denominator,
+# because the first version of this paragraph had a made-up one. Counting the 93
+# pull requests that predate this ticket (#1..#93; CI-9's own #94..#98 excluded,
+# and note /pulls caps a page at 50, so this needs paging to see at all): 92 were
+# opened against release/1.0 and would have run anyway, and exactly ONE was
+# stacked - #2, TEL-01 -> SAFETY-04, closed unmerged, 2026-08-24. No pull request
+# has ever targeted `master`, so half the old filter was dead from the start.
+#
+# ⚠️ THAT 92 IS AN UPPER BOUND, NOT A CENSUS, and the reason is this very bug.
+# The API reports a pull request's CURRENT base, so one that was opened stacked
+# and later retargeted is recorded against its final base and is invisible here.
+# #93 is precisely that case - opened 2026-09-19T10:05:00 on TEL-10, retargeted,
+# merged into release/1.0 at 11:05:26 the same morning, under three hours before
+# CI-9 was opened - and it counts in the 92. So the true historical stacking rate
+# is somewhere above 1/93, and unmeasurable from here.
+#
+# The bill is therefore small today and grows with however much stacking the team
+# adopts. It is worth paying: the alternative is that the cheap case stays
+# untested and indistinguishable from the tested one.
+#
+# ⚠️ THIS DOES NOT CHANGE GITEA'S ACCEPTANCE OF A `skipped` REQUIRED CONTEXT -
+# that half is in its compiled code and is not reachable from this repository.
+# The CONSEQUENCE, though, is very largely closeable from here, and is closed:
+# after this edit there is nothing in this repository that produces a skip -
+# there is exactly one workflow file, it now has no event filter of any kind,
+# and the other candidate cause was MEASURED and is not one. The `guard the
+# trigger` step below then keeps it that way mechanically rather than by asking
+# the next editor to read this comment.
+#
+# ⚠️ READ THE BLIND SPOTS ON THAT STEP BEFORE TRUSTING THE SENTENCE ABOVE.
+# "Mechanically" holds only for a reintroduced filter that still names the
+# PR's own base. For blind spots 1 and 3 the defence IS this comment, because
+# the guard lives inside the workflow that a filter makes Gitea skip. Blind
+# spot 3 is the one that matters: a filter naming a branch THIS pull request
+# does not target is itself skipped, lands green and untested, and then every
+# subsequent pull request the filter DOES NOT NAME is skipped too. That is the
+# gate off, silently.
+#
+# ⚠️ THAT DIRECTION IS THE WHOLE POINT AND IT IS EASY TO WRITE BACKWARDS. A
+# pull request that MATCHES the filter still runs; it is the one the filter
+# excludes that Gitea sits out, reports `skipped`, and the rollup launders
+# into `success`. An earlier draft of this very clause said "matching it is
+# skipped", which is the inverse of the measurement and contradicted the
+# paragraph directly below.
+#
+# ⚠️ AND THE DANGEROUS ONE IS NOT `branches: [main]`, WHICH AT LEAST LOOKS
+# WRONG. It is `branches: [release/1.0]`, which looks like tightening onto the
+# protected branch and is what a careful person would write. Every day-to-day
+# pull request still runs and still goes green, so nothing appears broken -
+# and the only thing switched off is the `release/1.0` -> `master` release
+# PR, i.e. the one whose content reaches an installed system. SEC-2 made that
+# PR the mandated release path (docs/RELEASE.md), so this is now a live route
+# rather than a hypothetical one.
+#
+# Closing it needs a SECOND permanently unfiltered workflow posting its own
+# context, with that context added to the `status_check_contexts` of BOTH
+# `release/1.0` AND `master` - both carry the rule since SEC-2, and adding it
+# to one alone leaves the hole open on the other. A forge change, with the
+# owner.
+#
+# THE MEASUREMENT, because the obvious guess is wrong and was nearly written
+# here as fact. A skip-ci keyword in a commit message (`[skip ci]`, `[ci skip]`,
+# `[no ci]`, `[skip actions]`, `[actions skip]`) does NOT behave like a filter
+# miss. On throwaway PR #94, head b36effb, commit subject ending `[skip ci]`:
+#
+#   .../commits/b36effb/statuses   ->  []                  <- NO status, not a skip
+#   .../commits/b36effb/status     ->  {"state":"pending"} <- so the rollup is pending
+#   POST .../pulls/94/merge        ->  405 Not all required status checks successful
+#
+# i.e. skip-ci is FAIL-CLOSED - it withholds the context entirely, which is the
+# pending-forever behaviour CI-01's header wrongly attributed to a filter miss.
+# It blocks the merge rather than laundering it, so it needs no fix and no
+# app.ini change. Only the filter miss ever posted a `skipped`.
 on:
   pull_request:
-    branches: [release/1.0, master]
   workflow_dispatch:
 
 # ⚠️ NO `concurrency:` BLOCK, AND ITS ABSENCE IS AS LOAD-BEARING AS THE MISSING
@@ -156,8 +286,9 @@ jobs:
         run: |
           set -eu
           rm -rf "$WS" && mkdir -p "$WS/goodwe-addon" && cd "$WS/goodwe-addon"
-          git init -q .
-          git remote add origin "$(echo "$URL" | sed "s#://#://x-access-token:${TOKEN}@#")"
+          git init -q . && git remote add origin "$URL"
+          # Token as an env-set header: not in argv or .git/config (TOOL-9).
+          export GIT_CONFIG_COUNT=1 GIT_CONFIG_KEY_0=http.extraHeader GIT_CONFIG_VALUE_0="Authorization: token $TOKEN"
           if [ -n "$PRNUM" ]; then
             # Two fetches, not one, so that a failure to reach either ref fails
             # HERE with the ref in the message, rather than inside the merge
@@ -224,6 +355,165 @@ jobs:
             exit 1
           fi
 
+      # ⚠️ THE GUARD ON THE TRIGGER. THIS STEP EXISTS BECAUSE PROSE ALREADY
+      # FAILED IN THIS FILE, ONCE, FOR TWENTY DAYS.
+      #
+      # `git show 9c1a23328a` is CI-01's first commit. It shipped the header
+      # "⚠️ NO `paths:` FILTER, AND ITS ABSENCE IS LOAD-BEARING" and the line
+      # `branches: [release/1.0, master]` IN THE SAME COMMIT, EIGHTEEN LINES
+      # APART. The comment forbade one kind of event filter while the code
+      # directly above the job carried another, and nobody caught it through 84
+      # merges until the gate let a stacked pull request through. So the whole of
+      # CI-9's fix rests on an invariant - "checks.yml has no event filter" -
+      # that has already been silently violated in this exact file by the person
+      # who wrote the warning against violating it. A louder comment is not a
+      # remedy for that. A red step is.
+      #
+      # WHY THIS CAN WORK AT ALL, given CI-9 rejected the card's option 3 (a step
+      # that detects its own workflow having been skipped) as impossible. That
+      # option is impossible because a skipped workflow runs no steps, so there
+      # is nothing alive to notice. This is the different, tractable case: it
+      # fires on the pull request that REINTRODUCES a filter, and it does so
+      # whenever the filter being reintroduced STILL NAMES THAT PULL REQUEST'S
+      # OWN BASE - the ordinary case, because a filter put back by hand names
+      # the release branch people are actually targeting. The edit then has to
+      # get past this step before it can start causing skips. It is a ratchet,
+      # not a skip detector.
+      #
+      # ⚠️ AND IT IS THE HEAD'S WORKFLOW THAT DECIDES WHETHER ANYTHING RUNS, NOT
+      # THE BASE'S. An earlier draft of this comment claimed the reintroducing
+      # pull request "is still graded by the unfiltered workflow which is on the
+      # base today". That was wrong, it contradicted the checkout step's own note
+      # a few lines below, and the error was not cosmetic: it made this step
+      # sound like an unconditional ratchet, which is exactly the false comfort
+      # CI-9 exists to stamp out. MEASURED on PR #101 - head carrying a filter
+      # that excludes the base, base carrying the unfiltered workflow - and the
+      # result was no run at all, the context posted `skipped`, the rollup
+      # reading `success`, and the gate CLEARED (409). Gitea takes the workflow
+      # file from refs/pull/<n>/head, so a head that filters itself out is simply
+      # never graded, and nothing on the base can reach out and stop it. That is
+      # what blind spot 3 below is made of.
+      #
+      # WHAT IT INSPECTS is the MERGED tree in $WS - the content that would
+      # actually land on the base - not the branch tip and not the copy of this
+      # file that Gitea used to decide whether to run. Those are three different
+      # trees here (see the long note on the checkout step) and only the merged
+      # one is the thing being authorised.
+      #
+      # ⚠️ THREE ACKNOWLEDGED BLIND SPOTS. NOT ONE OF THEM IS CLOSEABLE FROM
+      # INSIDE THIS FILE, and the reason is the same in all three: each is a case
+      # where THIS WORKFLOW IS ITSELF THE THING THAT GETS SKIPPED, and a guard
+      # that lives inside a skipped workflow does not run. Closing them needs a
+      # SECOND, permanently unfiltered workflow whose own context is added to
+      # release/1.0's `status_check_contexts`, so that something survives to
+      # report when this file is sat out. That is a forge change and the
+      # repository owner's decision; it is being put to them separately and is
+      # deliberately NOT held as a blocker on CI-9.
+      #
+      #   1. A reintroduced `paths:` filter crafted to exclude the reintroducing
+      #      pull request's OWN diff would skip that pull request, so this step
+      #      would not run to object to it.
+      #
+      #   2. An edit that lands on a feature branch through a stacked pull
+      #      request is graded by the HEAD's workflow, so a filter already
+      #      present in the head hides the edit from this step - until that
+      #      branch is proposed for release/1.0, where (unless it is case 3) the
+      #      base matches the reintroduced filter and this step runs and bites.
+      #      Caught at the release boundary, which is the boundary that matters.
+      #
+      #   3. ⚠️ THE WORST OF THE THREE, AND WORSE THAN BOTH OF THE OTHERS PUT
+      #      TOGETHER: a reintroduced `branches:` filter that simply DOES NOT
+      #      NAME THE BASE escapes this step entirely, because the pull request
+      #      carrying it is itself skipped. It takes no craft and no malice to
+      #      write - `branches: [main]` copied out of a GitHub template, or a
+      #      tidy-up to `[master]`, a branch that NO pull request in this
+      #      repository's history has ever targeted - and it arrives as a
+      #      skipped, laundered, untested merge into release/1.0.
+      #
+      #      What makes it categorically worse is what happens the moment after.
+      #      Once that file is ON release/1.0, every subsequent pull request is
+      #      graded against it and every one of them is skipped too. This is not
+      #      the stacked case leaking through a crack; it is the gate off
+      #      completely, for everything, silently, with every badge green. The
+      #      only thing standing between the repository and that state today is
+      #      a human reading this file - which is precisely the kind of defence
+      #      this step exists because it has already failed once (9c1a23328a).
+      #
+      # It is deliberately a FAILURE and not a warning: a warning would leave
+      # the required context green, which is the precise defect CI-9 is about.
+      - name: guard the trigger - refuse a checks.yml that has regained an event filter
+        run: |
+          set -eu
+          f="$WS/goodwe-addon/.gitea/workflows/checks.yml"
+          test -f "$f" || { echo "checks.yml is missing from the merged tree."; exit 1; }
+          # Walk the top-level `on:` block of the MERGED file. Full-line comments
+          # at column 0 are skipped outright - this file's own prose quotes
+          # `paths:` and `branches:` many times and must not trip its own guard -
+          # and an inline `#` is trimmed from any line that is kept.
+          bad=$(awk '
+            function scan(t) {
+              sub(/#.*/, "", t)
+              if (t ~ /(^|[^A-Za-z0-9_-])(branches|branches-ignore|paths|paths-ignore|tags|tags-ignore|types)[[:space:]]*:/)
+                return 1
+              return 0
+            }
+            /^[[:space:]]*#/ { next }
+            /^("on"|'"'"'on'"'"'|on)[[:space:]]*:/ {
+              inon = 1
+              rest = $0; sub(/^[^:]*:/, "", rest)
+              if (scan(rest)) print NR ": " $0
+              next
+            }
+            inon == 1 {
+              if ($0 ~ /^[[:space:]]*$/) next
+              if ($0 ~ /^[[:space:]]/) { if (scan($0)) print NR ": " $0; next }
+              inon = 0
+            }
+          ' "$f")
+          if [ -n "$bad" ]; then
+            echo "REFUSED: checks.yml has regained an event filter in its \`on:\` block."
+            echo "$bad"
+            echo
+            echo "  A filter means some pull request stops matching this workflow. Gitea does"
+            echo "  not stay silent about a workflow it sits out - it posts the required context"
+            echo "  \`checks / unit (pull_request)\` itself with state \`skipped\`, the combined"
+            echo "  status rolls that up as \`success\`, and the merge gate ACCEPTS it. That is"
+            echo "  CI-9: a pull request merged on a workflow that never ran a step. It was"
+            echo "  reproduced by merging PR #96 for real through a protected branch."
+            echo
+            echo "  Branch protection cannot save you here - it can require that a context is"
+            echo "  PRESENT, never that it is SUCCESS - so the filter is the whole defence."
+            echo "  If you genuinely need to narrow what runs, condition a STEP, never the"
+            echo "  workflow. See the \`on:\` block's comments for the measurements."
+            exit 1
+          fi
+          echo "OK: the \`on:\` block of the merged checks.yml carries no event filter."
+
+      # CI-12: the infra repo at the ONE pinned commit in .gitea/infra-pin (read
+      # from the merged tree), as the sibling test_freeze.py looks for. Any
+      # failure here fails the job; the tests step below refuses the stub.
+      - name: check out admin/goodwe at the pin in .gitea/infra-pin
+        env:
+          URL: ${{ github.server_url }}/admin/goodwe.git
+          # Read access to admin/goodwe only; this job's own token cannot see it.
+          TOKEN: ${{ secrets.INFRA_READ_TOKEN }}
+        run: |
+          set -eu
+          # `|| true`: under pipefail a missing or comment-only pin would skip the FAIL line (TOOL-9).
+          PIN=$(grep -v '^#' "$WS/goodwe-addon/.gitea/infra-pin" | tr -d '[:space:]') || true
+          echo "$PIN" | grep -Eq '^[0-9a-f]{40}$' || { echo "FAIL: .gitea/infra-pin holds '$PIN', not a full 40-hex SHA."; exit 1; }
+          test -n "$TOKEN" || { echo "FAIL: secret INFRA_READ_TOKEN is not available to this run (a fork PR?)."; exit 1; }
+          rm -rf "$WS/goodwe" && mkdir -p "$WS/goodwe" && cd "$WS/goodwe"
+          git init -q .
+          # The token goes in a header via env: not in argv, and not in .git/config,
+          # which is mounted into the tests' container and outlives a failed job.
+          GIT_CONFIG_COUNT=1 GIT_CONFIG_KEY_0=http.extraHeader GIT_CONFIG_VALUE_0="Authorization: token $TOKEN" \
+            git fetch -q "$URL" "$PIN" || { echo "FAIL: could not fetch admin/goodwe at $PIN."; exit 1; }
+          git -c advice.detachedHead=false checkout -qf FETCH_HEAD
+          test "$(git rev-parse HEAD)" = "$PIN"
+          test -f sim/hwsim.py || { echo "FAIL: admin/goodwe@$PIN has no sim/hwsim.py."; exit 1; }
+          echo "infra: admin/goodwe @ $(git log --oneline -1)"
+
       - name: build the test image (shipped deps, from apk - see .gitea/ci/Dockerfile)
         run: |
           set -eu
@@ -244,16 +534,9 @@ jobs:
       # shorter timeout - a 60 s limit was tried during CI-01 and reported
       # exactly the false hang the docstring predicts.
       #
-      # ⚠️ WHAT THIS RUN DOES NOT COVER, stated because a pass here would
-      # otherwise over-claim. test_freeze.py's third section wants the infra
-      # repo's `sim/hwsim.py` to drive a real HTTP meter through the real
-      # transport. admin/goodwe is PRIVATE (checked via the API) and this
-      # workflow's GITHUB_TOKEN is minted for THIS repository only, so hwsim is
-      # absent here and `find_hwsim()` returns None. The rest of the file runs
-      # and passes. It does so SILENTLY - the file prints nothing to say the
-      # hwsim section was skipped - so "test_freeze.py: PASS" below is a weaker
-      # claim than it looks. That belongs to whoever owns test_freeze.py next;
-      # naming it here is the least this gate can do about it.
+      # test_freeze.py part 3 runs against the real `sim/hwsim.py` from the
+      # checkout above; GOODWE_REQUIRE_HWSIM=1 makes it fail rather than use its
+      # stub (CI-12). Lines a test prints with a `CI: ` prefix are echoed on PASS.
       # ⚠️ PYTHONDONTWRITEBYTECODE=1 IS BELT AND BRACES, NOT A FIX FOR A LIVE
       # HOLE. TEST-15 measured this runner's actual exposure and found none: the
       # checkout below is bind mounted `:ro`, so the interpreter physically
@@ -269,7 +552,7 @@ jobs:
       - name: the add-on's own tests
         run: |
           set -eu
-          docker run --rm -e PYTHONDONTWRITEBYTECODE=1 -v "$WS:/w:ro" goodwe-addon-checks:1 sh -eu -c '
+          docker run --rm -e PYTHONDONTWRITEBYTECODE=1 -e GOODWE_REQUIRE_HWSIM=1 -v "$WS:/w:ro" goodwe-addon-checks:1 sh -eu -c '
             cd /w/goodwe-addon/goodwe_controller
             set -- test_*.py
             if [ "$1" = "test_*.py" ]; then
@@ -282,6 +565,7 @@ jobs:
               start=$(date +%s)
               if python3 "$f" > /tmp/out 2>&1; then
                 echo "PASS  $f  ($(( $(date +%s) - start ))s)"
+                grep "^CI: " /tmp/out || true
               else
                 echo "FAIL  $f  ($(( $(date +%s) - start ))s)"
                 tail -40 /tmp/out

.gitea/workflows/infra-pin.yml

@@ -0,0 +1,46 @@
+# CI-12: goes red when admin/goodwe release/1.0 has moved past .gitea/infra-pin.
+# It runs on add-on activity only; admin/goodwe's own `addon-pin` workflow
+# covers a move of release/1.0 there. Deliberately NOT a required check: it
+# reports; `checks / unit` stays the only gate. How to bump: README.md,
+# "CI and the infra pin".
+name: infra-pin
+
+on:
+  pull_request:
+  push:
+    branches: [release/1.0]
+
+jobs:
+  fresh:
+    runs-on: [self-hosted, goodwe-rig]
+    timeout-minutes: 30   # seconds of work; the rest is queueing for the shared slot
+    steps:
+      - name: compare .gitea/infra-pin with admin/goodwe release/1.0
+        env:
+          SELF: ${{ github.server_url }}/${{ github.repository }}.git
+          INFRA: ${{ github.server_url }}/admin/goodwe.git
+          TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          INFRA_TOKEN: ${{ secrets.INFRA_READ_TOKEN }}   # admin/goodwe is private
+        run: |
+          set -eu
+          D=$(mktemp -d) && trap 'cd / && rm -rf "$D"' EXIT && cd "$D"
+          git init -q .
+          # The pin of the commit this event is about (the PR head, or the push).
+          # Token as an env-set header: not in argv or .git/config (TOOL-9).
+          GIT_CONFIG_COUNT=1 GIT_CONFIG_KEY_0=http.extraHeader GIT_CONFIG_VALUE_0="Authorization: token $TOKEN" \
+            git fetch -q --depth 1 "$SELF" "$GITHUB_SHA" || { echo "FAIL: could not fetch $GITHUB_SHA here."; exit 1; }
+          # `|| true`: under the runner's pipefail a missing or comment-only pin
+          # would stop here on git's error instead of the FAIL line below (TOOL-9).
+          PIN=$(git show FETCH_HEAD:.gitea/infra-pin | grep -v '^#' | tr -d '[:space:]') || true
+          test -n "$PIN" || { echo "FAIL: .gitea/infra-pin is missing at $GITHUB_SHA, or holds only comments."; exit 1; }
+          test -n "$INFRA_TOKEN" || { echo "FAIL: secret INFRA_READ_TOKEN is not available to this run (a fork PR?)."; exit 1; }
+          # Header via env, as in checks.yml: the token stays out of argv.
+          HEAD=$(GIT_CONFIG_COUNT=1 GIT_CONFIG_KEY_0=http.extraHeader GIT_CONFIG_VALUE_0="Authorization: token $INFRA_TOKEN" \
+            git ls-remote "$INFRA" refs/heads/release/1.0 | cut -f1) || true
+          test -n "$HEAD" || { echo "FAIL: could not read admin/goodwe release/1.0."; exit 1; }
+          if [ "$PIN" != "$HEAD" ]; then
+            echo "STALE: .gitea/infra-pin is $PIN but admin/goodwe release/1.0 is $HEAD."
+            echo "       Test against $HEAD and bump the pin (README.md, \"CI and the infra pin\")."
+            exit 1
+          fi
+          echo "OK: .gitea/infra-pin $PIN is admin/goodwe release/1.0 HEAD."

FIELD-GUIDE.md

@@ -4,6 +4,10 @@ The guide technicians carry is the PDF:
 
 **`docs/GoodWe-RS485-Field-Guide.pdf`** — 10 pages, A4, print it double-sided.
 
+⚠️ **Outdated: it is v0.1.0.** Its `slew_w` row is corrected in `build_guide.py`
+and `field-guide.html`, but the PDF has not been rebuilt (see below). Where the
+guide disagrees with `goodwe_controller/DOCS.md`, DOCS.md wins.
+
 It covers, in the order the work is done: pre-visit checks, hardware, firmware,
 add-on install and configuration, how to read the Web UI, the six commissioning
 gates, the e-stop (and the statement a site without one must sign), proving a
@@ -18,7 +22,8 @@ copy cannot drift from the PDF someone is holding in a cellar.
 python3 docs/build_guide.py     # regenerates field-guide.html and the PDF
 ```
 
-Requires Chrome or Chromium (used headless for print-to-PDF). Screenshots live
+Requires Chrome or Chromium (used headless for print-to-PDF); `CHROME` in the
+script is a Windows path, so edit it on any other machine. Screenshots live
 in `docs/img/` and are base64-embedded, so `field-guide.html` is standalone.
 
 ⚠️ **Every section must stay under the A4 printable height** (1039 px at 96 dpi

README.md

@@ -30,9 +30,11 @@ goodwe_controller/         the add-on
                            returns, run against its own release image
 firmware/goodwe-master.yaml  ESPHome config for the T-CAN485
 estop/rs485_log.py           optional RS485 e-stop / bus witness
-docs/GoodWe-RS485-Field-Guide.pdf  the guide techs carry (10pp, A4)
+docs/GoodWe-RS485-Field-Guide.pdf  the guide techs carry (10pp, A4; outdated)
 docs/build_guide.py          its single source - rebuilds the HTML and PDF
 FIELD-GUIDE.md             how to edit and rebuild the guide
+docs/RELEASE.md            how a change reaches the battery - `master` is
+                           protected, releases go via PR from `release/1.0`
 ```
 
 **Picking this up after a break? Read `HANDOVER.md` first** — current state,
@@ -48,6 +50,9 @@ https://gittea.kammenstraatha.duckdns.org/admin/goodwe-addon
 
 then install **GoodWe RS485 Controller**.
 
+Then turn on **Watchdog** on the add-on's Info tab — see
+[Before you start](goodwe_controller/DOCS.md#before-you-start).
+
 ⚠️ **The repository must be PUBLIC for this to work.** Home Assistant clones it
 anonymously; against a private repo the store shows nothing and gives no useful
 error. If it must stay private, install locally instead: copy
@@ -77,8 +82,8 @@ machine itself dying:
 2. **Wind-down before firmware updates** — 0 W written before the update starts.
 3. **RS485 e-stop (optional)** — writes 0 W after 30 s of total bus silence.
 
-Sites sold without the e-stop must have the acknowledgement in `FIELD-GUIDE.md`
-§10 signed.
+Sites sold without the e-stop must have the client acknowledgement in the field
+guide (Step 7b) signed.
 
 ## Development
 
@@ -100,6 +105,12 @@ has the mechanism, the measurement, and what the flags do not do. They are not u
 each assertion corresponds to a rule whose absence produced an observed failure
 on real hardware, and the comments in `control.py` say which.
 
+### CI and the infra pin
+
+CI (`.gitea/workflows/checks.yml`) runs every `test_*.py`, with `admin/goodwe` checked out next to this repo at the commit in `.gitea/infra-pin`, so `test_freeze.py` grades against the real `sim/hwsim.py`. If that checkout fails, the job fails. The local stub is used only in local runs, and it prints `STUB USED` when it is.
+The pin tracks `admin/goodwe` **release/1.0**, not master. Two non-required checks go red when release/1.0 has moved past the pin: `infra-pin / fresh` here, on any add-on PR or push to release/1.0, and `addon-pin / fresh` in `admin/goodwe`, on every push to its release/1.0. Nothing re-runs `addon-pin` after a bump, so it stays red on that admin/goodwe commit; `infra-pin / fresh` green on the bump is the all-clear.
+**Bump the pin** whenever either is red. Set `.gitea/infra-pin` to the new release/1.0 SHA (`git ls-remote <gitea>/admin/goodwe.git refs/heads/release/1.0`) in a PR, and let `checks / unit` grade the tests against it. CI reads `admin/goodwe` with the Actions secret `INFRA_READ_TOKEN`.
+
 ## Compatibility
 
 **Check the serial number, not the model name.** Characters 6-8 of the serial are

STYLE.md

@@ -0,0 +1,63 @@
+# STYLE.md - how user-facing text is written (UX-08)
+
+This applies to everything a home owner or installer reads: notifications, phone pushes, the add-on page, refusals, add-on log lines at WARNING and above, and the names and descriptions of options. It is enforced by `goodwe_controller/test_messages.py`. Its allowlist is empty since phase 2d and its cap is 0: a new string that breaks the rule fails the test.
+
+## 1. Shape
+- **Title**: at most 5 everyday words. It says what is wrong ("Meter reading may be stuck"). No "GoodWe:" prefix, no full stop.
+- **Body**: **one sentence** of at most 25 words, saying what happened and what to do. A **red alarm** may use up to **3 sentences** (70 words, each sentence at most 30 words), so that no action a person must take is lost.
+- **Details**: the last line links to the add-on documentation and names the section with the rest: `Details: add-on documentation, section "<title>" under Notifications.` Background, figures, reason codes and history go there or into the log, never into the body.
+- **Status row**: one sentence of at most 15 words. A **red** row may use up to 3 sentences (30 words), like a red alarm. It shows the live numbers the reader acts on and never an HA entity id. **Banner**: at most 12 words. **Refusal**: at most 30 words, naming the setting by its label and then its key, as `messages.setting()` writes it: “Inverter rating” (max_w), or “Inverter rating” for inverter-b (inverters.max_w) for one inverter in the list. **Option name**: at most 6 words, not counting the group prefix. **Option description**: at most 30 words. Where a value comes from belongs in DOCS.md.
+- **Log line** (WARNING/ERROR): one line, at most 25 words, with the numbers that matter. The reasoning goes on a DEBUG line. Log lines stay in English and are not translated. A reason text a line quotes (`%s`) keeps its own codes, because that is the evidence an installer searches for.
+- **Refusal length is counted as shown**: a setting placeholder counts as its label and key, and the long cases are driven through the validator (`test_messages.py` part 3).
+- **Event line** under the buttons: the plain words of `messages.hint()`, like a green row. The add-on's own action log stays technical and is not shown on the page. Installers read it as `events` in the `status` JSON.
+- **Sentences**: one idea each, active voice, present tense, with nothing nested in brackets and no semicolons (a semicolon is a second sentence in disguise). These translate well into Dutch and French.
+
+## 2. Numbers
+Use a number only if it helps the reader act, for example the peak limit, or what was asked and what was sent in a fault report. Write it the way `app/messages.py` does: `5 000 W`, `20 %`, `10 minutes`, `14:05`.
+
+## 3. Severity
+Severity is shown by the title and the colour, never by CAPITALS or by words like "BUG SIGNAL".
+
+| Level | Colour | When |
+|---|---|---|
+| alarm | red | Control stopped, money or energy lost now, a fault, or a person must act now. Up to 3 sentences. |
+| warning | orange | Control is still running, but something needs a look. 1 sentence. |
+| info | grey | No action needed. 1 sentence. |
+| resolved | green | An earlier alarm or warning has cleared. 1 sentence. |
+
+A rewrite never changes an alarm's severity, `notification_id` or cadence.
+
+## 4. Words - the same word for the same thing everywhere
+A setting is named by its label in `translations/en.yaml`, in quotes when it sits mid-sentence (“Inverter rating”). The words below match those labels. If a label changes, change it here and in `app/messages.py` in the same change.
+
+| Say | Not |
+|---|---|
+| the add-on (who decides), control (what it does: "start control", "Control: last ran …") | controller, loop, planner |
+| battery | pack, BMS pack |
+| inverter, or its name | unit, device, actuator |
+| meter | P1 feed, telegram |
+| peak limit / this month's peak | ceiling, capaciteitstarief, billed quarter |
+| 15-minute period | quarter |
+| battery level (setting: “Battery level entity”) | SoC, state of charge, charge level |
+| battery cut-out level, or cut-out level next to "battery" (setting: “Battery cut-out level”) | BMS floor, `bms_soc_floor` |
+| peak reserve (setting: “Peak reserve”) | `peak_soc_floor`, EMS floor, "peak guard will not discharge below" |
+| “Inverter rating” (the setting) | `max_w`, rail, inverter rating as a fact about the hardware |
+| solar production, solar entity (settings: “Solar production entity”, “Solar production entities, per inverter”, “Reversed-sign solar entities”) | PV, reversed-sign list, single sensor setting |
+| “Where the meter reading comes from” | meter source |
+| “Grid power entity”; entity for any Home Assistant sensor a setting points at | grid power sensor, sensor setting |
+| draw the battery down, give power | discharge, discharging |
+| control is stopped / every inverter is set to 0 W | failsafe, trip, latch, parked |
+| safety stop (a stop that only starting control clears) | failsafe latch |
+| software fault | BUG SIGNAL |
+| control board | master, ESP32 |
+| power request, what the add-on asks | command, setpoint (on the page) |
+| the power went the wrong way | sign disagreement, command and meter point opposite ways |
+| check for inverters working against each other | circulating power check |
+| month peak, 15-minute periods measured | billed quarter, banked, soft limit, open block |
+| shadow mode | a mode that makes every decision but commands 0 W. The name is kept. In shadow mode a text says what the add-on **would** send, never that it sent it. |
+
+**Banned in titles and bodies** (the test fails on them): SAFETY-/TARIFF-/TEL-/CFG-/FW-/HW-nn and other card ids, integrator, anti-windup, windup, clamp, clamped, saturated, BUG SIGNAL, latch, latched, arbiter, allocator, register, `0x…`, layer 1/2/3, heartbeat, watchdog, telegram, ACK, CRC, OTA, Modbus, planner, `§n`, file names, IP addresses, option keys in snake_case, **HA entity ids**, and runs of 2 or more CAPITALISED words.
+
+HA entity ids are allowed only in refusals and validator messages, where the installer has to find that entity. They are never allowed in alarms or status rows.
+
+**Glossary.** DOCS.md "Words used on this page" explains, once, the words a home owner meets without context: control board, isolator, Developer Tools, shadow mode, safety stop, peak limit, peak guard, peak reserve and cut-out level. A home-owner text may use them without explaining them again. Card ids stay out of DOCS.md headings: they go on a *For installers* line under the heading.

docs/RELEASE.md

@@ -0,0 +1,116 @@
+# Releasing — how a change reaches the battery
+
+`master` is the **default branch**, and the default branch is what the Home
+Assistant Supervisor clones when it installs or updates this add-on. Whatever
+sits on `master` is what runs on a real 5 kW inverter. Treat a push to `master`
+as a deployment, because that is what it is.
+
+---
+
+## 1. `master` is protected — releases go through a pull request
+
+Until 2026-09-23 `master` had **no protection of any kind**. Every gate this
+repo built (CI-01, CI-9) sat on `release/1.0`, the branch that does *not* ship.
+On 2026-09-22 version 0.10.1 went straight onto `master` — no pull request, no
+CI run, no reviewer — and it succeeded (commit `0f14c2a`, the only commit on
+`master` that carries no `(#NN)` merge suffix). SEC-2 closed that.
+
+**The release path is now:**
+
+1. Merge the work into `release/1.0` as usual, via a pull request that goes
+   green. Bump `version:` in `goodwe_controller/config.yaml` on that branch —
+   the Supervisor keys the built image by `version:`, so without a bump nothing
+   is offered and nothing changes.
+2. Open a pull request **`release/1.0` → `master`**. Do not push to `master`;
+   it will be refused by the pre-receive hook:
+
+   ```
+   remote: error: Not allowed to push to protected branch master
+   ! [remote rejected] ... (pre-receive hook declined)
+   ```
+
+3. Wait for `checks / unit (pull_request)` to go **green** on that pull request.
+   The workflow in `.gitea/workflows/checks.yml` carries **no `branches:`
+   filter**, so a `master` base matches and a real run happens — verified on
+   throwaway PR #107 (base `master`), which queued a genuine run.
+
+   ⚠️ Green means green. A `skipped` status is laundered into a `success`
+   rollup by this Gitea and the merge gate accepts it — see the long note at
+   the top of `.gitea/workflows/checks.yml`. Never add an event filter there.
+
+4. Merge the pull request. `required_approvals` is **0**, so a green check is
+   the whole gate; there is no second pair of eyes unless someone asks for one.
+
+5. **Reload the store.** Merging to `master` does not, by itself, offer the
+   update. The Supervisor only sees the new version after:
+
+   ```bash
+   ssh root@192.168.2.158 "ha store reload && ha addons update local_goodwe_controller"
+   ```
+
+   Until `ha store reload` runs, the add-on page still shows the old version
+   and the release looks like it did nothing.
+
+Note that `release/1.0` is normally an *ancestor* of `master` between releases,
+so a `release/1.0 → master` pull request is empty until new commits land on
+`release/1.0`. That is expected; it means there is nothing to release yet.
+
+---
+
+## 2. Branch protection — before and after SEC-2
+
+Forge is Gitea at `192.168.2.147:3000`, repo `admin/goodwe-addon`. Read it back
+with `GET /api/v1/repos/admin/goodwe-addon/branch_protections`.
+
+**Before (2026-09-23):**
+
+| branch | protected | status check required | context | approvals |
+|---|---|---|---|---|
+| `master` (default) | **no rule at all** | — | — | — |
+| `release/1.0` | yes | yes | `checks / unit (pull_request)` | 0 |
+
+**After:**
+
+| branch | protected | status check required | context | approvals |
+|---|---|---|---|---|
+| `master` (default) | yes | yes | `checks / unit (pull_request)` | 0 |
+| `release/1.0` | yes (unchanged) | yes | `checks / unit (pull_request)` | 0 |
+
+Both rules are otherwise identical: `enable_push: false`,
+`enable_force_push: false`, `block_admin_merge_override: true`, no whitelists,
+no file patterns. `required_approvals` stays at **0** on purpose — raising it
+would block the review agent from merging, and nobody asked for it.
+
+The default branch was **not** changed. Changing it would change what the
+Supervisor clones, which is a different decision from this one.
+
+### How the gate was proven to actually bite
+
+A protection rule on this forge can *appear* satisfied while having checked
+nothing, so the rule was tested rather than trusted. The discriminator is a
+merge `POST` carrying a deliberately wrong `head_commit_id`: Gitea evaluates
+branch protection *before* it checks the head, so
+
+* `409 head out of date` → the request **cleared** protection;
+* `405 Not all required status checks successful` → protection **refused** it.
+
+Read the *message*, not just the code: `405` is also returned as
+`Please try again later` for a pull request with **no commits**, which has
+nothing to do with protection. An empty pull request on an unprotected base
+gives that same `405` (verified, throwaway PR #110), so an empty
+`release/1.0 → master` reports it too.
+
+Validated against a control on an unprotected base (PR #106), which answered
+`409` while its check was still pending — i.e. protection was no obstacle
+there. On `master` (PR #107) the same probe answered `405` while pending, and
+`409` once the check was genuinely green. A direct `git push` to `master` was
+rejected by the pre-receive hook with `master`'s SHA unmoved.
+
+---
+
+## 3. Rolling back
+
+There is no force-push escape hatch: `enable_force_push` is `false` on both
+branches. To undo a bad release, land a revert on `release/1.0`, bump the
+version again, and take it through §1. The `/addons/` rollback for the
+reference install is in `HANDOVER.md`.

docs/build_guide.py

@@ -95,7 +95,7 @@ figcaption { font-size:9pt; color:#5b6169; margin-top:1.2mm; }
 <div class="page" id="p1">
   <div class="hdr">
     <div><h1>GoodWe RS485 Controller</h1>
-         <div class="sub">Field installation &amp; commissioning guide — v0.1.0</div></div>
+         <div class="sub">Field installation &amp; commissioning guide — v0.1.0, <b>outdated</b>: where it disagrees with DOCS.md, DOCS.md wins</div></div>
     <small>Installer copy</small>
   </div>
 
@@ -503,7 +503,7 @@ figcaption { font-size:9pt; color:#5b6169; margin-top:1.2mm; }
   <table>
     <tr><th style="width:30mm">Setting</th><th style="width:16mm">Value</th><th>Reason</th></tr>
     <tr><td><code>gain</code></td><td>0.6</td><td>Inverter needs 3–6 s to settle (1.4 s dead time, 94 % by 3.3 s) against a ~5 s cycle. <b>At the limit — do not raise</b></td></tr>
-    <tr><td><code>slew_w</code></td><td>1000</td><td>Most of a correction in the first cycle without running far ahead of the hardware</td></tr>
+    <tr><td><code>slew_w</code></td><td>0</td><td>0 follows the rail (<code>max_w</code>&nbsp;/&nbsp;9). A faster fixed value is <b>refused at startup</b> (SAFETY-39) — see DOCS.md</td></tr>
     <tr><td><code>deadband_w</code></td><td>15</td><td>Measured residual: mean 15.4 W, max 27 W. At 10 W the command never rests</td></tr>
     <tr><td><code>saturation_w</code> / <code>cycles</code></td><td>500 / 3</td><td>Divergence = inverter at a limit → magnitude may fall, never rise. <b>The 3-cycle term is essential</b>: tested instantly it fires on every large correction</td></tr>
     <tr><td><code>step_w</code></td><td>10</td><td>Register is 1 W but response lands on a ~17.6 W ladder. Finer is meaningless</td></tr>

docs/field-guide.html

@@ -60,7 +60,7 @@ figcaption { font-size:9pt; color:#5b6169; margin-top:1.2mm; }
 <div class="page" id="p1">
   <div class="hdr">
     <div><h1>GoodWe RS485 Controller</h1>
-         <div class="sub">Field installation &amp; commissioning guide — v0.1.0</div></div>
+         <div class="sub">Field installation &amp; commissioning guide — v0.1.0, <b>outdated</b>: where it disagrees with DOCS.md, DOCS.md wins</div></div>
     <small>Installer copy</small>
   </div>
 
@@ -468,7 +468,7 @@ figcaption { font-size:9pt; color:#5b6169; margin-top:1.2mm; }
   <table>
     <tr><th style="width:30mm">Setting</th><th style="width:16mm">Value</th><th>Reason</th></tr>
     <tr><td><code>gain</code></td><td>0.6</td><td>Inverter needs 3–6 s to settle (1.4 s dead time, 94 % by 3.3 s) against a ~5 s cycle. <b>At the limit — do not raise</b></td></tr>
-    <tr><td><code>slew_w</code></td><td>1000</td><td>Most of a correction in the first cycle without running far ahead of the hardware</td></tr>
+    <tr><td><code>slew_w</code></td><td>0</td><td>0 follows the rail (<code>max_w</code>&nbsp;/&nbsp;9). A faster fixed value is <b>refused at startup</b> (SAFETY-39) — see DOCS.md</td></tr>
     <tr><td><code>deadband_w</code></td><td>15</td><td>Measured residual: mean 15.4 W, max 27 W. At 10 W the command never rests</td></tr>
     <tr><td><code>saturation_w</code> / <code>cycles</code></td><td>500 / 3</td><td>Divergence = inverter at a limit → magnitude may fall, never rise. <b>The 3-cycle term is essential</b>: tested instantly it fires on every large correction</td></tr>
     <tr><td><code>step_w</code></td><td>10</td><td>Register is 1 W but response lands on a ~17.6 W ladder. Finer is meaningless</td></tr>

goodwe_controller/DECISIONS/SAFETY-10-shadow-mode.md

@@ -0,0 +1,406 @@
+# SAFETY-10 — shadow mode, and why "default-on" is not `true`
+
+**Status:** decided and implemented on branch `SAFETY-10`.
+⚠️ **AMENDED BY SAFETY-47, and three of the claims below were false when this
+was merged.** §5's "the strategies are unaffected" exemption, §4's peak-guard
+row and §6's evidence table are corrected in place and each correction is
+marked. The amendments are marked rather than rewritten silently, because what
+this card believed is part of why the defect shipped. See
+`DECISIONS/SAFETY-47-what-a-shadow-run-can-show.md`.
+**Card:** SAFETY-10 — *"Shadow mode (default-on, log-only decisions)"*.
+**Nothing here reached the inverter.** No deployment, no `ha addons update`, no
+contact with 192.168.2.158 or 192.168.2.221. Everything below was measured in
+the CI image and on TEST-23 stage 3's closed-loop rig.
+
+---
+
+## 0. The four things a reader should take away
+
+1. **"Default-on" is delivered as `auto`, not as `true`, and the difference is
+   an install that is regulating a real battery today.** The Supervisor
+   composes an add-on's options as *its defaults, overlaid with the stored user
+   options*, so a new key with a new default reaches **every existing install**
+   on the next update. A boolean `shadow_mode: true` would silently stop the
+   reference site. §1.
+2. **Shadow mode WRITES. It writes 0 W, on the ordinary heartbeat, through the
+   ordinary single writer.** "Commands nothing" implemented as "stops writing"
+   would leave the inverter latched on whatever was standing — it has no meter
+   timeout — and would put the ESP32 into a tripped stale-input watchdog for
+   the whole run. §2.
+3. **The sign watchdogs are inert, and that was the decision that had to be got
+   right.** Fed the shadow decision they would trip within `sign_disagree_s`
+   and **latch a trip that survives into live operation and a restart**. §4.
+4. **The loop leg's shadow decision is one slew step, not a trajectory, and
+   that is a real limitation of this feature.** §5.
+5. ⚠️ **SAFETY-47: and neither is anything else that depends on the plant
+   answering back. A shadow run cannot surface a closed-loop defect at all**,
+   by the same construction that makes it safe — the battery is held at 0 W, so
+   every measured input describes a plant that did not respond. Of the three
+   defects §"WHAT DEFECT THIS PREVENTS" was written for, exactly one —
+   TARIFF-14's wrong quarter-hour — is visible from a shadow run. §5, §6.
+
+---
+
+## 1. The default
+
+### The literal reading, and what it costs
+
+`config.yaml`'s `options:` block **is** the default. There is exactly one of it,
+and HA's Supervisor resolves an add-on's effective options as
+
+```
+{**config.yaml options, **the stored user options}
+```
+
+A key that has never been stored therefore takes the file's value — on a fresh
+install and on an install that has been running for months, identically. There
+is **no mechanism in the add-on options system** by which one key can default
+differently for the two. So the card's title, taken at face value, is:
+
+> the next `ha addons update` stops the battery at the reference site, and the
+> only symptom is a battery that has stopped doing anything.
+
+That is strictly worse than every defect shadow mode exists to catch. It is
+refused.
+
+### What was shipped instead
+
+`shadow_mode` is a three-valued `list(auto|on|off)` defaulting to `"auto"`:
+
+| value | resolves to |
+|---|---|
+| `off` | live |
+| `on` | shadow, always |
+| `auto` | shadow **while control is stopped**; live once it is started |
+
+`auto` reads `Controller.auto` — the persisted start/stop state, which a fresh
+install takes from `auto_start` and which the *Start / stop control* button
+moves. No new persisted state, no migration, no guess:
+
+* a **fresh** install ships `auto_start: false`, has no stored `auto` key, and
+  therefore comes up **in shadow mode**. It observes a day of decisions before
+  it is ever allowed to command anything. That is the card's intent, delivered
+  where it is safe;
+* an install that is **controlling** is started, so `auto` resolves to live and
+  **not one watt changes**;
+* an install that is **stopped** keeps its actuator at 0 W exactly as before —
+  the same number, from the same writer, on the same heartbeat. What changes is
+  what the status page and the action log **say**, and that the decision path
+  now runs and is recorded.
+
+⚠️ **Under `auto`, pressing Start leaves shadow mode.** That is the point of
+`auto`: the button means "control the battery". An operator who wants the
+decisions recorded *while the loop runs* — the configuration this card exists
+to make possible — sets `on` explicitly, and cannot reach it by accident.
+
+⚠️ **An unrecognised value resolves to SHADOW, and is REFUSED at startup.**
+`shadow.mode()` fails toward inaction; `validate.py` rule 11 refuses the value
+by name so the reinterpretation is never silent. A typo is not a decision, and
+an install silently left in shadow mode commands nothing indefinitely while its
+status page calmly explains that this is intentional.
+
+---
+
+## 2. "Commands nothing" is a number, not a silence
+
+The inverter holds its last command **forever** — `HANDOVER.md` §6 says so, and
+`firmware/goodwe-master.yaml`'s header records what it cost when a controller
+stopped refreshing: *"Illusmart went silent mid-command and the inverter held
++5000 W for 113 s"*. `firmware/goodwe-master.yaml` states the contract that follows — *"HA
+must now REWRITE the setpoint every ~10 s even when the value has not
+changed"* — because without a refresh, **"stale" and "steady" are the same
+thing on the wire**.
+
+So shadow mode holds the actuator at `shadow.WIRE_W` = **0.0 W**, refreshed on
+the ordinary heartbeat. Two consequences were weighed and are recorded:
+
+* **it is not silence.** A shadow mode that stopped writing would leave the
+  standing command up until the ESP32's 30 s watchdog noticed — and at a site
+  with no such board, forever;
+* **it does not use an alarm as a mode.** Letting that watchdog trip for the
+  duration of a shadow run teaches the operator that `wd_tripped` is normal,
+  which is exactly the training that makes it useless when the add-on has
+  actually died.
+
+### It is not a second writer
+
+SAFETY-28's rule is one actuator, one writer. Shadow mode files **no claim**,
+owns **no transport**, and calls nothing in `hass.py`. It is a **substitution**
+inside `Controller._write_unit()` — the single choke point every write in this
+add-on already reaches, including the heartbeat, the stop button, `shutdown()`
+and `maint_abort()` — in exactly the form of the three substitutions above it
+(non-finite → 0 W, unauthorised → 0 W, clamped → the rating).
+
+It is the **last** of them. Below SAFETY-28's gate and below SAFETY-03's clamp,
+so both still grade the number the decision path actually produced, and a
+shadow run can report *"it would have hit the rating here"*.
+
+---
+
+## 3. What the run records
+
+| surface | what it carries |
+|---|---|
+| status banner | `SHADOW MODE - the battery is NOT being controlled...`, **first in the cascade**, amber — red, with the latch named, if one is standing |
+| status row `Shadow mode` | which rung decided, the watts it **would have commanded on this cycle**, where the inverter actually is, and `Resolution.explain()` — plus, when a measured billed quarter sized those watts, SAFETY-47's caveat saying so (`shadow.SIZED_FROM_METER`) |
+| status row `Commanded` | `0 W` — the truth, which the row above reconciles with the `Why` row below it |
+| action log | one line when shadow mode comes on; one line per **change of decision** (winner, rounded watts, or SAFETY-47's caveat state), carrying the arbiter's own sentence and the same caveat the row carries — `shadow.log_line()` is the one sentence both read |
+| MQTT | `status: shadow`, its own value, below `failsafe` |
+
+The action log is **edge**-logged, not level-logged: the log holds 40 rows, and
+a line per cycle would flush the context of the run's own findings inside four
+minutes at the 15 s cycle floor.
+
+---
+
+## 4. The failsafes, one by one
+
+| failsafe | in shadow mode | why |
+|---|---|---|
+| SAFETY-02/30 sign watchdogs | **INERT** | They grade `Inverter.standing_w()` — what this controller has standing on the wire — and shadow mode holds that at 0 W, so they cannot arm. ⚠️ Fed the shadow decision instead they would disagree with a meter that never saw it and **latch a trip that survives into live operation and a restart**: shadow mode would manufacture the failsafe it exists to help debug. ⚠️ **Two rungs hold it there** — `last_write` (the wire gate) and `inv.target` (the re-seed) — which is MUTATION.md's masking shape, so the mutation that reproduces the hazard defeats both as a pair (M6). Driven singly, dropping the re-seed does not reproduce it at all — measured |
+| SAFETY-03 clamp | **OBSERVES** | Runs on the decision, sets `clamp_last`, logs every engagement. Changes no command |
+| SAFETY-28 write gate | **OBSERVES** | Same placement, same reason: the question is who chose the number |
+| SAFETY-18 meter freeze | **OBSERVES**, unchanged | It takes no action live either; both halves of its conjunction are as true in shadow |
+| SAFETY-07/24/25 peak guard | **OBSERVES, AND SEES ONLY THE HOUSE** | Level-triggered, unlatched, files its claim as usual, so the recorded decision is the real one *for this meter*. ⚠️ **AMENDED BY SAFETY-47.** This row used to end "SAFETY-45's limit cycle is visible from a shadow run, which is the point". It is not: every term of `wanted = batt_w + excess` is measured, and in shadow mode the battery contributes nothing to either. Measured on the rig, same hour, same unsized code — **410 of 720 cycles engaged live, 0 of 720 in shadow** |
+| SAFETY-31 circulation | **OBSERVES AND MAY LATCH** | Its evidence is *measured* power. Packs pushing against each other while all are told 0 W is a real fault |
+| SAFETY-42 delivery | **OBSERVES AND MAY LATCH** | Same, against a share that is 0 W |
+| operator stop | **SUPPRESSED AS A CLAIM, ENFORCED AT THE WIRE** | The one deliberate change. Its `P_SAFETY` 0 W claim out-ranks everything, so leaving it in makes the recorded decision `"stopped"` on every cycle and the run answers the wrong question. The actuator ends at the same number either way, and the wire substitution is **strictly stronger**: a claim can be out-ranked, and it cannot |
+| inputs missing, non-finite, allocator refusal, arbiter contradiction | **UNCHANGED** | All resolve to 0 W, which is what the wire gets anyway |
+
+⚠️ **A latch that is already up stays up.** Nothing here clears one. The shadow
+banner **names** any standing latch and goes red for it, because a latch that is
+up while the controller is inert is up the moment it stops being inert.
+
+⚠️ **Maintenance is not in that table because shadow mode does not touch it.**
+The state machines are ticked on every cycle whether control is started or not,
+so a stopped install already runs them against a battery that does not move.
+Shadow mode inherits that, unchanged and unimproved. Recorded here rather than
+quietly fixed under another card's name.
+
+---
+
+## 5. The limitation, stated rather than discovered later
+
+`Controller._shadow_settle()` re-seeds the carried command (`self.target` and
+each `inv.target`) to `WIRE_W` at the **end** of every shadow cycle — after
+every in-cycle guard has read the decision. Three machines read that value as a
+statement about the **hardware**: the loop's `prev_w` and integrator,
+`standing_w()`, and SAFETY-42's share comparison. Re-seeded, they track reality,
+and **the exit is safe by construction** — the carried command already equals
+the standing one, so the first live cycle slews from 0 W like any other.
+
+⚠️ **The cost is real.** The loop's `prev_w` is therefore 0 W on every shadow
+cycle, so the loop leg's recorded decision is **one slew step from the standing
+command** and stays there. A shadow run answers *"what would this controller
+command NOW, from where the plant really is"* — a true statement about the
+present — and **not** *"what trajectory would it have followed"*. The trajectory
+is a closed-loop property, it did not happen, and reporting it would be a
+simulation of a plant that does not exist; three cycles in, such a number
+describes nothing.
+
+⚠️ **AMENDED BY SAFETY-47 — THE PARAGRAPH THAT STOOD HERE WAS THE DEFECT.**
+It read:
+
+> The strategies are unaffected: arbitrage, the peak guard and maintenance all
+> file `SET` claims at a fixed power from level-triggered inputs. That is why
+> the three defects this card was written for — SAFETY-45's 28 onsets an hour,
+> TARIFF-14's wrong quarter-hour, SAFETY-46's ceiling churn — are all visible
+> from a shadow run, and the loop's ramp is not.
+
+It was true until **SAFETY-45 merged, one commit before this card**. That
+change makes the buy leg `min(asked, headroom)` with
+
+```
+headroom = (900 / remaining) x (ceiling - projected)
+```
+
+and `projected` reads the **open quarter's accumulator** — the meter — which is
+a function of what the battery did earlier in that same quarter. The strategy
+is closed-loop, and the loop's one-slew-step limitation above is not a special
+case of anything: **it is the general case**, and the limitation is the whole
+feature's, not the loop leg's.
+
+**The correct statement, and it is now graded rather than asserted:**
+
+> A shadow run cannot surface a **closed-loop** defect — one whose stimulus is
+> the plant's response to the controller — because the battery is held at 0 W
+> and there is no response to be the stimulus. **Which** hour a strategy picks
+> and **why** are unaffected, because the clock and the price series are not
+> functions of the battery. **How hard** it trades is not.
+
+Of the three defects this card was written for:
+
+| | visible from a shadow run? | measured |
+|---|---|---|
+| SAFETY-45's limit cycle | **no** | 28 charge onsets live, **1** in shadow; grid −455.5 … +3200.0 W live, **flat at the 1200 W house** in shadow; guard engaged 410/720 live, **0/720** in shadow |
+| SAFETY-46's SoC churn | **no** | the SoC moves **0.000000000 pp** in a shadow run. No SoC limit can be *reached* in one |
+| TARIFF-14's wrong quarter-hour | **yes**, and it is the one | which hour, at what price, clearing what spread: identical live and shadow on **720 of 720** charging cycles, at a binding cap |
+
+Graded in `test_arbitrage.py` part **3d** — the same closed loop part 3c uses,
+run once live and once in shadow — and the loop leg's own limitation stays
+named in `test_watchdog.py` part 10 as `RECORDED LIMITATION`.
+
+---
+
+## 6. How "nothing reaches the inverter" is graded
+
+**Not on a flag.** A check that asserted `Controller.shadow` would pass on a
+build in which the flag is set and the substitution is deleted — which is
+exactly mutation **M1**.
+
+`test_clamp.py` part 8 drives the **shipped** `Controller.cycle()` and the
+shipped heartbeat against a recording Home Assistant stub, and asserts on what
+reached `set_number()`:
+
+* **the precondition first** — the same stimulus with `shadow_mode: off` puts
+  30 non-zero writes on the wire, the largest 5000 W. MUTATION.md habit 4: a
+  check whose data cannot reach the failure it names is decoration;
+* then `set(writes) == {0.0}`, **and** that there were 26 of them — a check
+  that only said "no non-zero write" would pass on the silent build too;
+* entry and exit are measured on `inv.last_write` — what the inverter is
+  latched on, updated only on an **accepted** write — either side of the
+  boundary, against the same run that never entered shadow mode.
+
+The closed-loop half is `/home/homelab/s10-mut/shadowloop.py` on TEST-23 stage
+3's rig: the same hour, twice, against `plantsim.Plant` through the firmware's
+own frame encoder.
+
+⚠️ **SUPERSEDED BY SAFETY-47 — THE TABLE THAT STOOD HERE COULD NEVER HAVE GONE
+RED, FOR TWO INDEPENDENT REASONS.** It read `arb_power_w` −2000 W *"identical"*,
+`arb_reason` *"identical, verbatim"*, arbiter winner *"identical"*, and
+concluded *"the decision happened, at the same instant, for the same reason, at
+the same signed power — and the battery did not move."* The battery half is
+true and is unchanged. The **decision** half was decoration:
+
+1. **the fixture is `peak_cap_w: 15000` against a 350 W house**, so the
+   capacity guard never engages and SAFETY-45's sizing is in the run and inert.
+   The harness's own comment says so — *"at this scenario's `peak_cap_w: 15000`
+   it is not binding anyway"* — which is MUTATION.md habit 4 written down
+   beside the check it disables;
+2. **every identity row reads the FIRST charging sample.** At `elapsed = 0`
+   the projection *is* the held level, so the two runs agree to the float there
+   **even at a cap that does bind**. Measured: closing reason (1) alone leaves
+   that comparison passing.
+
+Both had to be closed. Re-taken below at **`peak_cap_w` 1500 / house 1200 /
+`max_w` 2000**, one hour at a 5 s cycle, **across the whole run** — harness
+`/home/homelab/s47-mut/shadowloop47.py`, same rig, same three transcribed
+lines.
+
+| | live | shadow |
+|---|---|---|
+| grid | 1224.1 … 1506.0 W — **held up at the ceiling** | **1200.0 W flat = the house, exactly** |
+| SoC | 50.000019 → **51.856789 %** | 50.000000 → **50.000000 %** |
+| `ARBITRAGE_CHARGE` cycles | 720 / 720 | **720 / 720** |
+| first charging cycle, `arb_power_w` | −300.0000 W | **identical — and this is why the old table passed** |
+| `arb_power_w`, **whole run** | −307.799 … −299.930 W | **−2000.000 … −300.000 W** |
+| …cycles where the two differ | — | **716 of 720** |
+| `arb_reason`, whole run | the strategy's own sentence | **differs on 719 of 720** |
+| measured charging headroom | 299.93 … 307.80 W | **300.0 … 54 000.0 W** |
+| final recorded command | **−302.4 W** | **−2000.0 W — 6.61× the live figure** |
+| price / spread / which hour | | **identical on 720 of 720** |
+| arbiter winner | `arbitrage` | **identical** |
+
+**What the re-taken table says.** The decision still *happens*, at the same
+instant, on the same hour, at the same price, for the same *kind* of reason,
+and the battery still does not move — those were the card's real claims and
+they hold. What does **not** hold is that the decision is the *same decision*:
+its **size** is a function of a meter the battery never moved, and at this cap
+the recorded figure is 6.61× what a live controller commands. 54 000 W of
+"headroom" under a 1500 W ceiling is `900/remaining` multiplying a gap the
+battery never closed.
+
+⚠️ **And the SoC row is the second half of it.** 0.000000000 pp of movement is
+not a curiosity: it is the proof that **no SoC-limit behaviour is reachable
+from a shadow run at all**, which §5 used to promise.
+
+SAFETY-47 puts the caveat on both surfaces that carry the number and narrows
+the three documents' claims; `test_arbitrage.py` part 3d is the CI-side grader
+so this class cannot recur.
+
+⚠️ **Three lines of each harness are a TRANSCRIPTION and are marked as one.**
+`priceloop.Rig` has no `_write_unit()`, no clamp and no failsafe machine
+(divergence 2 of its README), so the substitution's **placement** is
+transcribed there. The shipped placement is graded by `test_clamp.py` part 8,
+which drives the real `Controller`. ⚠️ **And the rig's transcribed cycle
+predates SAFETY-45**: `arbitrage.decide()` gained a required
+`charge_headroom_w` after `478ba93`, and the harness supplies it from the
+**shipped** `peakguard.charge_headroom_w()` reading the **shipped** peak
+decision rather than from a constant, so SAFETY-45 stays in the run.
+
+---
+
+## 7. The mutation battery — 22 mutations, no survivors
+
+Harness: `/home/homelab/s10-mut/run.py`, backups beside it. Each run restores
+from backup, purges `__pycache__` **on the host**, and grades through the CI
+image with the tree bind-mounted `:ro`, so the interpreter cannot write a cache
+into the tree under test (TEST-15). The full table is in the branch report;
+one per new behaviour, including **M1** (the substitution deleted — a write
+escapes), **M2** (it returns instead of substituting — the inverter is left
+latched), **M3** (it moves above SAFETY-28 and SAFETY-03 — the observers go
+blind), **M8** (`auto` resolves to shadow unconditionally — the literal
+default-on that stops the live install), **M12** (the stop claim is filed in
+shadow — every recorded decision reads `stopped`), **M21** (the substitution
+and the re-seed together) and **M22** (the re-seed moved one line earlier —
+SAFETY-18 grades a 0 W no decision produced and goes permanently blind).
+
+⚠️ **Two findings from driving it, both of the kind MUTATION.md says to expect.**
+
+* **M2 first came back a SURVIVOR and was not one.** The "stop writing
+  altogether" build left `inv.last_write` as `None`, the check did `float()` on
+  it, and the section died with a `TypeError` — grading none of the checks
+  after it and reporting **zero reds**, which reads exactly like a survivor.
+  That is FCST-06's shape. The fixture now hands `None` back and names it as
+  its own check; M2 is red on three.
+* **M6 had to become a PAIR, and only the battery said so.** `standing_w()`
+  prefers `last_write` — the 0.0 W the wire gate accepted — and falls back to
+  `inv.target`, which the re-seed also holds at 0.0. Either rung alone keeps
+  the detector inert, so dropping the re-seed **singly** came back red on the
+  limitation check and on **nothing about the latch**: the hazard it names was
+  not reproduced. TEST-16's rule with a new name on it.
+* **M7/M8/M9/M19 had to MOVE SUITES.** They defeat `shadow.engaged()`, and a
+  defeated default stops `test_clamp.py` part 3's wired run reaching the wire
+  at all — aborting the file with an `IndexError` before part 8 is graded. The
+  red count there was a lower bound naming the saturation freeze. The mode
+  table now lives in `test_validate.py`, which drives no Controller.
+* **`shadow_would_w = float(self.target)` is an EQUIVALENT mutation and was
+  measured as one.** `_shadow_settle()` runs before the re-seed, so at that
+  line `self.target` **is** `resolution.target_w`. It is recorded as equivalent
+  rather than reported as a survivor, and the non-equivalent form of the same
+  defect — the record becoming the **wire** — is driven instead.
+
+### The table
+
+Each row: the mutation, the file, the byte delta, the suite it was graded in,
+and how many **named** checks went red. `⚠️` marks a row whose run did not
+reach the end of its file, so its count is a **lower bound** (MUTATION.md).
+
+| # | mutation | file | Δ | suite | reds |
+|---|---|---|---|---|---|
+| M1 | **a write escapes** — the substitution deleted | `main.py` | −6 B | clamp | 5 |
+| M2 | **silence instead of 0 W** — it returns rather than substituting | `main.py` | −15 B | clamp | 3 |
+| M3 | **the observers go blind** — it moves above SAFETY-28 and SAFETY-03 | `main.py` | +58 B | clamp | 1 |
+| M4 | the site re-seed dropped — the exit resumes from a fiction | `main.py` | −36 B | clamp | 3 |
+| M5 | the per-unit re-seed dropped | `main.py` | −22 B | clamp | 1 |
+| M6 | **PAIRED**: `standing_w()` reads the target **and** the re-seed dropped — the sign latch that survives into live operation | `inverter.py` + `main.py` | −170 B | watchdog | 3 |
+| M7 | `auto` inverted — shadow while started, live while stopped | `shadow.py` | +2 B | validate | 4 |
+| M8 | **default-on for everyone** — `auto` always shadow; the literal reading that stops the live install | `shadow.py` | −15 B | validate | 2 |
+| M9 | an unreadable value resolves to LIVE instead of shadow | `shadow.py` | +1 B | validate | 1 |
+| M10 | `validate.py` stops refusing an unknown value | `shadow.py` | −9 B | validate | 9 |
+| M11 | the loop leg gated on `auto` alone again — the decision path stops running | `main.py` | −17 B | clamp | 1 |
+| M12 | the stop claim filed in shadow — every decision reads `stopped` | `main.py` | −20 B | clamp | 1 |
+| M13 | the banner goes green while nothing is commanded | `shadow.py` | −2 B | clamp | 1 |
+| M14 | the banner loses the standing latch | `shadow.py` | −2 B | clamp | 1 |
+| M15 | the row renders the standing command instead of the decision | `shadow.py` | −8 B | clamp | 1 |
+| M16 ⚠️ | the row disappears when live | `main.py` | +43 B | clamp | 1 |
+| M17 | the record becomes the wire | `main.py` | −6 B | clamp | 7 |
+| M18 | level-logged — the 40-row action log floods | `main.py` | −23 B | clamp | 1 |
+| M19 | the two rungs render identically (masking) | `shadow.py` | +22 B | validate | 1 |
+| M20 | the shipped default moves to `off` in `config.yaml` alone | `config.yaml` | −1 B | defaults_pin | 1 |
+| M21 | **PAIRED**: the substitution **and** the re-seed deleted together | `main.py` | −103 B | clamp | 10 |
+| M22 | the re-seed moved one line earlier — SAFETY-18 grades a 0 W no decision produced and goes permanently blind | `main.py` | +40 B | clamp | 1 |
+
+**Survivors: none.** ⚠️ **M17's `+0 B`-adjacent sibling** —
+`shadow_would_w = float(self.target)` — is recorded in §7 as **equivalent**
+rather than counted here.

goodwe_controller/DECISIONS/SAFETY-39-slew-against-the-rail.md

@@ -187,6 +187,23 @@ over-absorption. So the rig does not choose the number — **the constraint
 chooses it, and the rig says what the constraint does and does not buy.** That
 is the same relationship the 2026-08-22 table had to its own three columns.
 
+⚠️ **FORWARD REFERENCE, ADDED BY SAFETY-48 — THIS TABLE AND THIS SENTENCE ARE
+TRUE OF release/1.0's LAW AND FALSE OF THE ONE THAT REPLACED IT.** Nothing above
+is retracted: re-run on release/1.0 today the same rig prints the same column
+(958 / 1107 / 1133 / 1058 / 987 / 1029 / 1150 / 1143 / 1081 W), flat,
+non-monotone, 800 better than 556. Under SAFETY-48's lead cap the **same script
+on the same plant** prints 777 / 734 / 663 / 563 / 553 / 507 / 435 / 358 / 321 W
+— falling monotonically, so a slower slew is now *better* and the sentence above
+inverts. The mechanism SAFETY-39 identified is exactly why: `slew_w` bounds the
+OUTPUT while the integrator goes on accumulating `gain · error`, so slowing the
+slew used to buy nothing; bound the integrator's lead and it starts to.
+`tools/slew_sim.py --slew` now names which of the two laws it is running under
+before it narrates the column, and
+`DECISIONS/SAFETY-48-bounding-the-integrator-lead.md` §6 carries both tables and
+the independent confirmation from `test_control.py`'s own plant model. ⚠️ **This
+does NOT re-open the choice of 556**: the constraint picks the number, the rig
+does not, and that is unchanged in both laws.
+
 ⚠️ **A single step is not evidence here.** The deadband, the 10 W quantisation
 and the phase of the step against the tick move the result by hundreds of watts,
 non-monotonically. The first cut of this derivation was a single step and ranked

goodwe_controller/DECISIONS/SAFETY-40-the-integrator-bound-is-not-a-bug.md

@@ -0,0 +1,28 @@
+# SAFETY-40: the integrator bound is not a bug
+
+**Decision.** `i_clamped` (the integrator reaching `integrator_max_w`, i.e.
+anti-windup) keeps alarming through the same `ClampWatchdog`: it is counted,
+notified on the same cadence, and escalates on a sustained run
+(SAFETY-41). It gets its own text, a `WARNING` and an amber status row. Only
+`clamped` (a command over `max_w`) and write-path clamps keep the BUG SIGNAL,
+the `ERROR` and the red row.
+
+**Why it still notifies.** On a default install `clamped` is unreachable
+(`control.py`, at the integrator bound), so the integrator bound is the only
+loop-side signal of a runaway such as the 14 768 W one. Silencing it would
+remove that. The card says the same: "the fix is to say the true thing, not to
+say less."
+
+**Why a bug has its own budget.** A genuine over-rating must not wait up to
+`REASSERT_S` behind anti-windup notices. `ClampWatchdog` tracks a separate
+`last_bug_alarm`, and a bug's text is never overwritten by later anti-windup
+text within an episode. Across episodes the WARNING uses its own
+notification id (`goodwe_integrator_bound`), so it cannot replace a BUG SIGNAL
+notice still on screen (review of #130). With only bug engagements, the cadence is the same as
+before (`test_clamp.py` part 9).
+
+**Numbers.** They come from the `Decision` of the clamping tick (`i_bound_w`,
+`requested_w`, `clamped_w`, `target_w`), not from `i_w` or `self.target`.
+
+**Open for the owner.** Whether scattered one-cycle anti-windup episodes should
+notify at all, or only log and count. They notify now, as before.

goodwe_controller/DECISIONS/SAFETY-45-sizing-the-trade.md

@@ -0,0 +1,221 @@
+# SAFETY-45 — the trade is SIZED by the capacity guard, not switched by it
+
+**Status: closed.** `peakguard.charge_headroom_w()` publishes the watts the open
+billed quarter can still afford; `arbitrage.decide()` takes it as a required
+keyword-only argument and sizes the BUY leg to it; `main.py` passes the measured
+guard's own number at its one call site. `peakguard.decide()` is **not changed** —
+byte-identical to `release/1.0` at `478ba93`, `sha256(decide) = 200090d0835a3a55`,
+7252 B on both trees.
+
+⚠️ **THE HOUSE LOAD IN EVERY FIGURE BELOW IS SYNTHETIC.** TEST-23 stage 3's
+`priceloop.py` drives a flat modelled house against a modelled pack
+(`plantsim.Plant`, 800 W/s ramp into a 10 s lag, 15 360 Wh). The PRICES are real,
+the decision code is the shipped code, the billed-quarter accumulator is
+`app/p1.py`'s own — the load is not. Nothing here is a measurement of the live
+site at 192.168.2.158, which this work did not touch.
+
+## 0. The defect, measured
+
+TEST-23 stage 3 found a sustained limit cycle with arbitrage armed and a charge
+decision active. Re-measured here on the same rig against the same checkout,
+metrics recomputed rather than copied — a **charge onset** is a cycle at which
+`arbitrage.decide()` transitions into `ARBITRAGE_CHARGE`, which is the edge the
+rig already logs:
+
+| `peak_cap_w` | house | onsets/h | mean period | grid swing | billed quarters (W) |
+|---|---|---|---|---|---|
+| 1500 | 1200 W | **28** | 131.1 s | **−455.5 … +3200.0 W** | 1490.1 / 1496.5 / **1508.8** |
+| 3500 *(shipped)* | 1800 W | 8 | 509.3 s | +127.5 … +3800.0 W | **3511.3 / 3536.0 / 3559.1** |
+| 3500 *(shipped)* | 3000 W | 32 | 114.8 s | +1202.0 … +5000.0 W | **3518.9 / 3542.2 / 3556.7** |
+| 5000 | 1200 W | 1 | — | +1240.6 … +3200.0 W | 3169.5 / 3200.0 / 3200.0 |
+
+The last row is the **negative control**: `load + max_w = 3200 W` never reaches
+the cap, so there is no cycle to remove. The bite rule is `load + max_w >
+peak_cap_w`, which at the shipped `peak_cap_w: 3500` / `max_w: 2000` is any house
+drawing over 1500 W in the cheapest quarter.
+
+§10.1's ordering did win on the money — the guard kept the quarters within tens
+of watts of the cap — but **every billed quarter in the three biting rows
+finished OVER it**, which is the thing §9.1 bills. §10.2: *"an EMS that
+oscillates is worse than no EMS, both for hardware wear and — per §9.1 — for the
+peak it is trying to avoid."*
+
+## 1. ⚠️ The mechanism is NOT mainly the quarter boundary, and the card says it is
+
+The card, and `.cache/s45.md` before it, describe the loop as *"at each quarter
+boundary the projection resets to 0, the guard disengages, and arbitrage re-arms
+at full power."* **That is not what the 28 onsets are.** Their timestamps, off
+the run above:
+
+    1, 231, 351, 471, 581, 696, 806, 896, 1136, 1256, 1371, 1486, 1596,
+    1711, 1811, 2061, 2176, 2296, 2411, 2521, 2626, 2716, 2971, 3091,
+    3206, 3321, 3431, 3541      (s, quarter boundaries at 900/1800/2700)
+
+**23 of the 27 gaps are 90–120 s, mean 111.5 s, entirely inside one quarter.**
+The four long gaps — 230, 240, 250, 255 s — are precisely the four that SPAN a
+boundary, so the boundary **lengthens** the interval rather than causing an
+onset. Only three onsets land within 15 s of a boundary and one of those is
+`t = 1`, the start of the run.
+
+The real cycle, read off the recorded fields at t = 1000…1180 s:
+
+1. the trade charges at `−2000 W`; the meter sits at 3200 W against a 1500 W
+   ceiling; `wanted = batt_w + excess` is **negative** (−132 → −8 W), so
+   `decide()` files **nothing** and arbitrage is not constrained at all;
+2. `wanted` drifts up as the quarter's own history worsens and the `900 /
+   remaining` gain grows, and crosses zero at t = 1055 with **`floor_w = 5.3 W`**;
+3. that 5 W floor flips `arbitrage.guard_state()` to `True`, which refuses the
+   **whole trade** — so the setpoint goes from −2000 W to +5 W and the
+   grid-following loop, which targets grid = 0 and not grid = ceiling, takes the
+   actuator and discharges to **+1870 W**, exporting 420 W;
+4. the projection collapses, `wanted` goes negative, the guard releases, and
+   arbitrage re-arms at **`max_w`**. 115 s later, again.
+
+So the defect is **a binary interlock keyed on a continuous quantity**, and the
+quarter boundary is one of the ways it is crossed rather than the cause. The
+card's other claim — *"projection 3092 W against a 1509 W ceiling, `engaged=False`,
+for 170 consecutive seconds"* — reproduces, but it is the **first** such window
+(`first_engaged_t_s = 151.0`); the steady-state silent window is ~40–65 s.
+
+None of this changes what the fix has to do. It is recorded because a card that
+says "the boundary is the trigger" invites a fix in the boundary handling, and
+such a fix would have removed four of twenty-eight onsets.
+
+## 2. What was rejected, and why
+
+### 2a. Reverting `decide()`'s `wanted <= 0.0` rung — rejected, and it is a trap
+That rung is 2026-08-20's anti-bang-bang. Its own comment records the cost of not
+having it: 17 engage/release cycles in 900 s and a quarter finishing 49 W over
+the limit it had spent a quarter of an hour holding. It is untouched, pinned on
+the AST in `test_peakguard.py` 13g, and `tools/replay_ac3.py` reproduces the same
+190/190, 110 engaged cycles, 5 blind, 878 Wh on this branch as on `478ba93`.
+
+### 2b. Filing the affordable charge as a NEGATIVE `lo` — rejected
+Arithmetically this is the prettiest answer: `lo = wanted` with no sign gate is
+continuous, is exactly the control law `decide()` already computes, and would
+have put the constraint on the arbiter where it binds every claimant rather than
+only arbitrage. It was rejected on two grounds, in this order:
+
+1. ⚠️ **IT CREATES A NEW `lo > hi` CONTRADICTION CLASS AGAINST THE MAINTENANCE
+   SHAPING.** `main.py`'s cheap-window maintenance charge files
+   `Claim.limit("maintenance", P_MAINT_SHAPE, hi=-floor)` — a NEGATIVE `hi`.
+   `arbiter.py` clause 2 applies every limit at or above the winner's priority
+   and takes the most restrictive, with **no notion of one limit out-ranking
+   another**; a peak `lo = −300 W` against a shaping `hi = −1000 W` is `lo > hi`,
+   which resolves to **0 W — the battery parked, in the one quarter of the month
+   that sets the bill**. That is the exact failure `peakguard.shaping_suspended()`
+   exists to prevent, and the only way to close it would be to key that
+   suppression on "a claim exists" — which, on every site this card is about,
+   means the maintenance charge-only shaping is suspended **permanently**. A
+   silent, large change to a different subsystem is not a price this card should
+   pay.
+2. It changes the meaning of `PeakDecision.engaged` at five call sites outside
+   this module — `arbitrage.guard_state()`, `shaping_suspended()`,
+   `claim()`, `main.py`'s edge-logged action line and `main.py`'s status row —
+   each of which today means "the guard is HOLDING" and would silently start
+   meaning "a claim exists".
+
+`test_peakguard.py` part 5's sweep asserts **no negative floor, ever**, and the
+reason it gives ("a `lo` limit is incapable of capping discharge or export only
+while it is non-negative") is, strictly, not the true reason — a `lo` of any sign
+caps neither. The invariant is still right and is still worth holding; §2b above
+is the argument that actually supports it, and it is recorded here rather than
+left for the next person to re-derive.
+
+### 2c. A backoff, cooldown or hysteresis constant in `arbitrage.py` — rejected
+The card asks whether the second half of the fix belongs in arbitrage: *"a trade
+refused at 14:59 and re-armed at 15:00 has learned nothing from the refusal."*
+It does belong there, but as a **size**, not as a memory. `arbitrage.py`'s
+hysteresis note is explicit that the switching decision is "which hour is it" and
+that **no timer is needed and none is invented**; `peakguard.py`'s design note
+spends a paragraph on why it carries no hysteresis constant. A cooldown would be
+a second control loop compensating for a limit the first one declined to file,
+and its constant would outlive whatever it was tuned against. The trade now
+re-arms at `ceiling − load` instead of at `max_w`, which is what "learning from
+the refusal" means when the refusal is a measurement.
+
+## 3. What was done, and the precedent it follows
+
+`control.maintenance_charge_floor()` has capped MAINTENANCE charging at *"the
+headroom left under the site's cap"* since the loop was written, and its
+docstring says why:
+
+> "A maintenance charge is the only thing this system does that is big enough and
+> long enough to set that peak, so it is capped by the headroom left under the
+> site's cap."
+
+⚠️ **THAT SENTENCE STOPPED BEING TRUE WHEN OPT-04 LANDED.** Price arbitrage is a
+second thing that is big enough and long enough — it commands `max_w` for a whole
+tariff interval, deliberately, against the meter — and it was given no such cap.
+This card gives it the same shape, with one difference that matters:
+`maintenance_charge_floor()` sizes itself from `peak_forecast_entity`, which is
+OPTIONAL and empty on a default install — the exact hole SAFETY-25 had to close
+in `shaping_suspended()`. `charge_headroom_w()` comes off `decide()`, which runs
+wherever P1 does.
+
+**The number is `wanted_w` read in the other direction.** `decide()` already
+computes `wanted = batt_w + excess` as the DISCHARGE that lands the quarter on the
+ceiling; a negative `wanted` is a permitted CHARGE of `−wanted`. No new
+arithmetic, no new constant.
+
+Two properties make it safe to hand a strategy, and both are swept rather than
+argued (`test_peakguard.py` part 13):
+
+* ⚠️ **IT IS INVARIANT IN THE BATTERY.** Raise the charge by dW and the meter
+  rises by dW, so `excess` rises by exactly dW while `batt_w` falls by dW:
+  `wanted` does not move. Measured across `batt_w` from −5000 W to +2000 W on one
+  banked quarter — the headroom is 1350.0 W at every one of the six points while
+  the `excess` those runs see moves through six distinct values. It is a
+  **feed-forward** number, so consuming it adds no feedback path around the plant.
+  The fixed point is `charge = ceiling − load`, with the meter ON the ceiling and
+  `wanted` parked a whole `ceiling − load` clear of the engagement boundary.
+* **HOLDING IMPLIES ZERO OR UNKNOWN.** Across 1080 swept combinations, not one
+  ENGAGED decision answers a positive headroom, so the function can never hand a
+  caller permission the guard's own `lo` is at that instant refusing.
+
+## 4. After, on the same rig, same command, same checkout
+
+| `peak_cap_w` | house | onsets/h | grid swing | energy bought | billed quarters (W) |
+|---|---|---|---|---|---|
+| 1500 | 1200 W | 28 → **1** | 3655.5 → **282.0 W** | 180.0 → **285.2 Wh** | **1500.0 / 1500.0 / 1500.0** |
+| 3500 | 1800 W | 8 → **1** | 3672.5 → 1687.6 W | 1652.9 → 1616.1 Wh | **3500.0 / 3500.0 / 3500.0** |
+| 3500 | 3000 W | 32 → **1** | 3798.0 → **474.7 W** | 482.9 → 475.3 Wh | **3500.0 / 3500.0 / 3500.0** |
+| 5000 | 1200 W | 1 → 1 | **identical** | **identical** | **identical** |
+
+* **One onset** means the trade starts once and runs for the whole window. The
+  battery is trading 100 % of the hour where it used to trade 43 %, 92 % and 54 %.
+* **Every billed quarter lands exactly on the cap and none over it**, where every
+  quarter in the three biting rows used to finish over.
+* **The money.** At 1500/1200 the site buys **58 % MORE** energy, because a
+  continuous 300 W trade beats a 2000 W trade that is cancelled for 57 % of the
+  hour. At the two shipped-default rows it buys **2.2 % and 1.6 % less** — and in
+  exchange the worst quarter drops from 59 W over the cap to 0 W over it. The
+  capacity tariff bills the month's single worst quarter with no averaging and no
+  forgiveness (specs.md:583), so that is not a trade-off, it is the ordering
+  §10.1 asks for.
+* The remaining 1687.6 W at 3500/1800 is the opening **ramp**, not a cycle: the
+  pack goes from 0 to 1700 W of charge in about ten seconds and the meter with
+  it. One onset, no export, no reversal.
+* The last row is bit-identical before and after. **This card costs nothing on
+  the installs it is not about.**
+
+## 5. What this does NOT fix, with sizes
+
+* **TEST-23 finding 1 — the export overshoot at the END of a trade** (356–938 W,
+  ≈0.37 × `max_w`) is untouched and is a different card. It happens when the
+  cheap interval ends and the grid-following loop takes back an actuator that was
+  holding a charge; nothing here changes the handover.
+* **A house whose load ALONE exceeds the cap** (`load > peak_cap_w`) still puts
+  `wanted > 0`, still engages the guard, and still refuses the trade outright
+  through the interlock — correctly, since you cannot buy in a quarter you are
+  already over on. The loop then drives to grid = 0 rather than to grid =
+  ceiling, which is more discharge than the guard asked for. Not swept here: all
+  four (cap, load) pairs on the record have `load < cap`.
+* **`arbitrage.claim()` still files the SIZED number, but the ARBITER can clamp
+  it further** and the strategy is not told. The reason line names the guard's
+  headroom, not the arbiter's `bound_by`. Pre-existing; not widened.
+* **The container leg was not re-run.** `hadrive.py` needs `test23s3-addon`
+  started, and that container is deliberately stopped because it is a second
+  writer on the setpoint entity under measurement. The in-process rig's twelve
+  transcribed lines are pinned by `test_arbitrage.py` 3b's AST check on
+  `main.py`'s call site, which is the line this card adds to them.

goodwe_controller/DECISIONS/SAFETY-47-what-a-shadow-run-can-show.md

@@ -0,0 +1,319 @@
+# SAFETY-47 — what a shadow run can show, and what it cannot
+
+**Status:** decided and implemented on branch `SAFETY-47`.
+**Card:** SAFETY-47 — *"shadow mode's claims, and the number on the status
+row"*.
+**Nothing here reached the inverter.** No deployment, no `ha addons update`, no
+contact with 192.168.2.158 or 192.168.2.221. Everything below was measured in
+the CI image and on TEST-23 stage 3's closed-loop rig.
+
+⚠️ **This is not a write-path defect and nothing in the write path was
+touched.** SAFETY-10's substitution, re-seed, authorisation gate and clamp are
+unchanged. What was wrong is what three merged documents **say** a shadow run
+can show you, and a number on the status row that can be **6.61×** what a live
+controller would command.
+
+---
+
+## 0. The four things a reader should take away
+
+1. **Shadow mode cannot surface a closed-loop defect. Not partially — not at
+   all**, and by the same construction that makes it safe. §1.
+2. **The "strategies are unaffected" exemption was true until SAFETY-45 merged,
+   one commit before SAFETY-10.** Sizing the buy leg to the billed-quarter
+   headroom made the strategy closed-loop. §2.
+3. **The recorded watts are the right answer to a question nobody asked, and
+   they are CAVEATED rather than re-computed.** Re-computing would mean the
+   recorded decision was no longer the decision the shipped path reached, which
+   is the one thing shadow mode has to be able to say. §3 records what was
+   rejected.
+4. **SAFETY-10 §6's committed evidence could never have failed, for two
+   independent reasons, and closing either one alone closes nothing.** §4.
+
+---
+
+## 1. Why the answer is "not at all", and not "not very well"
+
+Shadow mode holds every actuator at `shadow.WIRE_W` and re-seeds the carried
+command to it at the end of each cycle. So every **measured** input — the
+meter, the billed-quarter accumulator behind it, the battery power, the state
+of charge — describes a plant that **did not respond**.
+
+A closed-loop defect is, by definition, one whose stimulus **is** the plant's
+response to the controller. No response, no stimulus, nothing to see. This is
+not an implementation gap:
+
+* feeding the guards a **simulated** plant instead is exactly what SAFETY-10 §4
+  refuses for the sign watchdogs, and the reason generalises — a controller
+  reacting to a plant that does not exist drifts further from reality every
+  tick, and three cycles in its numbers describe nothing;
+* and SAFETY-10 §5 already conceded the same fact for the grid-following loop
+  ("one slew step, not a trajectory"). That was never a property of the loop.
+  **It is the general case**, and the loop leg was simply where it had already
+  been noticed.
+
+**So the closed-loop answer comes from a closed-loop rig (TEST-23 stage 3) or
+from a live run. There is no third place, and saying that plainly is worth more
+than the three sentences it replaces.**
+
+### Measured, on the rig, at a cap that binds
+
+`peak_cap_w` 1500 / house 1200 / `max_w` 2000, one hour at a 5 s cycle. Of the
+three defects SAFETY-10 was written for:
+
+| | visible? | measured |
+|---|---|---|
+| SAFETY-45's limit cycle | **no** | 28 charge onsets live, **1** in shadow. Grid −455.5 … +3200.0 W live, **flat at the 1200 W house** in shadow. Guard engaged 410/720 cycles live, **0/720** in shadow. (Taken with SAFETY-45 reverted — that is the defect being looked for.) |
+| SAFETY-46's SoC churn | **no** | the SoC moves **0.000000000 pp** in a shadow run. The SoC is the pack's integral of what the pack was commanded, and it was commanded 0 W. No SoC limit can be *reached* in a shadow run at all |
+| TARIFF-14's wrong quarter-hour | **yes**, and it is the only one | the price lookup's inputs are the clock and the price series, neither a function of the battery. Which hour, at what price, clearing what spread: **identical live and shadow on 720 of 720 charging cycles, at a binding cap** |
+
+### What a shadow run genuinely is for
+
+*Which* strategy wins, on *which* hour, at *which* price, for *which* reason,
+against which limits — the wrong-quarter-hour class, a trade armed on a day it
+should not be, a refusal whose sentence names the wrong subsystem, a clamp that
+would have engaged, a standing failsafe latch. That is a real and useful set,
+and it is the set the documents now claim.
+
+---
+
+## 2. The exemption, and exactly how much of it survives
+
+All three documents carried a version of:
+
+> The **strategies** are unaffected — price arbitrage, the capacity guard and
+> maintenance all ask for a fixed power **from inputs that do not depend on
+> what the battery did**.
+
+**True before SAFETY-45, false after it.** SAFETY-45 makes the buy leg
+`min(asked, headroom)`, and
+
+```
+headroom = (900 / remaining) x (ceiling - projected)
+```
+
+where `projected` reads the **open quarter's accumulator** — the meter — which
+is a function of what the battery did earlier in that same quarter. SAFETY-45
+merged one commit before SAFETY-10, so the exemption was stale on the day it
+was written.
+
+**What survives, and it is now graded rather than asserted:**
+
+> **Which** hour a strategy picks, and **why**, are unaffected — the clock and
+> the price series are not functions of the battery.
+> **How hard** it trades is not.
+
+⚠️ **The peak guard is not in the surviving half either.** Every term of
+`wanted = batt_w + excess` is measured, so in a shadow run the guard engages
+only if the *house alone* would put the quarter over the ceiling. Its
+**ceiling** and its **reasons** are worth reading from a shadow run; its
+**engagements** are not evidence of anything.
+
+---
+
+## 3. The number on the status row — decided, and what was rejected
+
+At `peak_cap_w` 1500 under a 1200 W house the status row read **"WOULD HAVE
+COMMANDED −2 000 W"**. A live controller commands **−302.4 W**. Measured on the
+shipped build:
+
+| cap / house | live commanded | shadow recorded | over by |
+|---|---|---|---|
+| 1500 / 1200 | −302.4 W | **−2000.0 W** | **6.61×** |
+| 3500 / 3000 | −502.6 W | −2000.0 W | 3.98× |
+| 3500 / 2000 *(shipped cap)* | −1502.6 W | −2000.0 W | 1.33× |
+| 3500 / 1800 | −1702.6 W | −2000.0 W | 1.17× |
+| 15000 / 350 | −2000.0 W | −2000.0 W | 1.00× |
+
+⚠️ **The arithmetic is not wrong.** `900/remaining` is correct for a meter that
+is genuinely under the ceiling, and in a shadow run the meter genuinely *is*
+under it, because the battery is not charging. **The recorded number is the
+right answer to a question nobody asked** — and the last row of that table is
+the fixture SAFETY-10's own evidence was taken on, which is why nothing
+reported it.
+
+### What shipped
+
+1. **Unconditionally**, the row and the log line stop forecasting: the watts
+   are introduced as what would have been commanded **ON THIS CYCLE**. No
+   number a shadow run records is a prediction of a live run, so no state
+   should read like one.
+2. **Conditionally**, whenever a **measured** billed quarter sized the number
+   being recorded, both surfaces carry `shadow.SIZED_FROM_METER`:
+
+   > ⚠️ AND ITS SIZE CAME FROM THE BILLED-QUARTER METER, WHICH HAS ONLY THE
+   > HOUSE IN IT WHILE THE BATTERY IS HELD AT 0 W. A live run sizes the same
+   > trade against a meter the battery is moving, so this is an UPPER BOUND and
+   > not a prediction; how far under it a live run lands is a closed-loop
+   > question and a shadow run cannot answer it.
+
+⚠️ **"Upper bound", and not "smaller", and the difference was measured.**
+Charging only *adds* offtake, so a live `projected` is never below a shadow one
+and the headroom never above it — with **equality at the start of every
+quarter**, where `900/remaining` is 1.0 and neither plant has moved. Measured
+pairwise over 3600 charging cycles in five configurations: **0 cycles below,
+730 exactly equal.** A sentence reading "smaller" would have been false on
+every one of those 730, and the first draft of this card said "smaller".
+
+⚠️ **And it names no factor.** How far under the bound a live run lands is a
+property of the site. A number invented for the row would be a second helping
+of the defect the sentence exists to disclose.
+
+⚠️ **The predicate is NOT keyed on whether the trade was capped, and that is
+the trap this card nearly walked into.** `arbitrage`'s own sentence says *"SIZED
+BY THE CAPACITY-TARIFF GUARD"* only when the headroom came out **below** the
+ask — which in a shadow run is the **start** of the quarter, where the two runs
+still agree to the float. By the end, `900/remaining` has multiplied the
+headroom **past** the ask, the trade is **not** capped, the sentence is silent,
+and the recorded number is at its **most** wrong. A caveat keyed on it would be
+quietest exactly where it is needed loudest. `arbitrage.sized_from_meter()` is
+keyed on the headroom having been **measured**, so it fires on both.
+`test_arbitrage.py` part 3d-8 drives the inversion.
+
+### Rejected, and why
+
+* **Re-compute the number so it does not amplify** — e.g. record
+  `ceiling − projected` (gain 1.0) instead of the sized figure. It matches the
+  live answer almost exactly at this cap, and it is the **worst** of the
+  options. It would be a **shadow-only sizing**: the recorded decision would no
+  longer be the decision the shipped path reached, while the arbiter, the
+  clamp, SAFETY-28's gate, the action log and MQTT all ran on the real one. A
+  second copy of the sizing arithmetic living in the display layer is
+  MUTATION.md's transcribed-predicate defect on an operator-facing surface, and
+  it generalises to no other strategy. SAFETY-10's whole safety argument is
+  that shadow mode is a **substitution at the wire**, not a second controller;
+  this would have made it a second controller everywhere except the wire.
+* **Record nothing where the sizing depends on measured state.** Tempting —
+  "no number beats a number 6.61× out". Rejected on three counts: it blanks the
+  row exactly when arbitrage is trading, which is when a commissioning engineer
+  most wants it; the action log's edge key is the rounded watts, so blanking
+  them either floods or silences the log; and a surface that flickers between a
+  number and a dash is harder to read than a number with a standing caveat.
+  The narrow version of this — dropping the watts only — was the closest
+  runner-up.
+* **Record the unsized ask alongside the sized one.** It adds a number without
+  adding a warning. The unsized ask is `max_w`, a constant the operator
+  configured; on the shipped 3500/2000 row both figures are 2000 W, so the pair
+  is exactly as misleading as the single figure was.
+* **A caveat on every cycle in every state.** Rejected as the *whole* answer,
+  accepted as half of it: the unconditional part is a two-word narrowing of the
+  verb ("on this cycle"), not a warning, and the warning proper is conditional
+  so that it still means something when it appears.
+
+---
+
+## 4. SAFETY-10 §6's evidence, and why it could not fail
+
+§6 tabulated `arb_power_w` −2000 W *"identical"*, `arb_reason` *"identical,
+verbatim"*, arbiter winner *"identical"*. Two independent reasons it could
+never have gone red:
+
+1. **the fixture is `peak_cap_w: 15000` against a 350 W house**, so the guard
+   never engages and SAFETY-45's sizing is in the run and inert. ⚠️ **The
+   harness's own comment says so** — *"at this scenario's `peak_cap_w: 15000`
+   it is not binding anyway"* — which is MUTATION.md habit 4 written down
+   beside the check it disables;
+2. **every identity row reads the FIRST charging sample.** At `elapsed = 0` the
+   projection *is* the held level, so the two runs agree to the float there
+   **even at a cap that does bind**.
+
+⚠️ **AND THAT SECOND REASON IS THE ONE A REVIEWER CANNOT SEE FROM A DIFF.**
+Widening the fixture alone — the obvious fix — leaves the `[0]` comparison
+passing. Measured, not reasoned: at 1500/1200 the first charging cycle is
+−300.0000 W in **both** runs while 716 of the 720 cycles differ. Part 3d-2
+grades that agreement **as an expectation**, so nobody rebuilds a check on
+`[0]` believing it covers something.
+
+This is habit 4's **twelfth** instance in this repository, its **second**
+inside a committed evidence artifact, and — like the seventh and the eleventh —
+it was in a **measuring instrument** rather than in a check.
+
+§6 is re-taken at `peak_cap_w` 1500 / house 1200 / `max_w` 2000, across the
+whole run. Harness `/home/homelab/s47-mut/shadowloop47.py`.
+
+---
+
+## 5. The grader, so this class cannot recur
+
+`test_arbitrage.py` part **3d** — placed beside part 3c, which is SAFETY-45's
+own closed-loop regression, and built on the **same** `s45_loop()` harness so
+the two runs share every line of shipped code and differ in **one argument**:
+
+```
+s45_loop(sized=True)                  the live hour
+s45_loop(sized=True,  shadow=True)    the same hour, battery held at WIRE_W
+s45_loop(sized=False, shadow=True)    SAFETY-45's own defect, watched from
+                                      inside shadow mode
+```
+
+Three lines of `s45_loop()` stand in for `Controller._write_unit()`'s
+substitution and `_shadow_settle()`'s record and re-seed. They are marked as a
+**transcription**; `test_clamp.py` part 8 is the check on the shipped
+placement, and it drives the real `Controller`. Everything that produces a
+number — the averager, the projection, the guard, the headroom, the strategy,
+the arbiter, the row and the log sentence — is the shipped one.
+
+What 3d grades, in order: that the cap **binds** (the precondition the old
+evidence lacked); that the first charging cycle agrees **anyway**; that the
+whole run diverges, and by how much; that the record is an **upper bound**, and
+the two-point arithmetic that makes it one; what survives of the exemption;
+that SAFETY-45's limit cycle and the guard's engagements are **not** visible;
+the four rungs of `sized_from_meter()`, each reached with the other three clear
+(TEST-16); both operator surfaces; the `capped`-keying trap; and main.py's
+three call sites, pinned on the AST.
+
+⚠️ **The section carries its own precondition into every check.** A mutation
+that stops either run trading left the lists empty, the first `min()` raised,
+the file died before part 4 and the run reported **zero reds — which reads
+exactly like a survivor**. That is FCST-06's shape and it was **driven**, not
+imagined. `s47check()` now fails every check in the section when the stimulus
+was not produced, and the one division in it answers `nan` rather than raising.
+
+---
+
+## 6. The mutation battery — 14 mutations, no survivors
+
+Harness `/home/homelab/s47-mut/run.py`, backups inside it. Each run restores
+from backup, purges `__pycache__` **on the host**, and grades through the CI
+image with the tree bind-mounted `:ro`, so the interpreter cannot write a cache
+into the tree under test (TEST-15). Fingerprints are printed before the first
+run and re-checked after the last restore.
+
+| # | mutation | file | Δ | reds |
+|---|---|---|---|---|
+| M1 | the row drops the caveat branch | `shadow.py` | −63 B | 2 |
+| M2 | **the trap**: `sized_from_meter()` keyed on the trade being CAPPED — silent where the record is multiples out | `arbitrage.py` | +33 B | 5 |
+| M3 | the CHARGE rung dropped — a sell carries a caveat §9.1 makes false | `arbitrage.py` | −30 B | 1 |
+| M4 | the measured-headroom rung dropped | `arbitrage.py` | −18 B | 1 |
+| M5 | the arbiter-winner rung dropped — a caveat on somebody else's number | `arbitrage.py` | −33 B | 1 |
+| M6 | `main.py` renders the row with `sized_from_meter=False` | `main.py` | −23 B | 1 |
+| M7 | `main.py` drops `winner=` — the rung exists and is never reached | `main.py` | −1 B | 1 |
+| M8 | `main.py` sizes the trade from a literal — SAFETY-45 out of the shipped path, which the hoist put at risk | `main.py` | −41 B | 2 |
+| M9 | the headroom assignment moves out of `cycle()` | `main.py` | −39 B | 1 |
+| M10 | `sized_from_meter` gains a `False` default (TEST-14) | `shadow.py` | +8 B | 1 |
+| M11 | `ON THIS CYCLE` deleted — the row forecasts again | `shadow.py` | −14 B | 1 |
+| M12 | `log_line()` drops the caveat — the page discloses, the record does not | `shadow.py` | −63 B | 2 |
+| M13 ⚠️ | `main.py` re-assembles the log sentence at the call site | `main.py` | **+0 B** | 1 |
+| M14 ⚠️ | `wanted = batt_w − excess` — the headroom stops being monotone in the battery and the row's UPPER BOUND sentence becomes false | `peakguard.py` | **+0 B** | 38 |
+
+**Survivors: none.**
+
+⚠️ **M13 and M14 are `+0 B`, which MUTATION.md names as the risky delta.** Both
+were confirmed on disk by `sha256` before the run started — the harness prints
+the fingerprint of every graded file and the hash moved for each — and every
+run is purged, so neither is at risk of the stale-`.pyc` failure.
+
+⚠️ **Two findings from driving it, both reported rather than tidied away.**
+
+* **M14's first form was aimed at the wrong direction and correctly survived.**
+  `min` → `max` in the buy leg's sizing makes the shadow record *larger*, which
+  is still an upper bound, so 3d-3b was right not to fail. The mutation that
+  actually inverts the bound is the sign of the excess term in `wanted`. A
+  survivor that is right is worth more than a red aimed at the wrong claim.
+* **M12 was a survivor before the fix it forced.** Deleting the caveat from the
+  action-log line left **all 29 files green**: the only check that could see
+  that line drives a fixture with `meter_source: off`, where no arbitrage
+  decision — and therefore no caveat — is reachable. The sentence was an
+  f-string inside `Controller._shadow_settle()`, i.e. a surface no check could
+  grade. It is `shadow.log_line()` now, for the reason `words()` is a function,
+  and M13 is the mutation that puts it back at the call site.

goodwe_controller/DECISIONS/SAFETY-48-bounding-the-integrator-lead.md

@@ -0,0 +1,551 @@
+# SAFETY-48 — the slew step ceiling reaches the integrator, and what it bounds is the LEAD
+
+**Status:** decided and implemented on branch `SAFETY-48`, on top of `TEL-10`.
+**Card:** SAFETY-48 — *"the integrator goes on winding while the command is
+slew-limited"*.
+**Nothing here reached the inverter.** The live install still runs `slew_w: 400`
+applied by hand on 2026-09-05 12:00 and `release/1.0`'s control law. This branch
+does not deploy and does not bump the version.
+
+---
+
+## 0. The four things a reader should take away
+
+1. **It is a missing case, not a wrong constant, and the arithmetic says so.**
+   The integrator moves `gain * error` a cycle and the command moves at most
+   `slew_w`, so the integrator outruns the command whenever
+   `|error| > slew_w / gain` — 667 W at the live shape. SAFETY-39's retune made
+   `slew_w` **smaller**, which makes that threshold **lower**. §1.
+2. ⚠️ **THE FORM THE CARD ASKED FOR RAISES THE BILLED QUANTITY, AND THAT IS WHY
+   IT IS NOT WHAT SHIPPED.** Reusing the asymmetric freeze on a carried slew
+   flag cuts export 13 % and moves the worst quarter-hour average **offtake**
+   from 3739 W to **3935 W**, with the mean quarter +2.7 W — and on the billed
+   quarter it is worse at **every plant lag where release/1.0 produces a peak
+   at all** (a tie at lag 0, worse at 2.5 / 5.0 / 7.5 / 10.0 s) and at **every
+   top-N cut of the quarters**, which makes this the least lag-sensitive result
+   in the card. The harm is a tail redistribution inside quarters that already
+   net to offtake, not a weaker answer to import in aggregate. §3, §3a.
+3. **What ships bounds the LEAD at one slew step, only where the slew is what
+   stopped the command, and only in the leading direction.** The robust result
+   is the **export reduction — 39.6 → 34.1 kWh, and it falls at every plant and
+   tuning tried** — with wasted throughput 4.67 → 3.19 kWh, sign reversals
+   2992 → 2770 and median recovery 232 → 199 s. ⚠️ **The billed quarter is not
+   something this card can claim.** It reads 3739 → **3434 W** at the fitted
+   plant lag of 7.5 s; at every lag ≤ 5.0 s — including the one that best
+   reproduces the recorded export — release/1.0 is *already* at 3434 W and this
+   card moves it by exactly zero. The lag is not identified by the data. §4,
+   §3a.
+4. **Two committed numbers moved and neither is a silent edit.** SAFETY-13's
+   released command settles lower, because there is less wound integrator to
+   settle onto; and SAFETY-39's *"the slew does not own the over-absorption"* is
+   now **false — inverted, on its own independent plant model.** §5, §6.
+
+---
+
+## 1. The defect, in the terms the code uses
+
+`compute()` freezes the integrator with an asymmetric rule, and the comment
+beside it states the requirement outright:
+
+> the requirement is that the INTEGRATOR stop accumulating, not only the command
+
+But `frozen` is computed from **one** signal:
+
+```python
+saturated_now = abs(prev_w - actual_w) > tuning.saturation_w   # not tracking
+```
+
+Slew-limiting never enters it. When the command hits the step ceiling the
+integrator keeps winding at `gain * error` until it reaches `integrator_max_w`,
+and the unwind afterwards is `integrator_max_w / slew_w` cycles — 12.5 at the
+live shape, about a minute at the meter's measured tick.
+
+⚠️ **AND THE RETUNE MADE IT MORE FREQUENT, NOT LESS.** `|error| > slew_w / gain`
+is 1667 W at `slew_w: 1000` and **667 W** at `slew_w: 400`. The measured median
+grid error at the onset of a recorded episode is 1114 W — above the second
+threshold and below the first. This is why SAFETY-39 did not fix it, and the
+mechanism is the same one §6 shows inverting.
+
+## 2. How it was measured, and what the measurement cannot say
+
+`tools/replay_recorded_loop.py`, over **16.00 days / 256 252 meter instants** of
+the live install's own recorder, exported read-only.
+
+**Real:** the disturbance (`D = grid + batt` at every recorded meter instant —
+the house with this loop's own battery taken back out, which is exogenous and
+therefore valid to drive a counterfactual with); the tick (the meter's own
+recorded instants, median **5.01 s**); and the control law, imported out of the
+checkout. The "before" law is the **same file** with the SAFETY-48 block removed
+by a named substitution and exec'd into a fresh namespace — never a
+transcription — and a missing or duplicated anchor is a **refusal** with
+`NOTHING HAS BEEN MEASURED` on it, because an instrument that quietly compared
+the shipped law with itself would report the card as changing nothing.
+
+**Modelled:** the inverter (pure delay 7.5 s + first-order lag 2.0 s +
+`batt = 0.973 × cmd − 22.4 W`, fitted on this same recording above the SoC
+floor, residual **375 W RMS**); the pack (SoC integrated, discharge refused at
+or below the floor); and **everything else the arbiter does** — the recorded
+setpoint is the arbiter's output after the peak guard, the SoC clamps,
+maintenance and arbitrage, while the replay runs `compute()` alone.
+
+⚠️ **THE ABSOLUTE FIGURES ARE PESSIMISTIC BY ABOUT A THIRD AND THE TOOL PRINTS
+IT ON EVERY RUN.** Replaying the before-law reproduces 39.6 kWh of export where
+the install actually exported **29.4 kWh** over the same window. The delta is
+what this instrument is for: both laws run on the same ticks, the same
+disturbance, the same plant and the same seed.
+
+⚠️ **THE SoC FILTER ON THE PLANT FIT IS THE WHOLE FIT, AND IT IS A FINDING IN
+ITS OWN RIGHT.** This install spends **36 % of its ticks at or below a 10 % SoC
+with the command standing near 2 kW and the battery delivering nothing.** Fitted
+over all ticks the recording says `batt = 0.50 × cmd − 396 W, r = 0.70` — a
+plant that follows half the command, which no inverter does. Above the floor the
+same data says `batt = 1.00 × cmd − 28 W, r = 0.977`. The floor is the PACK and
+is modelled separately.
+
+## 3. The form the card asked for, and the number that refused it
+
+The card asked for the asymmetric rule already in service for saturation, on a
+flag carried across cycles the way `sat_count` is. It was built — from
+release/1.0's own source, one substitution per change — and measured on the same
+16 days through the same pipeline:
+
+| | release/1.0 | **form A** — carried slew flag + the asymmetric freeze | **SAFETY-48** — the lead cap |
+|---|---:|---:|---:|
+| export kWh | 39.61 | 34.43 | **34.07** |
+| import kWh | 116.07 | 110.62 | 111.20 |
+| battery sign reversals | 2992 | **2656** | 2770 |
+| wasted throughput kWh | 4.67 | **2.99** | 3.19 |
+| **worst 15-min offtake W** | 3739 | ⚠️ **3935** | **3434** |
+| mean quarter-hour offtake delta | — | ⚠️ **+2.73 W** | **−2.39 W** |
+| worst quarter-hour delta | — | +992 W | +532 W |
+| recovery median s | 232 | **184** | 199 |
+| recovery p99 s | 849 | **781** | 850 |
+| recovery max s | 901 | 890 | 898 |
+| unrecovered (> 900 s) | 53 | **26** | 31 |
+| \|i_w − prev_w\| p99 W | 3361 | 1534 | **800** |
+| \|i_w − prev_w\| max W | 9200 | 6912 | **800** |
+
+**Form A wins on four rows and loses on the one that is billed.** The capacity
+tariff (*capaciteitstarief*) bills the month's worst quarter-hour average
+offtake, and form A raises it by **196 W** — and raises the MEAN quarter by
+2.7 W, so this is systematic and not one unlucky quarter. It does so in **five
+of the six** plant and tuning variants in `--sensitivity`; the sixth is a tie.
+
+The per-cycle mechanism is that a frozen integrator stops at
+`prev + gain·error(first cycle)`, which is `(1 − gain)` short of what the site
+needs — 40 % short at `gain: 0.6`.
+
+⚠️ **AND THE SENTENCE THAT USED TO FOLLOW THAT ONE WAS TOO BIG FOR THE DATA.**
+It read *"for an IMPORT it is offtake, so a large import is answered too weakly
+for as long as the ramp lasts"*. The aggregate does not show a weaker answer to
+import: form A cuts total import by **5.45 kWh** and export by **5.18 kWh**
+against release/1.0, and paired tick by tick it delivers **8.56 kWh LESS**
+offtake energy on the ticks release/1.0 spent importing (lower on 38 229 such
+ticks, higher on 19 669). What form A moves is the **TAIL, within quarters that
+already net to offtake** — the worst quarter goes 3739 → 3935 W, the top five
+3260 → 3300 W, the top fifty 1880.0 → 1882.7 W. The capacity tariff bills the
+worst quarter and nothing else, so a redistribution that leaves the mean alone
+and lifts the maximum is exactly the trade that is refused here. The conclusion
+is unchanged; the causal sentence is now the one the data supports.
+
+⚠️ **THE CARD SAID "do not invent a second rule", AND THE MEASUREMENT SAYS TO.**
+That instruction is recorded here rather than quietly dropped. What ships is a
+different rule; the paragraph above is why.
+
+## 3a. ⚠️ The plant lag is NOT identified by this recording, and the billed quarter is the claim that depends on it
+
+`fit_plant()` picks `lag 7.5 s` because it minimises **battery-power RMS**. That
+objective barely distinguishes the candidates — 375.3 W at 7.5 s against 376.4 W
+at 2.5 s, **0.3 %** — while the tool's *own* printed fidelity measure, replayed
+export against the **29.43 kWh this install actually exported**, prefers 2.5 s by
+the whole of the 35 % gap the header warns about. Two measures on the same data
+disagree, and nothing here breaks the tie.
+
+So the sweep has to be read as a sensitivity, not as a confirmation:
+
+| plant lag | fit RMS W | replayed export kWh (release/1.0) | **worst 15-min offtake W:** release/1.0 | form A | SAFETY-48 | mean quarter ΔW |
+|---:|---:|---:|---:|---:|---:|---:|
+| 0.0 | 392.3 | 23.5 | **3434** | 3434 | **3434** | +0.53 |
+| 2.5 | **376.4** | **28.9** ← nearest 29.43 | **3434** | ⚠️ 3732 | **3434** | −0.59 |
+| 5.0 | 378.0 | 32.1 | **3434** | ⚠️ 3711 | **3434** | −1.02 |
+| 7.5 | **375.3** ← chosen | 39.6 | 3739 | ⚠️ 3935 | **3434** | −2.39 |
+| 10.0 | 384.2 | 75.4 | 3954 | ⚠️ 4326 | **3434** | −4.65 |
+
+(The RMS column is `fit_plant()`'s own inner sweep pinned to one lag — best `tau`
+and a re-fitted gain/offset at that lag. The export and quarter columns follow
+`--sensitivity`'s convention instead: only the lag is substituted into the
+global fit, everything else held. That is why the lag 5.0 and 10.0 export
+figures are the ones already printed in §7b.)
+
+⚠️ **AT EVERY LAG ≤ 5.0 s THE IMPROVEMENT IS NOT AN IMPROVEMENT — IT IS AN
+ABSENCE.** release/1.0's worst quarter is *already* 3434 W there and SAFETY-48
+changes it by **exactly zero**. §7b's paragraph used to read the `3434 → 3434`
+rows as "the direction does not move"; that is the wrong reading. The direction
+has nothing to move: at those plants release/1.0 never produces a quarter worse
+than 3434 W in the first place, and the 3739 → 3434 W headline exists only at
+the single longest lag `fit_plant()` happens to select. **The peak claim is a
+property of the plant model, not of the card.** What the card can claim on the
+billed quantity is that it does not make it worse, at any lag.
+
+⚠️ **AND THE ONE RESULT HERE THAT IS NOT LAG-SENSITIVE IS THE FORM-A
+REJECTION.** Form A's worst quarter is the worst of the three at **every lag
+where release/1.0 produces a peak at all** — 3732, 3711, 3935, 4326 against
+release/1.0's 3434, 3434, 3739, 3954 at lags 2.5 / 5.0 / 7.5 / 10.0, and a tie
+at lag 0.0 where both sit at 3434. It is worse at every top-N cut of the
+quarters at the fitted plant (top-1 3934.6 against 3738.7, top-5 3299.7 against
+3260.5, top-10 2890.6 against 2871.0, top-50 1882.7 against 1880.0, top-100
+1481.7 against 1479.0), and it raises the mean quarter. §3 understated this: the rejection does not rest on one unlucky
+quarter at one plant, which is exactly the objection a lag-sensitive result
+invites.
+
+⚠️ **WHAT WOULD SETTLE IT IS NOT IN THIS RECORDING.** Both objectives above are
+computed from the same four recorded entities, and they disagree; nothing else
+in the capture breaks the tie, and this card did not go looking for a third
+objective after seeing which lag each of the first two preferred. A driven step
+response — the command timestamped where it is written rather than where Home
+Assistant recorded it — is what identifies a lag. That is a rig measurement and
+it is not this card. Until it exists, the export reduction is what this card
+delivers and the peak figure is a plant-model artefact.
+
+## 4. What ships
+
+```python
+    slew = slew_limit_w(tuning)
+    slewed = max(prev_w - slew, min(prev_w + slew, target))
+    if slewed != target:
+        reason = "slew-limited"
+        _lead_cap = SLEW_LEAD_STEPS * slew
+        if target > slewed:
+            i_w = min(i_w, slewed + _lead_cap)
+        elif target < slewed:
+            i_w = max(i_w, slewed - _lead_cap)
+    target = slewed
+```
+
+Four properties, and each of them is a decision:
+
+* **It is inside the branch**, and ⚠️ **that placement was a SURVIVOR of all
+  thirty files until a check was written for it.** Applying it to every cycle
+  instead — `i_w = max(target - cap, min(target + cap, i_w))` after
+  `target = slewed`, −92 B — is **bit-identical on the shipped configuration**:
+  0 of 256 246 ticks differ over the 16-day recording. The two separate **only**
+  where `integrator_max_w` is set ABOVE `max_w` — the configuration `control.py`
+  says is the only way its `clamped` reason is reachable. There the integrator
+  is *deliberately* allowed above the rail, and an unconditional cap would drag
+  it back to the command every cycle and make the option inert.
+  `test_telemetry.py` part 4 drives that configuration, and the unconditional
+  form is red on it.
+
+  ⚠️ **THE COUNT OF SEPARABLE STATES IS DECORATION AND THREE SWEEPS DISAGREE
+  ABOUT IT.** This card's grid gave **2050 of 257 400**; an independent review
+  measured **1220 of 246 064**; a third, smaller grid (four tunings × 7 `prev_w`
+  × 9 `grid_w` × 5 `actual_w` × 8 `i_w` including `None` × 4 `sat_count`) gives
+  **776 of 40 320** — and that third one is spelled out here precisely because
+  the first two are not, which is the whole reason they cannot be reconciled.
+  No count here should be read as exact without the grid beside it. All three
+  agree on the load-bearing part, which is **where**: every separable state sits
+  in the `integrator_max_w > max_w` tuning and nowhere else.
+
+  ⚠️ **AND AN EARLIER DRAFT OF THIS BULLET GAVE THE WRONG REASON AND THE WRONG
+  NUMBER.** It said the two forms differ on 118 ticks because an unconditional
+  cap would pull the integrator toward a command the SATURATION freeze is
+  pinning. That 118 was measured against a *different* pair — a band applied
+  after quantisation, at the very end of `compute()` — and the saturation story
+  does not apply to the placement actually being compared, which sits before
+  the freeze. The figures above are the ones that were measured on the pair the
+  sentence names.
+
+  ⚠️ **AND THE SATURATION STORY IS NOT MERELY INAPPLICABLE — IT IS BACKWARDS.
+  THE NARROW CAP THAT SHIPPED *DOES* MOVE A SATURATION-FROZEN INTEGRATOR.** It
+  sits before the freeze block and is not gated on `frozen`. Measured on the
+  same 16 days at the live shape: of **79 160** frozen ticks the cap changed
+  `i_w` on **1095**, and on **679** of those it moved it further out on the side
+  it was already on — putting back magnitude the freeze had just let fall, which
+  is the one direction the freeze's rule ("may fall, never rise") exists to
+  forbid. Worst case **2424 W**, at
+  `prev_w −3400 W, grid +4697 W, actual −4144 W, sat_count 2 → 3`: the freeze
+  leaves the integrator at **−176 W**, the slew binds, and the cap drags it to
+  **−2600 W**. It never overrides a *same-cycle* refusal — the freeze clipped
+  `moved` on 75 512 ticks and the slew bound on none of them — but the claim
+  that this placement leaves the frozen path alone is false, and §5 is where
+  that shows up in a committed number.
+* **It is written one-sided, and that is a CLARITY choice, not a correctness
+  one.** ⚠️ **An earlier draft of this file and of the comment in `control.py`
+  said the two-sided band `max(slewed - cap, min(slewed + cap, i_w))` was a bug
+  that would drag a TRAILING integrator up toward the command. That was
+  invented, and the sweep said so: the two spellings agree on 205 920 of
+  205 920 cases** across four tunings, every sign of `prev_w`, `grid_w`,
+  `actual_w` and `i_w`, and the `i_w=None` path. `target` is monotone in `i_w`,
+  so when the slew binds `i_w` lies on the same side of `slewed` as `target`
+  does and the other clamp cannot reach. The one-sided form stays because it
+  NAMES the side the lead is on; the equivalence is recorded so the next reader
+  finds a measurement instead of an argument.
+* **It moves `i_w` and not `target`.** This cycle's command is already decided;
+  what is bounded is what gets CARRIED. That is also why the exhaustive
+  `i_w=None` equivalence sweep in `test_control.py` is untouched — it compares
+  `(target_w, sat_count, frozen, reason)`, none of which this moves.
+* **The cap is in STEPS, not watts**, for SAFETY-39's reason: a watt figure is a
+  constant that outlives the `slew_w` it was derived against. `SLEW_LEAD_STEPS`
+  moves with `slew_limit_w()` and therefore with the rail.
+
+⚠️ **ONE STEP, AND NOT ZERO.** `i_w = slewed` is full back-calculation, and
+`control.py`'s own docstring says what that costs: passing `i_w=None` *"reduces
+this function to the exact velocity form it replaced"*. A zero cap makes `i_w`
+identically the command on every cycle, which is that collapse written from the
+other end. Measured, it is **better** — export 32.02 kWh against 34.07, mean
+quarter −3.69 W against −2.39 — and it is still refused, because it throws away
+the reason the accumulator was split out at all. That 2 kWh is the price of
+keeping the bounded form, and it is stated rather than hidden.
+
+⚠️ **TWO LEADS, AND CONFUSING THEM IS HOW A CHECK GETS WRITTEN WRONG.** The cap
+bounds `i_w − target`, the command this cycle EMITS, at one step — which is what
+makes the unwind one cycle. `Decision.i_w − prev_w`, which is what TEL-10's
+`loop_lead` publishes, is measured against the command the PREVIOUS cycle left
+standing, and the emitted command is itself one step further on: the published
+figure is bounded by **two** steps. Both bounds are asserted, each against its
+own number.
+
+### The two recorded deadlocks, driven rather than argued
+
+`control.py` names two encodings that produce a permanently stuck loop, and a
+gate written on the integrator is exactly the edit that brings them back.
+Neither is reachable here and both are test cases in `test_telemetry.py` part 4:
+
+* **the shrink-only encoding** — *"only corrections that shrink |i_w|"* is
+  unsatisfiable for both signs whenever the correction is larger than twice the
+  integrator, and the loop then sits at its last value forever (measured before
+  the fix: 0 W held indefinitely into a 2 kW import). SAFETY-48 is not a shrink
+  rule; it caps the lead beyond one slew step and only while the slew binds.
+* **`i_w == 0.0`** — `main.py` resets the integrator to exactly 0.0 on every
+  stop and every reseed, and *"may not wind further in the direction it is
+  already pushing"* has no referent there. SAFETY-48 does not touch that gate;
+  the first push from zero is driven and asserted to move.
+
+And a third, specific to this card: **the cap cannot latch.** The flag is not
+carried, and after the cap `|i_w − slewed| = cap`, so the next cycle's command
+covers it in one step and the slew stops binding — after which the integrator
+accumulates freely again. The driven check asserts the command still walks all
+the way to the rail on a railed export.
+
+## 5. What this card COSTS, stated rather than smoothed
+
+**SAFETY-13's release buys back less.** That card's own scenario — a second
+writer holding the pack at +700 W, the command pinned, then released — settles
+at **−800 W** where release/1.0 settled at −1190 W against an integrator of
+−1194 W; and its sibling run settles at **−1200 W** where release/1.0 settled at
+−2390 W. The property AC 4 asserts is unchanged: the released command stops at
+the frozen integrator and not at the rail.
+
+⚠️ **AND THE TWO MOVED FOR TWO DIFFERENT REASONS, WHICH THE ONE-LINE EXPLANATION
+"how far that integrator had been allowed to wind" COVERS ONLY HALF OF.** Gating
+the cap on `not frozen` — one line, `if frozen: _lead_cap = float("inf")`, so
+the cap becomes a no-op while frozen — puts **part 5 back at release/1.0's
+−1190 W exactly**. That run moved because the cap **fires on frozen cycles**
+(§4). **Part 4(b) does not come back**: it is −1200 W gated and −1200 W shipped,
+against release/1.0's −2390 W, because *that* one moved for the winding reason.
+Both literals in `test_control.py` were re-baselined **with the reason beside
+them**, and the second is now asserted against `i_w` rather than against a
+number.
+
+**The alternative that avoids it was measured and rejected.** Gating the cap on
+`not frozen` as above gives export **34.71 kWh** (against 34.07), worst quarter
+**3434 W** (the same as shipped), wasted **3.49 kWh** (against 3.19) — and a
+worst observed lead of **4961 W**, i.e. no bound at all on the quantity this
+card exists to bound. A bound with an exception large enough to drive a truck
+through is not a bound. ⚠️ These four figures replace an earlier set (34.9,
+3461 W, 3.5 kWh, 4966 W) that does not reproduce on this tree with the gate
+spelled as above; the gate spelling is written out here so the next reader can
+re-run it rather than re-derive it.
+
+**One quarter-hour in 1534 is 532 W worse.** The billed figure is a MAXIMUM, and
+at the fitted plant lag the maximum improves (3739 → 3434 W); no quarter under
+SAFETY-48 reaches release/1.0's own worst. The mean moves the right way. The
+tail is reported because a maximum over 1534 quarters is decided by one of them
+— and §3a is the reason that improvement is not claimed as a benefit of the
+card: at every shorter plant lag release/1.0's own maximum is already 3434 W.
+
+## 6. The independent confirmation, which arrived as a failing check
+
+`test_control.py`'s SAFETY-39 section drives a family of 51 synthetic export
+steps through a **first-order plant this file writes itself** — no relation to
+the replay, no recorded data in it at all. It carried this assertion:
+
+> ⚠️ THE SLEW DOES NOT OWN THE OVER-ABSORPTION … Quartering the slew from 1000
+> to 250 does not reduce the over-absorption at all
+
+and it was right about the mechanism and therefore wrong about the conclusion:
+`slew_w` bounds the OUTPUT while the integrator accumulates `gain · error`, so a
+slower slew left the integrator winding for longer. Worst case over the family:
+
+| `slew_w` | release/1.0 | this branch |
+|---|---:|---:|
+| 1000 | 1005 W | **729 W** |
+| 0 (the rail, 556) | 1109 W | **550 W** |
+| 400 (the live interim) | 1285 W | **424 W** |
+| 250 | 1330 W | **326 W** |
+
+**The ranking inverts.** Before: slower is worse, monotonically. After: slower is
+better, monotonically. Two plant models that share nothing agree on the sign,
+which is worth more than either alone — and it means SAFETY-39's *"gain is the
+next constant to re-derive"* is now only half true: with the lead bounded, the
+slew owns a share of the over-absorption it did not own before. `gain` is still
+not touched here, for SAFETY-39's own reason: two live control-law constants
+moving in one release makes the next measurement uninterpretable.
+
+⚠️ **AND THE RIG SAYS THE SAME THING, WHICH MEANS TWO COMMITTED TRANSCRIPTS
+CHANGED MEANING UNDER THIS CARD.** `tools/slew_sim.py --slew` runs the same
+derivation on admin/goodwe's `plantsim.Plant`, a third model again. Worst-case
+over-absorption over its 51-step family, `slew_w` from 1000 down to 250:
+
+| `slew_w` | 1000 | 800 | 700 | 600 | 556 | 500 | 400 | 300 | 250 |
+|---|---:|---:|---:|---:|---:|---:|---:|---:|---:|
+| release/1.0 | 958 | 1107 | 1133 | 1058 | 987 | 1029 | 1150 | 1143 | 1081 |
+| **this branch** | 777 | 734 | 663 | 563 | 553 | 507 | 435 | 358 | 321 |
+
+release/1.0's row is flat and non-monotone and **800 really is better than 556**
+on that column — SAFETY-39 measured it correctly and its §3 sentence is true of
+the law it was written against. This branch's row falls monotonically. So
+SAFETY-39's record is not retracted; it is given a **forward reference**, and
+`slew_sim.py`'s own narration now reads `SLEW_LEAD_STEPS` out of the control law
+it imported and says which of the two tables it is printing. MUTATION.md habit 8
+— a committed transcript is a check, and a transcript whose prose contradicts
+its own table is a failing one.
+
+## 7. Verified by breaking it
+
+**The law.** `test_telemetry.py` part 4 and `test_control.py`'s SAFETY-39
+section. The mutation table is in `test_telemetry.py`'s header.
+
+**The instrument** (MUTATION.md habit 8 — anything under `tools/` that a
+document quotes is subject to the battery):
+
+| # | mutation to `app/control.py` | what the instrument did |
+|---|---|---|
+| I2 | the whole SAFETY-48 block deleted | **REFUSED**, exit 1, `NOTHING HAS BEEN MEASURED` — not a zero delta |
+| I3 | the anchor line itself edited | **REFUSED**, same message |
+| I3b | `SLEW_LEAD_STEPS = 1000` — the cap present but inert | **every row +0.00**, which is the honest report that the block is doing nothing |
+| I4 | `SLEW_LEAD_STEPS = 0` — full back-calculation | every row moves further; this is the rejected form's number in §4 |
+
+I3b is the one that matters: it proves the delta in §3 is caused by the block
+and not by the two runs differing for some other reason.
+
+**The law**, driven in the CI image on a purged tree, fingerprinted before,
+after and after the revert:
+
+| # | mutation to `app/control.py` | bytes | reds |
+|---|---|---:|---|
+| L1 | the whole SAFETY-48 block deleted | −195 B | 5 in `test_telemetry.py`, 4 in `test_control.py` |
+| L2 | `SLEW_LEAD_STEPS = 0` — the velocity form | +0 B | 4 + 3 |
+| L3 | `SLEW_LEAD_STEPS = 12` — a cap above the rail | +1 B | 4 + 3 |
+| L4 | the cap applied unconditionally, outside the slew branch | −92 B | 1 + 0 — **and it was a SURVIVOR of all thirty files before that check existed** |
+| L5a | the `min`/`max` FUNCTION names exchanged | +0 B | 5 + 5, one of them `test_control.py`'s own "frozen integrator never deadlocks" over 13 041 states |
+| L5b | the two BRANCH BODIES exchanged — the other reading of "the cap on the wrong side" | +0 B | 5 + 4, and it does **not** reach the deadlock sweep |
+| L6 | the lead measured against `prev_w` rather than the command emitted | +0 B | 6 + 3 |
+
+⚠️ **L5 AND L6 ARE BOTH ZERO BYTES** — `min`/`max` and `slewed`/`prev_w` are
+each the same length — so no fingerprint and no byte delta can see either, and
+one of L5a's reds is `test_control.py`'s own *"frozen integrator never
+deadlocks"* sweep over 13 041 states, written by SAFETY-13 for a different
+reason.
+
+⚠️ **THREE OF THESE COUNTS WERE WRONG AND ARE RE-MEASURED ABOVE, WHICH IS
+MUTATION.md's REPORTING RULE 3 APPLIED TO THIS CARD'S OWN TABLE.** The earlier
+row gave L5 as 2 + 5 and L6 as 4 + 3; driven again in the CI image on a `cp -a`
+of this tree, purged, `:ro`, one file at a time, they are **5 + 5** and
+**6 + 3**. ⚠️ **AND "L5" NAMED TWO DIFFERENT MUTATIONS.** "`min`/`max` swapped"
+can mean the function names exchanged or the branch bodies exchanged; they are
+both red, they are both the cap on the wrong side, and they give different
+counts (5 + 5 against 5 + 4) and reach different checks. A row that writes one
+number for a mutation a reader cannot re-derive from its own description is a
+row that cannot be re-run, so both spellings are listed. The directions in the
+original table were all correct; the counts were decoration, and decoration in
+a mutation table reads as evidence.
+
+## 7b. The transcript, quoted rather than summarised
+
+`python3 tools/replay_recorded_loop.py --sensitivity`, on this branch, 58 s:
+
+```
+THE RECORDING: 256252 meter instants over 16.00 days, loop-2026-09-02_2026-09-17
+    tick   p5 4.77 s   median 5.01 s   p95 7.86 s   (control.LOOP_TICK_S says 2.0)
+    the recorded command: extremes -5000 / +5000 W  ->  max_w 5000;  most common step above 100 W is 400 W, 9924 times  ->  slew_w 400
+    the fitted inverter: lag 7.5 s, tau 2.0 s, batt = 0.9731 x cmd -22.4 W, residual 375 W RMS above the SoC floor
+
+FIDELITY - the BEFORE law replayed against the recording it came from
+    setpoint  r=0.887  mean     +601 W simulated vs     +739 W recorded
+    grid      r=0.682  mean     +195 W simulated vs     +239 W recorded
+    export       39.61 kWh simulated vs    29.43 kWh recorded  ->  the model is +35 % PESSIMISTIC about the loop's tracking
+
+THE A/B, same ticks, same disturbance, same plant, same seed
+                                 release/1.0     SAFETY-48       delta
+    export kWh                         39.61         34.07       -5.54   the cost
+    import kWh                        116.07        111.20       -4.86
+    battery sign reversals           2992.00       2770.00     -222.00
+    wasted throughput kWh               4.67          3.19       -1.48
+    worst 15-min offtake W           3738.67       3433.94     -304.74   ⚠️ THE BILLED ONE
+    recovery events                   549.00        612.00      +63.00
+    recovery median s                 232.06        199.04      -33.01
+    recovery p99 s                    849.00        849.94       +0.94
+    recovery max s                    901.06        898.40       -2.66
+    unrecovered (>900 s)               53.00         31.00      -22.00
+    |i_w - prev_w| p99 W             3361.12        800.00    -2561.12
+    |i_w - prev_w| max W             9200.00        800.00    -8400.00
+    slew-limited ticks              16392.00      11654.00    -4738.00
+    mean quarter delta W                                         -2.39   over 1534 quarters
+    worst quarter delta W                                      +532.27
+
+SENSITIVITY - the ranking, not the watts
+      variant                               export kWh           worst quarter W   mean quarter dW
+      plant lag 5.0 s                32.1 ->     27.2         3434 ->     3434             -1.02
+      plant lag 10.0 s               75.4 ->     68.3         3954 ->     3434             -4.65
+      plant tau 8 s                  56.5 ->     49.8         3995 ->     3605             -3.30
+      gain 1.0135, offset -26        46.8 ->     39.3         3713 ->     3434             -3.27
+      slew_w 555.6 (the rail)        36.5 ->     34.4         3434 ->     3434             -0.17
+      gain 0.3                       28.1 ->     27.0         3434 ->     3434             +0.16
+
+    (58 s)
+```
+
+⚠️ **`--sensitivity` IS THE RANKING AND NOT THE WATTS.** The export figure moves
+by a factor of two across these plants; what does not move is the direction —
+**on export**. ⚠️ **THE `worst quarter W` COLUMN IS NOT THE SAME KIND OF
+EVIDENCE AND THIS PARAGRAPH USED TO TREAT IT AS IF IT WERE.** Three of its six
+rows read `3434 -> 3434`, and that is not "the direction holds": it is
+release/1.0 *already sitting at 3434 W* on those plants, with nothing for the
+card to improve. §3a sweeps the lag properly and finds the same thing at every
+lag ≤ 5.0 s. The billed-quarter improvement in the A/B table above exists at one
+plant, the one `fit_plant()` selects by an objective that separates it from its
+neighbour by 0.3 %.
+
+Two rows deserve naming rather than rounding: at `slew_w: 555.6` (the rail) and
+at `gain: 0.3` the mean quarter-hour delta is −0.17 W and **+0.16 W** — ties,
+not improvements. Both are regimes where `|error| > slew_w / gain` is rarely
+satisfied (1333 W at `gain: 0.3`, 926 W at the rail against a measured median
+onset error of 1114 W), so there is little for the card to bite on. That is the
+mechanism agreeing with itself, and it is also the honest answer to "would this
+still be worth shipping if the tuning moved": at `gain: 0.3` it would not be.
+
+## 8. What this card does NOT establish
+
+* **Nothing here drives an inverter.** The replay is a model with a 375 W
+  residual and no arbiter in it. The closed-loop answer comes from the rig or
+  from a live run — SAFETY-47 records why a shadow run cannot give it.
+* **The live tick is 5.0 s, not `LOOP_TICK_S`'s 2.0 s**, measured off 9924
+  recorded 400 W steps and off the meter's own cadence. It is wrong in the SAFE
+  direction (a slower meter makes `validate.py` rule 10 conservative) and is NOT
+  changed here — re-deriving `SLEW_RAIL_FRAC` is a refusal boundary on a live
+  install and belongs to its own card. It is recorded in the tool's header and
+  printed on every run.
+* **The brief's plant figure was close but not exact.** It quoted
+  `delivered = 1.0135 × command − 26 W, r = 0.992` at a 4–6 s publish lag. On
+  this 16-day window, above the SoC floor, the same relation measures
+  `1.00 × command − 28 W, r = 0.977` at a best-fit pure delay of **7.5 s**. The
+  conclusion — the inverter is a pure follower and the plant is not the problem
+  — survives; the coefficients are the ones in §2.
+* **The brief's cost figure is larger than this measurement.** It quoted ~14 kWh
+  of avoidable export and 65 % of site export inside 7.9 % of the time. Measured
+  here: **5.5 kWh** avoidable of 39.6 kWh modelled (29.4 kWh recorded), with
+  42 % of export inside the 6.3 % of ticks that are slew-limited and 69 % within
+  ±60 s of one, over 15.3 % of the time. The concentration claim holds; the
+  avoidable-kWh figure does not, and the difference is not reconcilable from
+  here because the reconstruction it came from was discarded.

goodwe_controller/DECISIONS/SAFETY-56-what-the-gate-cannot-tell-apart.md

@@ -0,0 +1,181 @@
+# SAFETY-56 — what the gate cannot tell apart, said in the sentence
+
+**Text only. No behaviour changes in this card**, and §5 is the measurement that
+says so: the same stimuli through the tree before and after produce a
+**byte-identical** trace of every verdict, every `reading()`, every `inputs_ok`
+and every readiness row's `(ok, warn)`.
+
+---
+
+## 1. The defect
+
+0.10.1 is regulating a real GW5000S-BP. Two messages tell the operator that
+healthy hardware has failed.
+
+**The log line**, as emitted on the reference site on 2026-09-21:
+
+> SAFETY-37: inverter-a battery-power register **is not following its own
+> command** - STALE_READING: -3 unchanged for 36 s while the standing command
+> moved 800 W to +1600 W - **the reading is not following**, so it is reported
+> as MISSING rather than as a measurement … Treating it as MISSING, which
+> commands 0 W.
+
+**The readiness row**, at the same moment:
+
+> NOT READY — battery power: `sensor.kelder_goodwe_master_stage1_goodwe_inverter_ac_power`
+> **is missing or not numeric**
+
+That entity was present, numeric and updating.
+
+**SAFETY-37's conjunction is correct and is not touched by this card** —
+`unchanged > 35 s AND |command| > 250 W AND |travel| > 250 W`. A register
+genuinely stuck against a real command is exactly what it should catch, and a
+pack that cannot comply is a state the site must stop in too. What was wrong is
+what the sentences **concluded** from it.
+
+## 2. Two worlds satisfy the conjunction
+
+| | the register | the pack |
+|---|---|---|
+| **DEAD** | has stopped reporting reality | is doing what it was told |
+| **REFUSED** | is reporting reality correctly | cannot comply — the BMS is refusing at its floor |
+
+A refused pack holds still under any setpoint, so an honest register publishes
+the same unchanged number a dead one does. **Nothing `freshness.py` is handed
+separates them.** All three sentences asserted DEAD.
+
+## 3. The live episode was REFUSED, and it is measured, not argued
+
+Off the committed capture `scenarios/safety57-2026-09-21/bus-a-2026-09-21-1030-1110.log.gz`,
+whose bytes and decoder are already graded by `test_freshness.py` part 10a:
+
+| | |
+|---|---|
+| the register | answered **-3 W for 850 s**, 10:51:24 → 11:05:34 |
+| the commands during that hold | **+260, +660, +1060 W** — discharge only, never a charge |
+| pack SoC throughout | **11 %** |
+| first **charge** command after the restart | 11:05:31 at **-400 W** |
+| the register moves | **11:05:34** — **3 s**, inside one 17.0 s obligation window |
+
+**A register that answers a reversed command inside one obligation window had
+not stopped reporting.** What would not move was the pack. The sentence the
+operator read named the one thing in the loop that was telling the truth.
+
+⚠️ What this does **not** establish: that no register is ever intermittently
+wrong. It excludes a register that had simply stopped; it cannot exclude one
+that was wrong and then right. That is the point — the new sentence claims
+neither.
+
+## 4. The fix, and why it is three sentences and not one helper
+
+Each message states **what was observed** and names **both** explanations.
+
+| where | before | after |
+|---|---|---|
+| `app/freshness.py` `_grade()` | *"…+1600 W - the reading is not following, so it is reported as MISSING…"* | *"…+1600 W. **TWO THINGS LOOK LIKE THIS AND THIS GATE CANNOT TELL THEM APART**: the register may have stopped reporting reality, or the source may be unable to comply with the command - a pack the BMS is refusing holds still under any setpoint, and an honest register then reads exactly like a frozen one. Either way the number cannot be read as this command's effect, so it is reported as MISSING…"* |
+| `app/main.py` `_read_unit()` | *"SAFETY-37: %s battery-power **register is not following its own command** - %s."* | *"SAFETY-37: %s battery-power reading **did not move under a command that did, WHICH IS NOT BY ITSELF A VERDICT ON THE REGISTER** - %s."* |
+| `app/main.py` `checks()` | *"{label}: {entity} **is missing or not numeric**"* | *"{label}: **no usable value this cycle from** {entity} - **and this row cannot tell which of two things that is**: the entity is missing or not numeric, or it is publishing a number that this controller is withholding (a freshness gate does exactly that, and names itself in a row of its own). Confirm the entity in Developer Tools before replacing it"* |
+
+**Three sentences, three wordings, no shared helper.** The first two are a log
+line about a **behaviour**; the third is a banner about a named **entity**, and
+the two answer different questions ("what did the register do" against "can I
+trust this entity"). A helper serving both would have to drop whichever half
+the other caller does not need, and the half it dropped would be the
+operator's next step. The log line names the pair **once**, inside the `%s` it
+already interpolates, rather than in both of its own halves.
+
+**No new input, and SoC is not wired.** `BOUNDS["soc"]` stays *STATED, NOT
+WIRED*; telling the two worlds apart needs the pack floor (SAFETY-32's number)
+and SoC (TEL-08's wiring), and a message honest about its own ambiguity needs
+neither. Part 11b drives the two worlds at **50 %** and **11 %** SoC and
+asserts the sentence does not move one byte.
+
+**The readiness row does not branch.** `inv.batt_fresh.stale` is on the same
+object at the same moment, and the row deliberately does not ask it: the same
+loop renders the grid and SoC rows, which have no gate, and a branch per row
+would be a second place where "why is this None" is decided. The gate already
+has a surface — `stale_note()` rides `liveness_notes()` a few rows below with
+the whole STALE_READING sentence in it — so the operator's discriminator is
+*"is that row there?"*, and part 11d asserts that row is **present in REFUSED
+and absent in ABSENT**.
+
+## 5. Behaviour is byte-identical, measured
+
+`tools/safety56_behaviour_trace.py` prints two documents from one stimulus set.
+The `behaviour` half contains **no sentence**: only `stale`, `reading()`,
+`releases`, `held`, the window bookkeeping, `inputs_ok`, and every readiness
+row's `(ok, warn)`. Run in the CI image, purged, `:ro`, against
+`origin/release/1.0` **archived out of git** and against this branch:
+
+| | |
+|---|---|
+| the committed live capture | **2390 reads**, 7 verdict edges |
+| a swept grid of command × register schedules | **66 cells × 120 reads** — 1060 stale reads, 1309 `MISSING` readings, 6 releases |
+| six driven controller worlds through the shipped read path | DEAD, REFUSED, ABSENT, HEALTHY, RELEASE, RETRIP — every read's `(batt, inputs_ok, stale)` and every `checks()` row's `(ok, warn)` |
+| **result** | `6030175ed2ab9a4143e86e89a71d45c8ab041ac1c00121a3e3e023cd2b08996c` **on both trees** |
+
+⚠️ **AND THE CONTROL IS INSIDE THE TOOL, BECAUSE AN IDENTITY BETWEEN TWO TREES
+THAT ARE THE SAME TREE IS HABIT 4.** `--compare` refuses to report "behaviour
+unchanged" unless the `sentences` halves **differ**. This card's first
+invariance run was exactly that mistake — it archived a branch whose edits were
+not committed yet, so `before` and `after` were the same code and the identity
+was perfect and worthless.
+
+Both of the tool's refusals are **driven**, not asserted:
+
+| | |
+|---|---|
+| the same file compared with itself | `REFUSED: the sentences halves are IDENTICAL…`, exit **2** |
+| `MOVE_W` 250.0 → 240.0 in the after tree | `BEHAVIOUR MOVED at 'sweep_stale_reads' / 'sweep_missing_reads' / 'sweep_trace'`, exit **1** |
+| this card | `OK: sentences differ, behaviour is byte-identical.`, exit **0** |
+
+## 6. The mutation battery
+
+Each in its own `mktemp`'d copy (habit 18), purged on the host, mounted `:ro`,
+graded by `tools/mutation_run.sh` in the CI image.
+
+| | mutation | Δ bytes | named reds |
+|---|---|---|---|
+| M1 | `_grade()` reverted to *"the reading is not following"* | -402 | **3** |
+| M2 | the log line reverted to *"register is not following its own command"* | -80 | **2** |
+| M3 | the row reverted to *"{entity} is missing or not numeric"* | -619 | **2** |
+| M4 | *register* and *source* transposed between the two explanations | **0** | **1** |
+| M5 | the second explanation deleted, the first kept | -216 | **1** |
+| M6 | *"CANNOT TELL THEM APART"* replaced by *"IN ORDER OF LIKELIHOOD"* | -13 | **1** |
+| M7 | the REFUSED world's ground truth set to the DEAD world's | 0 | **2** |
+| M8 | the row's second cause deleted | -309 | **1** |
+| M9 | `label` and `entity` transposed in the row | **0** | **3** |
+| M10 | M1 + M2 + M3 together, i.e. exactly what 0.10.1 ships | -1101 | **5** |
+| M11 | the accusation literals replaced by one that matches nothing | 0 | **1** |
+
+⚠️ **M9's first run was a defect in this card's own check, and it is the one
+worth reading.** The row was fetched with `[...][0]`. Transposing `label` and
+`entity` makes the row unfindable, so the run died on an `IndexError` — a red
+with **no name attached**, with every check after that line **ungraded**. That
+is FCST-06's shape exactly. `_s56_row()` now returns a named absence instead of
+raising, and a precondition grades it: **0 named reds before, 3 after.**
+
+⚠️ **M11 is the other one aimed inward.** `not any(...)` over an empty list is
+True, and so is one over three mistyped literals. The positive control runs the
+same predicate against the three sentences **as 0.10.1 shipped them** and
+requires it to find an accusation in every one, and every literal to match at
+least one of them (habit 7: vary one thing from an accepted baseline).
+
+## 7. What part 11 does not grade
+
+* It does not show the live episode was a BMS refusal beyond doubt — see §3.
+* It does not grade English. A sentence that named both explanations and then
+  said something useless about them would pass.
+* The `no entity configured` branch beside the rewritten row is untouched and
+  ungraded: a blank entity really is the only thing it can be.
+* The **grid-power and battery-SoC rows** go through the same rewritten line and
+  have no freshness gate today, so for them the second cause is a hypothesis
+  about this controller rather than a live possibility. That is weaker than the
+  battery-power case and is the price of not branching per row. A gate on either
+  signal — TEL-08 would be one — makes it exact.
+* **SAFETY-58 is not touched** (the first read after a long rest trips before a
+  healthy register could answer), and neither is the 710/790 disagreement
+  between `test_freshness.py` and the changelog. Both are separate cards; the
+  second has a **fourth site** at
+  `DECISIONS/SAFETY-57-the-exit-from-a-stale-verdict.md:274` that a fix written
+  off the PR table alone would miss.

goodwe_controller/DECISIONS/SAFETY-57-the-exit-from-a-stale-verdict.md

@@ -0,0 +1,388 @@
+# SAFETY-57 — the stale-reading verdict gets an exit, because its own consequence is what stopped it being tested
+
+**Status:** decided and implemented on branch `SAFETY-57`, off `origin/master` @ `6f5e8e3`
+(content-identical to `release/1.0` @ `8a57361`).
+**Card:** SAFETY-57 — *"the freshness gate has no exit reachable from inside the state it creates"*.
+**Nothing here reached the inverter.** No contact was made with 192.168.2.158 or
+192.168.2.221. The one live system touched is `sniffer@192.168.2.167`, a
+**passive** RS-485 listener with no address on the bus, and it was read only.
+
+---
+
+## 0. The five things a reader should take away
+
+1. **The live episode is reproduced from the wire, not modelled.** The capture
+   is committed, the decoder is committed, and the box that produced it was
+   running the defect — so the `0 W` in the trace *is* the add-on's own
+   `inputs missing → command 0 W`. §2.
+2. **Option 2 from the card — "do not arm the gate when the command is 0 W" —
+   already holds, and it is not the bug.** `_grade()` has required
+   `|standing| >= MOVE_W` since SAFETY-37. The trip happened at **+1060 W** and
+   the stuck state is at **0 W**; they are different moments. §3.
+3. **The decision is not "how long", it is "when".** The verdict is withdrawn
+   when the **obligation that produced it is no longer standing** — SAFETY-13's
+   shape one module over. The 17.0 s is the obligation window that was already
+   derived in the file, taken at the **floor** of its band, and which half is
+   safe is the **opposite** of SAFETY-13's. §4.
+4. **It costs 52 % exposure on a permanently dead register, and that number is
+   in the suite so it cannot be forgotten.** It is payable only because one
+   re-grading window (35 s) is shorter than both consumer holds (75 s, 85 s).
+   **No detection SAFETY-37 had is given back.** §5.
+5. **The battery had been rescuing this code by accident.** 93 trips in the
+   committed 16-day capture; median wait for the BMS keep-alive pulse that
+   cleared them **143 s**, worst **5 h 57 m**. §6.
+
+---
+
+## 1. What was there, in the terms the code uses
+
+`freshness.py`, `Freshness.submit()` and `_grade()`:
+
+```python
+if self.changed_mono is None or value != self.held:
+    ...
+    self.stale = False          # the only place the latch is cleared
+def _grade(self, standing_w, now_mono):
+    if self.stale or self.changed_mono is None:
+        return                  # sets the latch; never clears it
+```
+
+and `main.py:1777`, `inv.batt = inv.batt_fresh.reading()`, where `reading()`
+answers `None` while `stale`. `inputs_ok` sees the `None`, the site holds for
+`stale_input_s`, then files `Claim.set("safety", P_SAFETY, 0.0, "inputs
+missing")` and keeps filing it.
+
+The reason the latch exists is written in the class docstring and it is a good
+one: without it the verdict oscillates at about 1 Hz, because declaring the
+reading stale drops the command below `MOVE_W`, which un-arms the conjunction,
+which hands the held number straight back.
+
+**The defect is that the only thing that ends it is an arrival carrying a
+different number — and the state's own output is what stops the register being
+asked for one.** The log line promised the opposite, in the same sentence that
+announced the 0 W:
+
+> *Treating it as MISSING, which commands 0 W. It clears itself the moment the
+> register reports a different value.*
+
+---
+
+## 2. Reproducing it, from the wire
+
+`scenarios/safety57-2026-09-21/bus-a-2026-09-21-1030-1110.log.gz` is 3840
+verbatim frames off the RS-485 pair, 10:30–11:10 Europe/Brussels, decoded by
+`tools/decode_bus_capture.py`. The decoder reports **0 unparsed, 0 bad CRC,
+0 unknown shapes**, and its mode→sign convention is **graded off the capture**
+rather than trusted: 298 commands at or under −1000 W are each answered one
+obligation window later by a negative register reading, and not one positive.
+
+| capture time | on the wire |
+|---|---|
+| 10:51:14 | `0x0518` = **−447 W**; the loop is charging |
+| 10:51:19 | the command reverses: EMS **mode 3**, 260 W of discharge |
+| 10:51:24.7 | `0x0518` = **−3 W**. The pack is at **11 %**, the BMS refuses the discharge, the inverter idles. **The register is healthy and truthful.** |
+| 10:51:29.7 | the command reaches **+1060 W**. 800 W of travel |
+| 10:52:21.7 | the setpoint is written **0 W** — this is the add-on's own §11.1 rule 1, recorded on the wire |
+| …850.0 s | `0x0518` does not change value |
+| …790.0 s | the setpoint does not change value |
+| ~11:04 | **a person restarts the add-on** — not visible in this file, and the only thing that ends the episode |
+| 11:05:31.7 | the restarted loop commands **−400 W of charge**, which the pack accepts at 11 % |
+| 11:05:34.7 | `0x0518` = **−137 W** |
+
+⚠️ **THE CAPTURE IS CLOSED-LOOP FOR THE WHOLE PARKED INTERVAL**, which is why
+this is a reproduction and not a simulation: the box was running 0.10.0, so
+every command in the trace is the shipped code's own. The only event inside the
+window the file cannot account for is the human restart.
+
+Replaying the shipped `_read_unit` loop at 1 Hz against those two series
+(`test_freshness.py` part 10b):
+
+| | stale at | clear at | parked |
+|---|---|---|---|
+| **before** (`release_s = inf`) | 10:52:00 | 11:05:35 | **815 s**, and `reading()` is `None` on all **812** reads from the trip to the first command a human put on the wire, with the register at −3.0 W in every one of them |
+| **after** | 10:52:00 | **10:52:39** | **39 s**, with `0x0518` still answering the same **−3 W** |
+
+⚠️ **THE COUNTERFACTUAL IS `release_s = inf`, AND IT IS GRADED RATHER THAN
+CLAIMED.** With an infinite bound `_release()` never fires, `_open_window()` is
+only ever called where the register moves, and the window pair is the
+change-stamp pair — byte-for-byte the pre-SAFETY-57 conjunction. Part 10b
+asserts that by driving part 1's own fresh/stale pair through both bounds and
+comparing the verdict streams.
+
+The replay also found a **one-read trip at 10:48:14** that clears one second
+later. That is a pre-existing false positive and it is now recorded as
+survivor 5 — §7.
+
+---
+
+## 3. What the card's option 2 actually buys, which is nothing here
+
+The card offered *"do not arm the gate when the command being graded is 0 W"*
+and warned that it might hold already. **It does, and it has since SAFETY-37**:
+`_grade()` returns at `abs(standing_w) < self.bound.move_w`, and
+`test_freshness.py` part 4 has a named check on that term, added because a
+mutation removing it survived.
+
+The warning in the card is the right one and it is worth writing down: **the
+trip and the stuck state are different moments.** The gate armed at **+1060 W**,
+where the conjunction is entirely correct — a command travelled 800 W and the
+register did not move for 35 s. The site then went to **0 W** *because of the
+verdict*. An entry-side rule cannot reach a state that is entered legitimately
+and then persists. **The defect is the exit, and nothing else in the conjunction
+is touched by this card.**
+
+Option 3 — probing with a small non-zero command — was not taken and does not
+need to be. It writes to a real actuator to test an assumption, and §4's rule
+does not need a probe: the site's *normal* control resuming is the test, and it
+is gated behind the same `inputs_ok` everything else is.
+
+---
+
+## 4. The decision: which verdicts get an exit, and what the bound is
+
+> The stale verdict holds as before, **unless** the obligation that produced it
+> is no longer standing — `|standing| < MOVE_W` — **and** it has been gone
+> longer than the register would have needed to answer it. On a release the
+> latch clears and a **new grading window** opens at that instant.
+
+This is [[SAFETY-13]]'s §4 in a different module, and deliberately so: that card
+established the house answer to "a latch with no exit" and its answer was *not*
+a plain time bound but a **predicate plus a time bound**, where the predicate
+says whether the state can end on its own. Here the predicate is that **the
+question is no longer being asked.** A register under a 0 W command is obliged
+to be nowhere, so a verdict about whether it is following cannot be tested, and
+a verdict that cannot be tested may not stand for ever.
+
+### 4.1 Why the window has to re-open, and what happens if it does not
+
+`_grade()` compares the register's unchanged time against `unchanged_s` and the
+command's travel against the command standing when the window opened. If a
+release cleared the latch **without** re-opening the window, the first read at
+which the resumed command travels 250 W would re-trip immediately — the
+register would never get the 17 s in which it could answer, and the live
+episode's recovery (a charge the pack **accepts**) would be killed inside two
+seconds. Mutating exactly that (`graded_from` re-anchored to `changed_mono`,
++82 B) takes four named checks red.
+
+The new window is `BATT_UNCHANGED_S` = **35 s**, the same bound as entry,
+because it is the same question — *does this register follow the commands issued
+from now on?* — and there is no principled shorter answer to it. It is also the
+number the exposure argument in §5 rests on, so it is not free to move.
+
+### 4.2 `RELEASE_S` = `BATT_OBLIGED_S` = 17.0 s, and which half is safe
+
+The quantity needed is *has the register had its chance to answer the command
+standing now?*, and `freshness.py` already derives it as the floor of
+`BATT_UNCHANGED_S`'s band:
+
+```
+6.0 s   plant          goodwe/NOTES.md §5.9, measured 2026-08-22
+10.0 s  publisher      firmware/goodwe-master.yaml:181, update_interval: 10s
+1.0 s   this add-on    run_control()'s await asyncio.sleep(1)
+```
+
+⚠️ **IT IS THE FLOOR OF ITS BAND, NOT A SENSITIVITY PREFERENCE** — the mirror of
+`MOVE_W` taking the **ceiling** of its own for the mirrored reason.
+
+| | the question | the safe half | why |
+|---|---|---|---|
+| SAFETY-13's `SETTLE_CYCLES` | may the plant still be the **explanation**? | the **longer** half | a shorter bound stops believing the plant too early, and then it accuses |
+| this one | may the verdict still be **tested**? | the **shorter** half | being wrong *long* is the failure being fixed; being wrong *short* costs one re-grading window, and §5 bounds that |
+
+Below 17.0 s the release pre-empts the **cheaper exit** — the register answering
+the new 0 W command by itself, which clears the latch on evidence rather than on
+a timer. That is graded behaviourally rather than asserted: a register that
+answers at +16 s clears by **movement** at `release_s = 17.0` with `releases`
+still 0, and by **timer** at `release_s = 5.0`.
+
+The family is computed and printed (habit 10): `5, 16, 17, 18, 35, inf` give
+six distinct release instants, so no check in the file can confuse two of them.
+
+### 4.3 Two clocks, and the operator reads the register's
+
+`changed_mono` / `unchanged_s()` remain facts about the **register**: after a
+release they go on reporting that it has not moved for 850 s, because it has
+not. `graded_from` / `graded_s()` are the **verdict's** window. They coincide
+until the first release. Collapsing them either lies to the operator or defeats
+the re-grading, and both directions are mutated red.
+
+The stale sentence's `unchanged for N s` slot carries the **register's** number;
+a re-trip appends a clause naming the window and the grade count, so the two
+durations cannot be read as one number that moved (habit 14).
+
+---
+
+## 5. What it costs, measured
+
+Driven against a register frozen for good, 1201 reads, shipped defaults
+(`test_freshness.py` part 10c):
+
+| | parked | the held number reaches a consumer | releases |
+|---|---|---|---|
+| before | 1166 s | **35 reads (2.9 %)** | 0 |
+| after | 571 s | **630 reads (52.5 %)** | 17 |
+
+⚠️ **52 % IS PAID EVERY CYCLE, NOT OCCASIONALLY.** The period is
+`stale_input_s` (15 s) + `RELEASE_S` (17 s) parked, then one 35 s window.
+
+It is payable because of one inequality, and it is the inequality
+`test_freshness.py` part 6 has graded against the shipped `config.yaml` since
+SAFETY-37:
+
+```
+35 s  (the re-grading window)  <  75 s  (circulation_hold_s)  <  85 s  (unit_sign_disagree_s)
+```
+
+Every unbroken run of exposure is **exactly one window**, so neither consumer
+can reach a verdict inside one, and the re-trip that ends each run hands them a
+`None`, which **clears** their windows rather than accumulating into them.
+
+**And nothing SAFETY-37 detects is given back**, which is the half that makes
+this a trade rather than a regression: a permanent `None` clears those same two
+windows for ever as well, so on the shipped-before module those detectors are
+*equally* unable to speak about the unit. What the held number does reach for
+35 s is `site_batt_w`, the anti-windup input of `control.compute()` — which
+answers a large unexplained divergence by **freezing the output**, the
+conservative direction and SAFETY-13's business — and the command itself is
+derived from the **P1 meter**, never from `batt`.
+
+### 5.1 The narrowing this does NOT take, named so the next card can
+
+The live episode's register refused a **discharge** into an 11 % pack and then
+followed a **charge** three seconds later. A refusal in one direction is not
+evidence about the other, and a gate that knew the pack's floor could re-grade
+on the first command that crosses it instead of on a timer — which would shrink
+the 52 % above. That needs SoC, which this module deliberately does not take
+(see the `soc` row and TEL-08), and the pack floor, which is SAFETY-32's number.
+It is **not needed to give the state an exit**, and folding it in here would
+make the exit depend on a second measurement being right.
+
+---
+
+## 6. The measurement that says the old exit was luck
+
+`scenarios/loop-2026-09-02_2026-09-17/` replayed at 1 Hz through the shipped
+conjunction (`test_freshness.py` part 8b): **93 trips in 16 days.** The only
+thing that could clear any of them was the register carrying a different number,
+and that took:
+
+| | |
+|---|---|
+| minimum | 0.6 s |
+| **median** | **143.4 s** |
+| maximum | **21440.1 s** (5 h 57 m) |
+| at or over the live episode's 710 s | **17 of 93** |
+
+The short waits are the BMS keep-alive pulse — SAFETY-50 measured its ceiling at
+508 W — twitching `0x0518` and satisfying the clearing rule **by accident**.
+Over a fifth of the trips are cleared in under 20 s by something nothing in this
+add-on asked for.
+
+⚠️ **WHAT THAT REPLAY IS AND IS NOT.** The capture runs 2026-09-02…17 and
+0.10.0 — the first version carrying this gate — was cut on 2026-09-16, so the
+setpoint column is an **ungated** controller's. That makes each trip an honest
+register-versus-command divergence off the real bus, and it makes the post-trip
+command column something a gated box would **not** have written. The figure
+taken from it is therefore the only one that does not depend on the command at
+all — how long this register goes without changing value — and it **under**-states
+the wait, because a site parked at 0 W gives the register even less reason to
+move than the one recorded here.
+
+---
+
+## 7. Survivors, and the two things the battery found
+
+The battery is 22 mutations over `app/freshness.py`, `app/main.py` and
+`tools/decode_bus_capture.py`, plus one over the committed capture itself. All
+run through `ci_run.sh`, a mirror of `checks.yml`'s own step: a purged copy of
+the tree, bind-mounted `:ro`, one file at a time, `PYTHONDONTWRITEBYTECODE=1`.
+Per MUTATION.md habit 18 the harness's scratch file is `mktemp`ed per
+invocation and the tree is fingerprinted **after the revert** as well as before;
+every revert restored the recorded sha256 and byte count.
+
+**21 red, 1 argued equivalent, 0 unexplained survivors.** The table is in the
+PR body. Two of them are worth keeping here.
+
+### 7.1 The equivalent mutant, argued rather than rounded off
+
+Swapping `_release()` and `_grade()` in `submit()` is a **zero-byte** edit and
+survived the whole battery. **It is not a missing fixture and no fixture can
+close it**: `_grade()` acts only when `|standing| >= move_w` and `_release()`
+only when `|standing| < move_w`, so at most one of them can do anything on any
+read, whichever runs first.
+
+⚠️ **THE FIRST VERSION OF THE CODE CLAIMED THE ORDER WAS LOAD-BEARING**, in a
+`⚠️` comment, with a reason that sounded right. It was false, and the battery is
+what said so — **MUTATION.md habit 22 exactly, one card later: an explanation in
+a comment is a claim, and this one had not been run.** The comment now states
+the disjointness, and part 10 pins **that** — at 0, 100, 249, 250, 251 and
+1300 W — instead of pinning an order that is not observable.
+
+### 7.2 The sibling that survived, which is habit 11 earning its place
+
+`_release()`'s obligation test is `abs(standing_w) >= self.bound.move_w`.
+Swapping `move_w` for `unchanged_s` — comparing **watts against 35** — survived
+the file at **+5 B**, because **every fixture rested at exactly 0 W**, and 0 is
+below both 35 and 250. They separate only in the band between them, and a site
+can sit there: a peak-guard floor, a shadow substitution, any claim that wins
+with a small non-zero number. Closed by a three-point fixture at 0 / 100 / 300 W
+that asserts the 100 W case releases and the 300 W case does not.
+
+### 7.3 ⚠️ And the instrument lied once, which is habit 16's second half
+
+The first form of the `graded_from` mutation was
+`float(self.changed_mono or now_mono)`. It reported a **survivor at +21 B**, and
+the tree fingerprint showed the edit really was on disk and really did run.
+`changed_mono` is **0.0** in the dead-register fixture, and `0.0 or x` is `x` —
+so the mutant was a *no-op on the fixture*, for a Python truthiness reason that
+has nothing to do with the property under test. Rewritten as an explicit
+`is None` test (+82 B) it is red on four named checks.
+
+**A mutation is subject to every habit in MUTATION.md, including habit 4.** A
+purge, a fingerprint and a byte delta all say the edit is present; none of them
+says the edit *changed the answer on this stimulus*. MUTATION.md gains habit 19
+for it.
+
+---
+
+## 8. What this does NOT fix, said plainly
+
+**It does not tell a BMS refusal apart from a dead register**, and it does not
+try to. Both are re-graded on the same timer. §5.1 names what telling them apart
+would need.
+
+**It does not make the diagnosis right.** The line the operator reads still says
+*"battery-power register is not following its own command"*, which is wrong in a
+different way when the pack is simply empty. That wording is **SAFETY-56's**,
+together with `main.py`'s NOT READY row, and it is deliberately untouched here —
+two cards editing one sentence is how one of them silently loses. Only the
+**escape clause** was rewritten, because this card is what made the old one
+false, and part 10h has a named check asserting the diagnosis half is still
+there so that rewrite has to be a deliberate act.
+
+> ⚠️ **SINCE SUPERSEDED, WHICH IS WHAT THAT CHECK WAS FOR.** [[SAFETY-56]] is
+> the deliberate act: all three sentences now name **both** explanations and
+> accuse neither, and part 10h's check is inverted — it requires the accusation
+> to be **gone**. Nothing else in this section moved; the escape clause above is
+> still this card's and is untouched by it. See
+> `DECISIONS/SAFETY-56-what-the-gate-cannot-tell-apart.md`, and
+> `test_freshness.py` part 11 for the graded pair of worlds.
+
+**Survivor 5 is older than this card and is not closed by it.** After a long
+rest the unchanged clock is already past 35 s, so the **first** read carrying a
+travelled command trips the gate — before the 17.0 s in which a healthy register
+could have answered it. The live capture contains one (10:48:14, cleared one
+second later). Its size is one `stale_input_s` hold, during which `cycle()`
+returns at `inputs missing {n}s` and commands nothing differently. Fixing it
+means measuring the unchanged clock from when the **obligation** appeared rather
+than from the register's last move, which re-derives the 35.0 s bound and is a
+different card.
+
+**Nothing was measured on two inverters.** Inverter B does not physically exist
+(`goodwe/NOTES.md` §1.1b). Every two-unit figure in `test_freshness.py` is two
+copies of A's behaviour with different numbers passed in.
+
+**No deploy is proposed.** 0.10.0 is on the reference install and this branch's
+CHANGELOG row is filed under it only because `test_version_gate.py` part 11b
+requires the newest heading to be a version. Moving it, and deciding whether a
+version is cut, is a PKG card's.

goodwe_controller/DECISIONS/SAFETY-61-control-task-death.md

@@ -0,0 +1,106 @@
+# SAFETY-61 — the control task's death ends the process
+
+## 0. The defect
+
+`amain()` started `run_control()` as a bare task and waited on `stop`. Nothing
+watched the task. An uncaught exception in `read_inputs()`, `cycle()` or
+`publish()` ended the task silently, and `stop` was never set. The web UI, P1
+and tariff tasks kept running, and the Supervisor saw a healthy container. The
+traceback appeared only at shutdown. The ESP32's layer-1 veto zeroed the
+inverter about 30 s later, so the hardware was safe. The pack then sat at 0 W
+indefinitely while the add-on showed green.
+
+`test_control_task.py` reproduces this on the pre-fix tree. The child process
+reaches its 40 s deadline, has written no 0 W, and has logged nothing.
+
+## 1. Decision: exit with status 70 after the ordinary wind-down
+
+A done-callback on the control task (`control_task_done()`) handles the death.
+It logs the traceback at CRITICAL at the moment of death, then sets `stop`.
+`amain()` then runs the same wind-down that SIGTERM runs (`shutdown()` →
+`command_site_zero()`, then cancel, then clean up). After that it raises
+`ControlTaskDied`, and `main()` turns that into `SystemExit(70)` (sysexits
+EX_SOFTWARE). A normal stop and `run_control()`'s own refusal path both set
+`stop` before the task ends, so the callback ignores them. The refusal still
+exits with 78.
+
+**Why not restart the loop in the same process:**
+
+* `cycle()` writes controller state before its awaits: `cycle_at`,
+  `peak_guard`, `allocation`, then `target`/`reason`, then the writes. An
+  exception between those steps leaves the controller half-updated. A loop
+  restarted in the same process would continue from a state that no boot ever
+  produces. A process restart rebuilds the controller from the Store, which is
+  the path every boot already runs.
+* An unbounded retry is the invisible spin the card forbids. A bounded retry
+  would reimplement the Supervisor watchdog's own throttle: 10 restarts per
+  30 min, and 5 attempts with backoff (`apps/const.py`).
+
+## 2. What happens after the exit, verified rather than assumed
+
+* **Exit status reaches Docker.** The add-on image (s6-overlay, `init: false`,
+  `CMD /run.sh`) was run with `exec python3 -c 'raise SystemExit(70)'`.
+  `docker inspect` gave ExitCode 70. The same test with exit 0 gave 0, and an
+  uncaught exception gave 1.
+* **Supervisor 2026.08.0** (`ghcr.io/home-assistant/amd64-hassio-supervisor`,
+  source read from the image):
+  * A non-zero container exit is recorded as `ContainerState.FAILED`
+    (`docker/monitor.py`). The Supervisor logs *"App … exited with non-zero
+    exit code 70"* at ERROR (`apps/app.py container_state_changed`).
+  * The Supervisor restarts the add-on **only if the per-install Watchdog
+    toggle is on**. `watchdog_container()` returns when `not self.watchdog`.
+    The toggle defaults to **off** (`apps/validate.py`:
+    `vol.Optional(ATTR_WATCHDOG, default=False)`).
+  * Add-on containers get **no Docker restart policy**. The only
+    `restart_policy=` in the Supervisor belongs to the observer.
+  * `boot: auto` in `config.yaml` only controls starting at host boot. The
+    `watchdog:` key in `config.yaml` is a health-check URL, not a restart
+    policy, and this add-on does not set it.
+* **So on a default install the add-on stays stopped after this exit.** The UI
+  shows it as stopped, its log holds the traceback, and the Supervisor log holds
+  an ERROR line. The pack is at 0 W, which is the same physical state as before
+  this card. The difference is that 0 W is written immediately instead of after
+  the ~30 s veto, and the add-on no longer shows green. With the Watchdog toggle
+  on, the Supervisor restarts the add-on.
+* **Not verified:** an actual restart by a running Supervisor. That would need a
+  live Supervisor, and the only one available is the live house.
+
+## 3. Left open for the owner
+
+* Whether `DOCS.md` should tell installers to enable Watchdog. DOCS.md is not
+  this card's file.
+* Setting the Watchdog toggle from inside the add-on (`/addons/self/options`)
+  was rejected here, because it would change a user setting without the user
+  knowing.
+
+## 4. Scope: the siblings, and why they are not supervised
+
+* `run_tariff_refresh()` and the P1 HTTP and HA transports already catch
+  `Exception` inside their loops by design, and the values they feed are
+  age-bounded downstream.
+* The P1 MQTT source *returns* on purpose when it is misconfigured. Making every
+  long-lived task's end exit the process would turn that deliberate fail-safe
+  into a restart loop.
+* Only the control task is supervised.
+
+## 5. `hass.py`: an undecodable body is an absence
+
+A non-JSON `200` served as `text/html` was **already** treated as an absence,
+because aiohttp's `ContentTypeError` is a `ClientError`. The reads that actually
+escaped were these three:
+
+* a malformed body labelled `application/json`, which raises `JSONDecodeError`
+  (a `ValueError`);
+* a JSON body that is not an object, which raises `AttributeError` in
+  `number()` and `limits()`;
+* an undecodable error body in `call()`, which raises `UnicodeDecodeError`.
+
+All three were measured against aiohttp 3.13.5. The first two now read as
+`None`, and the third is now a failed write (`False`).
+
+## 6. Status row
+
+`checks()` now starts with a *control loop* row showing how long ago the loop
+last completed a pass. The row turns red once that age exceeds
+`FIRMWARE_INGEST_VETO_S`. The heartbeat is sent from this loop, so past that age
+layer 1 has zeroed the inverter.

goodwe_controller/DECISIONS/TARIFF-15-the-card-is-the-grader.md

@@ -85,11 +85,14 @@ refusal: the card's own point must land inside 0.02–1.00 EUR/kWh.
 
 ⚠️ **Its floor is applied to the ENERGY figure and not to the all-in one, and
 that asymmetry was found by a mutation rather than by reasoning.** The shipped
-`price_taxes_eur_kwh` is 0.06 — three times the floor — so a card read a
+`price_taxes_eur_kwh` was 0.06 — three times the floor — so a card read a
 hundred times too small comes out at 0.0016 EUR/kWh of energy, is carried over
 0.02 by the flat tax addend alone, and passes a band applied to the total. The
 hundredfold error is exactly what the band exists for. Graded from both
-directions in `test_price.py` 15e/15i and driven red as M10.
+directions in `test_price.py` 15e/15i and driven red as M10. *(Annotated
+2026-09-13: TARIFF-18 raised the default to 0.11736, nearly six times the
+floor. The asymmetry is unchanged in kind and larger in degree — the flat
+addend that carries a hundredfold-small card over 0.02 got bigger.)*
 
 ## 4. Fixed coefficients. No expression evaluation of any kind
 
@@ -155,4 +158,9 @@ granularity it was handed. Graded.
 * **The hour-varying network charge that bites Wallonia.** Separate card.
 * **Raising `price_taxes_eur_kwh` from 0.06 to ~0.12.** Separate card, and an
   owner's decision. Note §3b: the band's floor is deliberately insensitive to
-  whatever that number becomes.
+  whatever that number becomes. *(Annotated 2026-09-13: that card is
+  **TARIFF-18** and it shipped on this branch at **0.11736** — the Eneco
+  residential card for Flanders, September 2026, incl. 6 % VAT, summed from
+  Fluvius Antwerpen distribution 5,35 + bijzondere accijns 4,876 + bijdrage
+  groene stroom en WKK 1,51 c€/kWh. §3b held: the floor is still on the energy
+  figure and nothing in this module needed a new number.)*

goodwe_controller/DECISIONS/TEL-10-publishing-the-integrator.md

@@ -0,0 +1,182 @@
+# TEL-10 — the loop's integrator is published, as three site rows
+
+**Status:** decided and implemented on branch `TEL-10`.
+**Card:** TEL-10 — *"`self.i_w` is carried between cycles and published nowhere"*.
+**Nothing here reached the inverter, and nothing here can.** `app/control.py`
+is not touched by this branch; `compute()`, its returned `Decision` and every
+constant it reads are byte-identical to `release/1.0`. The diff is a controller
+recording three values it already had, and a publisher announcing three rows.
+
+---
+
+## 0. The three things a reader should take away
+
+1. **The row that matters is the one that is usually indistinguishable from
+   `Setpoint`.** With nothing binding, the command *is* the integrator rounded
+   to 10 W, so on a quiet day publishing the wrong one looks correct. §2 is
+   the fixture that separates them by kilowatts, and §4 is the mutation that
+   proves the separation is what the check reads.
+2. **`Loop reason` is a genuinely new sentence, not a second copy of one.** The
+   status page's `Why` row and `sensor.goodwe_controller_status` both carry the
+   *arbiter's* line (`loop -> -5000 W`), which prints the winning claim's NAME.
+   `compute()`'s own reason has never left the process, and `slew-limited` — the
+   value SAFETY-48 is about — appears in neither of the other two. §3.
+3. ⚠️ **Three entities are three entities.** This is an addition to a live
+   install's entity list, which TEL-07 refused to make for four per-unit rows
+   at a roster of one. The argument for making it here is in §5, and so is the
+   argument that keeps it to three rather than to one per inverter.
+
+---
+
+## 1. Why this is a card at all
+
+`self.i_w` has been a separate quantity from the command since SAFETY-04, which
+split the accumulator out of the velocity form precisely so the two could be
+bounded apart. Since then it has been:
+
+* carried between cycles by `Controller.cycle()`,
+* read by nothing outside `compute()`,
+* and written to no entity, no MQTT topic, no attribute and no log line.
+
+The consequence is not theoretical. The investigation behind SAFETY-48 needed to
+know what the integrator was doing during the export episodes and could only
+**reconstruct** it, from the grid trace plus a replay of the real `compute()`.
+The reconstruction reproduced about a third of the engagements it was checked
+against and was **discarded entirely** — so the card it was gathered for had to
+be argued from a measurement nobody could stand behind.
+
+⚠️ **And the reconstruction could not have been made to work.** `i_w` at a given
+instant depends on every cycle before it, including every one in which the
+arbiter overrode the loop and `main.py` re-seeded `self.i_w = self.target`. That
+re-seed is invisible in the grid trace. A replay can only recover the integrator
+on a run where the loop won every arbitration, which is not the run anybody is
+investigating.
+
+## 2. What is published, and against what
+
+Three rows, on the SITE device, appended after `release/1.0`'s eight sensors:
+
+| key | entity | what it is |
+|---|---|---|
+| `loop_i` | `sensor.goodwe_loop_integrator` | `Decision.i_w` — the accumulator AFTER this cycle, BEFORE the output clamp, the slew limit and quantisation, which is what its own docstring says it is |
+| `loop_lead` | `sensor.goodwe_loop_integrator_lead` | `decision.i_w - prev_w`, where `prev_w` is the command `compute()` was handed |
+| `loop_reason` | `sensor.goodwe_loop_reason` | `Decision.reason`, unmodified |
+
+⚠️ **`loop_lead` IS NOT A SUBTRACTION OF THE OTHER TWO ROWS, WHICH IS WHY IT IS
+A ROW.** `Setpoint` is the ARBITER's output, after every other strategy has had
+its say, and it is THIS cycle's; the lead is measured against the command the
+PREVIOUS cycle left standing. On any cycle where the arbiter overrode the loop,
+subtracting the two published rows gives a different number — and that is
+exactly the cycle on which `main.py` re-seeds the integrator, i.e. the cycle a
+reader most needs the real figure for.
+
+`cycle()` therefore records all three from the one `compute()` call, and names
+the command it passes (`loop_prev`) rather than re-reading `self.target` at
+publish time. `self.target` is reassigned later in the same method, so a lead
+computed at publish time would subtract a different cycle's command and call the
+answer a lead. ⚠️ **At the line as written the two expressions are the same
+value, and the mutation that swaps them is a recorded SURVIVOR** — see §4 M2.
+The name is kept for the coupling, not for a behaviour it currently buys.
+
+### The not-running branch
+
+`cycle()`'s `else` arm — stopped AND shadow mode off — already zeroes
+`self.i_w`, because no accumulation may survive the outage. The three rows are
+zeroed and `loop_reason` becomes `not-running` on the same branch. A row that
+kept repeating the last integrator there would say the loop was winding while
+nothing is being controlled.
+
+⚠️ **`auto: false` ALONE IS NOT THAT BRANCH.** The shipped `shadow_mode: auto`
+means a stopped controller still runs the whole decision path and records it
+(SAFETY-10), so the loop is live and the integrator is real. The first draft of
+the check asserted `not-running` about a loop that was running; it reads the
+shadow case as its own claim now.
+
+## 3. Why `loop_reason` is not the row that already exists
+
+`self.reason` is `Resolution.explain()`:
+
+```
+"loop -> -5000 W"                     # winner, watts
+"loop -> -5000 W, limited by soc"     # ...and which limit bit
+"CONTRADICTION between limits - commanding 0 W (loop)"
+```
+
+`Claim.set("loop", P_LOOP, decision.target_w, decision.reason, ...)` does carry
+the loop's reason INTO the arbiter — and `explain()` prints the winner's
+**source name**, never the claim's reason. So the loop's own word has always
+been built, handed over, and dropped one line later.
+
+Measured on the fixture in `test_telemetry.py` part 2, same cycle:
+
+```
+the arbiter's sentence: 'loop -> -5000 W'
+the loop's own word   : 'i-clamped'
+```
+
+## 4. Verified by breaking it
+
+Nine mutations, run in the CI image on a purged tree, each fingerprinted before,
+after, and again after the revert. The table with byte deltas and red counts is
+in `test_telemetry.py`'s header; two entries are worth repeating here.
+
+**M1 — `self.loop_i_w = loop_prev` (−3 B), the card's own named mutation:
+publish the COMMAND under the integrator's name.** The first draft of the
+acceptance check was *"the published integrator reaches its bound"*, and that
+check was **GREEN** under M1 — because the command reaches the bound too, twelve
+cycles later. MUTATION.md habit 4 in the check written to close the card. It
+asserts the **lead time** now (the integrator is at the bound at least ten
+cycles before the command is), and is red on 5 named checks.
+
+**M2 — `decision.i_w - self.target` (+2 B) is a SURVIVOR, and is reported as
+one.** At that line `cycle()` has not yet executed `self.target =
+resolution.target_w`, so the two expressions denote the same value and the
+mutation changes nothing that runs. The run was purged, which is not the
+direction stale bytecode fabricates. M2b (`decision.i_w - decision.target_w`,
++8 B) is the mutation that does change the value and is red.
+
+## 5. What was rejected
+
+**Publishing as an MQTT attribute on an existing entity.** There is no
+`json_attributes_topic` anywhere in this add-on; adding one would be a second
+convention for one card, and HA's recorder keeps long-term statistics for a
+state with `state_class`, not for an attribute. The reason this card exists is
+that nobody had history to read.
+
+**A status-page row instead.** The page is not recorded. `Why` already carries
+the arbiter's sentence and stays that way; DOCS.md gains the section that says
+how to read the three entities.
+
+**One integrator row per inverter.** §6.2's architecture is ONE integrator on
+the P1 meter whose output is then SPLIT. A per-unit copy would invent N of a
+thing there is one of, and the two copies would disagree the moment the
+allocator gave the units different shares. `test_mqtt.py` part 5 grades this at
+every roster length from 1 to 6, and the mutation that moves `loop_i` into
+`UNIT_SENSORS` is red on 8 named checks.
+
+**Adding the rows at N≥2 only, the way TEL-07 gates its per-unit rows.**
+TEL-07's gate exists because at a roster of one its four rows carry information
+the site rows already carry exactly. These three carry information NOTHING
+carries, at every roster length, including one.
+
+**A `## Unreleased` block in `CHANGELOG.md`.** `test_version_gate.py` part 11b
+refuses a changelog whose newest `## ` heading is not `config.yaml`'s
+`version:` — PKG-14's rule that the bump and the closed section are one act.
+Opening a section here would mean bumping the version, which is a packaging
+decision this card does not get to take. The operator-facing account is in
+DOCS.md; the release note belongs to whichever PKG ticket cuts the next
+version, and this file is what it should be written from.
+
+## 6. What this card does NOT establish
+
+* **It says nothing about whether the integrator's behaviour is right.** That is
+  SAFETY-48. This branch adds an observable and changes no decision; the
+  15.7-day replay that grades the behaviour is in that card.
+* **The three rows do not exist on the live install until the add-on is
+  updated**, and this branch does not update it. `tools/rehearsal/announced-
+  reference.txt` (what the BUILD announces) records them; `live-entities-
+  recorded.txt` (what the INSTALL has) deliberately does not, because an id the
+  build announces and the install lacks is a new entity, not an orphan.
+* **`loop_lead` is signed and is not a distance.** Where the integrator and the
+  command have opposite signs it is the sum of two magnitudes. A reader wanting
+  "how far behind is the command" should take the magnitude and say so.

goodwe_controller/DECISIONS/TEL-11-pv-production.md

@@ -0,0 +1,353 @@
+# TEL-11 — the PV production channel
+
+*What was decided, what it was decided against, and what the evidence was.*
+
+## 0. The problem, in OPT-10's numbers
+
+Over sixteen days at the reference site the pack reached 90 % SoC on **two** of
+them, and **20.5 kWh of surplus left the site while the pack still had room** —
+**12.6 kWh** of it with the battery **not charging at all**. That single
+measurement is upstream of most of what else was found that week: the nightly
+floor, SAFETY-37's misdiagnosis, the SAFETY-57 deadlock, a 2 h 47 min saturation
+freeze.
+
+It cannot be **attributed**, because **PV production is recorded nowhere in this
+system**. Three causes need three different fixes:
+
+| cause | fix |
+|---|---|
+| there was no irradiance | none — the site behaved correctly |
+| production was there, charge power was limited | a limit, somewhere |
+| production was there, the pack had room, the optimiser declined | **the only software defect** |
+
+Guessing between them is how an optimiser gets tuned to solve a cloud problem.
+**This card adds the channel and does not do the attribution.** Ship it, let it
+record a week, OPT-10 picks it up with data.
+
+## 1. It is an HA entity, not a register — and that is a product decision
+
+The RS485 bus this add-on speaks carries the **battery** inverter it drives. On
+nearly every site the PV inverter is a different box from a different vendor,
+reporting into Home Assistant through its own integration; it is **not** on this
+bus and there is no reason it would be. So the signal comes from an entity:
+`pv_entity` takes whatever `sensor.*` the site's PV integration provides, any
+brand HA can read.
+
+Reading a register would have been cheaper on one house and wrong for a fleet —
+the trade [[product-not-one-house]] names.
+
+## 2. The sign convention: **positive is production**, and there is no `pv_invert`
+
+> Reversed by TEL-14 (flag and negative caution): `DECISIONS/TEL-14-pv-sign.md`.
+
+### The convention is derived, not assumed
+
+Two sign rules already ship, and both are recorded in `DOCS.md`'s *Sources*
+table rather than inferred here:
+
+* `meter_entity` — **positive must mean importing** (`meter_invert` flips it);
+* `batt_entity` — **`+` = discharging** (`batt_invert` flips it).
+
+Both are *"positive = power arriving at the house's AC bus"*. Production arrives
+there too, so **positive = producing** is the continuation of the shipped
+convention rather than a fresh choice.
+
+### Why an invert flag would be over-building
+
+The question is not "could a sensor be reversed" — it could. It is what a flag
+would **buy**, and the answer is nothing, for two reasons that do not apply to
+the two keys it would sit beside:
+
+1. **Those two quantities are read by the control path; this one is read by
+   nothing.** `inv.batt` feeds SAFETY-30's per-unit sign check and SAFETY-31's
+   circulating-power sensor (`_read_unit()`'s own docstring says so), so a
+   reversed battery sensor hands the site a plausible number it then **acts**
+   on — a latch that trips when it should not, or does not trip when it should.
+   `pv_w` reaches no decision at all (§4), so a reversed PV sensor cannot
+   mislead one.
+2. **Production is unipolar, so the error is self-announcing.** Battery power
+   and grid power are legitimately negative half the time, which is exactly why
+   a flipped sign is invisible in them. A PV array does not consume: a reversed
+   sensor reads **−4 kW at noon**, in the first day of the very history this card
+   exists to create. An invert flag would let an installer *hide* that by
+   flipping it to something that looks right, and a second place for the sign to
+   be wrong is a second thing to get wrong.
+
+So: the convention is documented in `config.yaml`, both translations, `DOCS.md`
+and `app/pv.py`, the value is published **exactly as the sensor reports it**,
+and there is no flag. `test_pv.py` part 1 pins `-8 W` through unchanged.
+
+### And no negative-value alarm either
+
+The tempting middle path — warn when the reading is negative — needs a
+threshold, because a PV inverter's own standby draw makes a small negative
+reading at night entirely ordinary. Any threshold here would be a number nobody
+measured, in a card whose whole subject is not fabricating numbers. The
+published row is the detector.
+
+## 3. Absence is never zero, and it is not "dropped" either
+
+This is the constraint that shaped the publication, and the obvious
+implementation fails it.
+
+`MqttPublisher.publish()` **skips** a `None` value. That is right for
+`circulation` — its note in `main.py` says a missing per-unit reading should
+leave the last figure standing rather than publish a zero that reads as health —
+and it is **exactly wrong here**: a skipped row leaves Home Assistant holding
+the last number it was told, *forever*, and the recorder then draws a **flat
+line at that value through the outage**. Read back a week later that is
+indistinguishable from a real measurement, and if the last value happened to be
+small it manufactures precisely the *"there was no surplus to store"* conclusion
+the card exists to **test**.
+
+So TEL-11 publishes the absence, using Home Assistant's own mechanism:
+
+> `homeassistant/components/mqtt/const.py`: `PAYLOAD_NONE = "None"`.
+> `homeassistant/components/mqtt/sensor.py`, in the state-message handler:
+> `if payload == PAYLOAD_NONE: self._attr_native_value = None; return` — and it
+> is tested **before** the numeric branch, so it holds for a row carrying
+> `device_class: power`.
+> (github.com/home-assistant/core, branch `dev`, retrieved 2026-09-24. The
+> shipped MQTT-sensor documentation says the same thing in its `state_topic`
+> entry: *"a 'None' value will set the sensor to an unknown state"*.)
+
+The entity therefore goes to **`unknown`** and the recorder stores a **gap**.
+`mqtt.ABSENT_AS_UNKNOWN` is a one-key set and `test_pv.py` part 3 asserts both
+that the pv row gets this treatment **and that `circulation` still does not** —
+widening the rule silently would be a behaviour change to another card's row.
+
+⚠️ **What was NOT built, and why.** A per-entity `availability` block
+(`availability_mode: all`, an extra retained topic) would also produce a
+distinguishable state — `unavailable` rather than `unknown` — but it needs a
+second topic, a second retained message, a change to `_payload()`'s
+byte-order-sensitive key construction, and it survives restarts only if the
+retention is right. The payload route is one branch in `publish()` and one
+constant, and it is graded as **bytes on the topic** rather than as a claim
+about HA's availability handling.
+
+### Three states, not two
+
+| state | frame | wire | page |
+|---|---|---|---|
+| no source (`pv_entity` unset) | no `pv` key | no topic, no entity | no row |
+| no reading | `pv: None` | `goodwe_ctl/pv` = `None` | `PV —` + a caution naming the reason |
+| zero watts | `pv: 0.0` | `goodwe_ctl/pv` = `0.0` | `PV 0 W` |
+
+A failed read also **clears** the last good value (`_read_pv()` assigns on every
+call), so a reading never outlives its own sensor. `test_pv.py` part 2 drives a
+good read followed by a dead one, because a fixture that answers the same thing
+forever cannot reach that failure — MUTATION.md habit 9's shape.
+
+## 4. It must not become a control input, and that is graded twice
+
+### In the suite
+
+`test_pv.py` part 6 drives twelve cycles of the real `Controller.cycle()`
+against a 6 kW export and asserts the commands written to the inverter are
+**bit-identical** across `unset` / `no reading` / `0 W` / `8 kW` of production,
+with a precondition check that the stimulus commands something at all (habit 1).
+`inputs_ok` is asserted not to move either: a broken PV integration is **not** a
+missing input, because nothing computes with it.
+
+A computed census (habit 12 — the scope is derived from the tree, not typed)
+then reports which of the 33 modules under `app/` mention the material in any
+spelling, comments included. It is **three**: `pv.py`, `main.py`, `mqtt.py`. The
+scanner's own red direction is exercised on every run.
+
+### Across trees, by hash
+
+`tools/safety56_behaviour_trace.py` is the pattern; `tools/tel11_pv_trace.py` is
+this card's version of it, and **its control clause had to be different**, which
+is worth stating because the difference is the interesting part.
+
+SAFETY-56 changed wording and had to show behaviour did not move, so its
+`--compare` **refuses** unless the `sentences` halves **differ** — otherwise the
+two runs might be one tree twice. TEL-11's headline claim is the opposite shape:
+with the option unset, **nothing** differs. "The documents are identical" is the
+*result*, so it cannot also be the control. The two things proved instead are:
+
+* the two runs came from **different trees** (`app/*.py` sha256 + byte count,
+  compared, and an identity is **refused**);
+* **exactly one** side reacts to `pv_entity` — that side is the HEAD, the other
+  is a tree that does not have the option. Neither, or both, is refused.
+
+It drives 41 stimulus cells (5 grid worlds × 8 PV schedules, plus a run stopped
+part-way) and prints two documents per setting: `control` — every command
+written, every `self.target`, `inputs_ok`, the loop's three fields, the
+arbiter's resolution, the maintenance phase, tick by tick, **with no TEL-11
+material in it** — and `telemetry`, which is everything the card is allowed to
+move.
+
+Measured, in the CI image, on purged trees:
+
+```
+  HEAD is B; baseline is A (it does not react to `pv_entity`).
+  tree      A 73296909170ec789237d6e704cce9ab0d9f83b3df1495a14d2497285c3041a12
+  tree      B d5011b6a18e2e3803dc09cac0214b0378fa4c7388fc0ad8ad89b832a5c92af48
+  control   A unset 846a10a5b89e321086d535825925721e2f791012e8405948d4fd38d3f9d0be5f
+  control   B unset 846a10a5b89e321086d535825925721e2f791012e8405948d4fd38d3f9d0be5f
+  control   B set   846a10a5b89e321086d535825925721e2f791012e8405948d4fd38d3f9d0be5f
+  telemetry A unset a443a6ceaffe072b44bcd5f2ad946c1ed6c9e01b69e278eca631f7f4d7892164
+  telemetry B unset a443a6ceaffe072b44bcd5f2ad946c1ed6c9e01b69e278eca631f7f4d7892164
+  telemetry B set   4e6d1cb289a957223ad0205f732a6fec6110ce1f2032c98ad60694e67625274f
+OK  1/3  UNSET: control AND telemetry are byte-identical to the baseline tree.
+OK  2/3  SET: the control document is byte-identical with the channel switched on.
+OK  3/3  CONTROL OF THE CONTROL: the telemetry document DOES move when the
+         option is set (42 stimulus cells differ).
+```
+
+Note what clause 1 claims and clause 2 does not: **unset** is identical in
+`control` *and* `telemetry`, which is stronger than "the control path is
+untouched" — an install that does not set the option sees no change of any kind,
+including its announcement and its status rows. **Set** is identical in
+`control` only, which is the whole of "instrumentation, not an input".
+
+## 5. Genuinely optional — and not a second `price_now_entity`
+
+`price_now_entity` / `price_avg_entity` are legal **only** while
+`price_provider` is `off`, and the add-on **refuses to start** otherwise. That
+is the trap this card was told not to rebuild, and it is avoided structurally
+rather than by intention:
+
+* `validate.py` does not mention `pv_entity` at all. It cannot conflict with
+  anything, because nothing else reads it.
+* the MQTT row lives in `OPTIONAL_SENSORS`, not `SENSORS`, and
+  `discovery_payloads()`'s new `include` argument **defaults to empty**. So a
+  caller that has never heard of `pv_entity` — every fixture in `test_mqtt.py`,
+  `tools/rehearse_roster.py`, anything written next year — announces exactly
+  what it announced before. `p1_age` solves the same problem the other way
+  round, with `omit`, because it is announced by default and withdrawn when the
+  meter is off; getting that direction wrong here would have left most installs
+  with an entity nothing feeds, which is the hazard `omit`'s own note names.
+* the read is gated on the option, so an unset install makes **no state call at
+  all** — not a read that fails quietly.
+* there is **no status row** when it is unset. `peak_forecast_entity` nags when
+  it is unset because an unset forecast leaves a money guard without an input;
+  this is instrumentation, and a permanent caution on every install that never
+  asked for a PV channel is the warning spam the card forbids.
+* when it **is** set and the read fails, the row is `ok=False, warn=True` — a
+  **caution**. `status_payload()` builds `NOT READY` out of rows that are
+  neither `ok` nor `warn`, so a telemetry channel can never put a battery site
+  into `NOT READY`.
+
+## 6. The unit is read off the entity, and an unreadable one is refused
+
+`read_inputs()` guesses kW-or-W for `peak_forecast_entity` with
+`abs(raw) < 50`, and that is safe there: nobody's quarter-hour demand forecast
+is 50 W. It is **not** safe here — 30 W of real production at dusk is an
+ordinary reading, and that heuristic would publish it as 30 kW.
+
+So `pv.watts()` reads the entity's own `unit_of_measurement` and converts
+against Home Assistant's own `UnitOfPower` table (`mW`, `W`, `kW`, `MW`, `GW`,
+`TW`; every factor an exact power of ten). A sensor with **no** unit, or a unit
+outside that table, is **refused by name** and the status page says which. The
+refusal is loud; a guess would be silent, and a factor of 1000 in the one
+channel that exists to be believed a week later is the worse failure.
+
+⚠️ `BTU/h` is in HA's enum and is deliberately **not** in the table: its factor
+is a measured conversion rather than a decimal shift, no PV integration
+publishes in it, and a fabricated constant is what this repository's whole
+process exists to prevent. It lands in the refusal, by name, and `test_pv.py`
+part 1 pins that.
+
+## 7. The mutation battery
+
+Every check this card adds was driven by the mutation that defeats the claim it
+names. Method: `cp -a` of the tree per mutation into a **unique** directory,
+the edit applied there, `__pycache__` purged, the suites run in the CI image
+with the tree bind-mounted `:ro`, one file at a time. **The shipped tree is
+never edited**, so habit 18's revert hazard — SAFETY-37's harness killed between
+the edit and the `cp` that put the file back, and two harnesses sharing one
+backup path — is closed by construction rather than by a verified revert. Each
+row below records the byte delta, the file's sha256 before and after, and that
+the mutated line was **read back off disk** before the run started.
+
+| # | mutation | file | bytes | sha256 (first 16) before → after | red on |
+|---|---|---|---|---|---|
+| M1 | the `pv` row moved into `SENSORS`, i.e. announced on every install | `mqtt.py` | −79 B | `328d249b9d698ef6` → `532d3954c023bf3d` | 3 named in `test_mqtt.py`, 1 in `test_pv.py` |
+| M2 | `publish()` drops a `None` `pv` row again, so HA keeps the last number | `mqtt.py` | −98 B | `328d249b9d698ef6` → `dd54be458f446475` | 1 named (the acceptance criterion itself) |
+| M3 | `ABSENT_AS_UNKNOWN` widened past the one key it was written for | `mqtt.py` | +23 B | `328d249b9d698ef6` → `8fe571ebff3dacf4` | 1 named (`circulation` must still be dropped) |
+| M4 | a dead sensor reported as **0 W** instead of an absence | `pv.py` | −1 B | `55ba7471e9995436` → `9eecc34152b7ac12` | 4 named |
+| M5 | `_read_pv()` assigns only on a good read — a value outlives its sensor | `main.py` | +46 B | `c4d2cab34e50b5fd` → `189802aa69ce166d` | 2 named |
+| M6 | the unit is read and then ignored — a kW sensor published as watts | `pv.py` | −18 B | `55ba7471e9995436` → `ab19ef66c52f9379` | 2 named |
+| **M7** | **`self.grid = self.grid − self.pv_w` in `read_inputs()` — PV wired into the control path** | `main.py` | +106 B | `c4d2cab34e50b5fd` → `c38216edb7c5c8db` | **2 named, plus `tel11_pv_trace.py` clause 2/3 on 26 of the 41 stimulus cells** |
+| M8 | `optional_keys()` returns `("pv",)` unconditionally | `mqtt.py` | −52 B | `328d249b9d698ef6` → `86ff23efe3088ad8` | 3 named |
+| M9 | the PV caution made a `bad` row, i.e. a dead sensor is a `NOT READY` | `main.py` | +1 B | `c4d2cab34e50b5fd` → `45c74cab89943564` | 1 named |
+| M10 | the read gate removed — an unset option is read once a second forever | `main.py` | −10 B | `c4d2cab34e50b5fd` → `b67baa8aba3019e8` | 2 named, **plus two crashes** |
+
+`on_disk = True` for all ten: the mutated line was grepped back out of the file
+after the edit and before the run (MUTATION.md reporting rule 2), and no
+mutation is size-preserving, so rule 1's `+0 B` caveat does not arise.
+
+⚠️ **M10's two extra reds are CRASHES, not named checks, and that is recorded
+rather than tidied away.** Every `Hass` double in `test_inverter.py` and
+`test_telemetry.py` predates this read and has no `state()` method, so an
+unconditional PV read is an `AttributeError` rather than a failed assertion —
+habit 20's shape, a red with no name attached. Fixing those fixtures would be a
+change to what *their* checks report and belongs to whoever next touches them;
+this card's own fixture has `state()` and grades the property by name.
+
+⚠️ **M7's trace limb is where the two halves meet.** The mutant moves the
+control document on 26 of 41 cells — every cell whose PV schedule produces a
+READING. The five `none` cells and the five `zero` cells do **not** move, which
+is correct and is worth seeing: subtracting nothing, and subtracting zero,
+change nothing. A battery that only drove a dead sensor would have reported this
+mutation as a survivor for the third time.
+
+The clean tree those `before` hashes belong to: `app/main.py`
+`c4d2cab34e50b5fd`, `app/mqtt.py` `328d249b9d698ef6`, `app/pv.py`
+`55ba7471e9995436`.
+
+### ⚠️ M7 was a SURVIVOR on the first battery, and the fixture was the reason
+
+The card's **central** mutation — `self.grid = self.grid - self.pv_w` in
+`read_inputs()`, i.e. exactly the defect the whole card forbids — came back
+**green** on a six-file run at **+106 B**, on disk, purged, genuinely running.
+
+The property did not hold; the fixture could not reach it. `test_pv.py` part 6
+drove a **6 kW export over 12 cycles**, which puts the loop **against its
+rail**: the command moves `slew_w` every cycle and −6000 W and −14 000 W of
+apparent error produce the **same ramp, tick for tick**. MUTATION.md habit 23,
+with a saturated actuator in place of a coinciding value — and the habit's list
+of no-op-prone constructs is all *expressions*, so this is worth its own entry,
+which it now has.
+
+The fixture now drives a **600 W import the loop settles on**, with a
+responsive meter (`grid = base − batt`) so the error actually closes, asserts
+the resting target is well inside the rail, and asks habit 23's own question as
+its own check: **shift the meter by the same 8 kW and confirm the commands
+really would have moved.** On the first fixture that question answers *no*, in
+one line. Every number in the table above is from the battery re-run against
+the fixed tree.
+
+⚠️ **A red count is a property of the suite as much as of the mutation.** These
+name **this** tree at this commit; a later card that adds or re-bases a check
+moves the number with the mutation untouched. Re-measure rather than inherit.
+
+## 8. What none of this covers, with shapes
+
+* **Home Assistant itself.** That `None` renders as `unknown` and that the
+  recorder keeps a gap is read out of HA's source and quoted in §3; no HA runs
+  in this suite. What is graded here is the bytes this add-on publishes.
+* **Whether the operator's sensor tells the truth.** A sensor wired backwards,
+  or reporting DC where AC was meant, or a string instead of the array, is
+  published faithfully. §2 is the argument for why that is the right failure
+  mode; it is not a claim that it cannot happen.
+* **A roster of more than one.** The row is a **site** row — there is one PV
+  array as far as this add-on is concerned — so nothing per-unit exists to
+  separate, and every fixture is the shipped roster of one.
+* **The attribution.** This card records production. Whether the 20.5 kWh was
+  cloud, a limit or the optimiser is OPT-10's, and it needs a week of this
+  channel's history before it can be asked.
+* **`tools/`, the firmware and the ingress HTML** are outside part 6's census.
+* **The identity is only as wide as the stimulus.** `tel11_pv_trace.py` prints
+  its 41 cells with the documents for exactly that reason.
+
+## 9. No `CHANGELOG.md` entry
+
+`test_version_gate.py` 11b refuses a newest `## ` heading that is not
+`config.yaml`'s `version:`, and opening an `## Unreleased` section would mean
+taking a packaging decision this card does not get to take. The operator account
+is in `DOCS.md`; the release note belongs to the next PKG ticket, which should
+say that **0.10.1 → next** adds one optional key, announces no new entity on an
+install that does not set it, and changes no control behaviour.

goodwe_controller/DECISIONS/TEL-12-several-pv-inverters.md

@@ -0,0 +1,361 @@
+# TEL-12 — several PV inverters, and why a partial total is worse than none
+
+TEL-11 shipped `pv_entity` as a single `str?` in 0.11.0. The owner of the
+reference site reported **within minutes of it going live** that they have
+several PV inverters and could configure one.
+
+That is not a property of one house. A multi-string or multi-orientation roof
+routinely carries two or three inverters, each publishing its own power sensor
+into Home Assistant, and the add-on is sold to clients. So the channel had to
+become a roster.
+
+**OPT-10 is blocked on this and cannot start recording until it lands.** Which
+sets the bar: the number this channel publishes has to be one an attribution can
+believe, or the week of history OPT-10 is waiting for is worse than no history.
+
+---
+
+## 1. The surface: `pv_entities` beside `pv_entity`, and the measurement that
+decided it
+
+Two candidates, and they differ on exactly one question nobody in this
+repository could answer by reading: **does Supervisor accept a stored STRING for
+a key whose schema has become a LIST?** 0.11.0 shipped `pv_entity: str?`; the
+live install *has* a string persisted in it; and an upgrade that refuses that
+string leaves an add-on which will not start — CFG-04 §B's trap, in the other
+direction, with the schema needed to fix it pinned to the version that cannot be
+installed.
+
+It was measured, against the release image, by a new **§G** of
+`tools/supervisor_shape_probe.py` — the instrument CFG-04 built for exactly this
+kind of question:
+
+```
+docker run --rm -v "$PWD:/w:ro" -v "$PWD/tools:/probe:ro" --entrypoint python3 \
+  ghcr.io/home-assistant/amd64-hassio-supervisor:2026.08.0 \
+  /probe/supervisor_shape_probe.py
+```
+
+```
+== G. TEL-12: the SHAPE of a several-inverter PV option ==
+  PASS  the shipped defaults with a 0.11.0 `pv_entity` STRING on top are ACCEPTED - the baseline every refusal below is varied from
+        pv_entity='sensor.pv_power' pv_entities=[]
+  PASS  ⭐ THE MEASUREMENT THAT DECIDED THE SURFACE: with `pv_entity` declared as a LIST, the string an 0.11.0 install has persisted is REFUSED, and the refusal names the key - so that shape would leave the live add-on unable to start on upgrade
+        Invalid list for option 'pv_entity' in GoodWe RS485 Controller (local_goodwe_controller)
+  PASS  ...and a shipped `pv_entity: []` DEFAULT does not rescue it: deepmerge's list strategy is `override`, so the operator's string survives the merge and is refused anyway
+        Invalid list for option 'pv_entity' in GoodWe RS485 Controller (local_goodwe_controller)
+  PASS  ...(the list shape itself is fine - it is only the STORED STRING it refuses, which is what makes this a migration and not a schema question)
+        a list value validates
+  PASS  ⚠️ ONE SPELLING DOES ACCEPT BOTH - `match(.*)?` - AND IT IS REJECTED FOR A DIFFERENT REASON, MEASURED HERE: it validates NOTHING. A string passes, a list passes, and so does the integer 417; and the Configuration tab renders it as a plain text box rather than a repeatable field, so an operator cannot enter a second inverter in the UI at all
+        string=True list=True integer-417=True ui=[{"name": "pv_entity", "optional": true, "type": "string"}]
+  PASS  ⭐ THE SHIPPED SHAPE: an 0.11.0 blob - `pv_entity` a string, no `pv_entities` key at all, because it did not exist when that blob was written - validates against THIS manifest, with the new key defaulted to the empty list. The live install upgrades without touching its options
+  PASS  ...and a three-entity roster validates, per-entry, with both keys set - which the add-on resolves by REPLACEMENT and says so on its status page
+        ["sensor.pv_east", "sensor.pv_west", "sensor.pv_garage"]
+  PASS  ⭐ ...and the shipped `options:` block with ONLY `pv_entities` removed is REFUSED, BY NAME - `Missing option 'pv_entities' in root`. That is why the `pv_entities: []` default is load-bearing, exactly as `inverters: []` is: Supervisor treats a nested list as required unless its element is an OPTIONAL scalar, and `- str` is not one
+        Missing option 'pv_entities' in root in GoodWe RS485 Controller (local_goodwe_controller)
+  PASS  ...and the Configuration tab renders it as a REPEATABLE string field (`multiple: true`), so an operator adds their second and third inverter in the UI rather than in YAML
+        [{"name": "pv_entity", "optional": true, "type": "string"}, {"name": "pv_entities", "multiple": true, "required": true, "type": "string"}]
+  PASS  a DOWNGRADE to a schema without `pv_entities` drops the key with a warning rather than refusing, and leaves `pv_entity` standing - so rolling back to 0.11.0 returns the install to its single entity rather than bricking it
+
+== all cases passed ==
+```
+
+| Claim | Evidence |
+|---|---|
+| **Option 1 — `pv_entity` becomes a list — cannot ship** | §G: `Invalid list for option 'pv_entity'` on the string an 0.11.0 install has stored |
+| …and a `[]` default does not rescue it | §G: `_OPTIONS_MERGER`'s list strategy is `override`, so the operator's string survives the merge and is refused anyway |
+| …and it is not a *schema* problem | §G: a list **value** validates fine against a list schema. It is a **migration**, and a migration is a bigger ticket than this |
+| **One key CAN carry both shapes** — `match(.*)?` | §G, and reported even though it *passes*, because "no spelling accepts both" would have been a **false reason** to reject option 1 |
+| …and it loses anyway, for a measured reason | §G: it validates nothing at all — a string, a list, and the integer `417` all pass — and the Configuration tab renders it as a plain text box, so an operator cannot add a second inverter in the UI |
+| **Option 2 — `pv_entities` beside `pv_entity` — ships** | §G: the 0.11.0 blob validates untouched, the new key defaults to `[]`, three entities validate, the UI renders `multiple: true` |
+| `pv_entities: []` in `options:` is load-bearing | §G: the shipped defaults **minus only that key** are refused with `Missing option 'pv_entities' in root` — CFG-04 §B's isolated counterfactual, for this key |
+| A downgrade is not the trap in reverse | §G: a schema without the key **drops** it and leaves `pv_entity` standing |
+
+`p1_phase_import_entities` (`options: []` + `schema: - str`) is the shipped
+precedent for the pair; nothing new was invented.
+
+**So the surface is uglier than option 1 and that is the correct trade.** The
+cleanest surface that breaks the one install this card exists to fix is not the
+cleanest surface.
+
+### And `pv_entities` REPLACES `pv_entity` rather than extending it
+
+CFG-04's rule for `inverters:` ("declared, it REPLACES those six keys"), applied
+to the only upgrade path that matters. The install being upgraded **has**
+`pv_entity` set, to inverter A. Opening the Configuration tab, the natural action
+is to put *all* the inverters in the new repeatable field — and under a union
+rule that **double-counts A** unless the operator also remembers to clear the old
+key. A doubled total is the same defect as a partial one pointing the other way,
+in the one channel that exists to be believed a week later.
+
+Under replacement the effective roster is exactly what one key says, and no
+arithmetic depends on a de-duplication rule the operator has to know about. It
+de-duplicates *within* the list (a site cannot have two sensors with one
+entity_id, so a repeated id is a typo that would double that inverter), and
+`Controller.checks()` prints a **caution** whenever both keys are set saying
+which one won — a replacement nobody is told about is the "one of which silently
+wins" `config.yaml` refuses elsewhere.
+
+⚠️ It is a **caution and never a refusal to start**. `validate.py` still does not
+mention either key. A telemetry channel that could stop a battery site from
+starting would be observability with a foot in the control path.
+
+---
+
+## 2. ⚠️⚠️ The decision the card turns on: absence of ONE is absence of the TOTAL
+
+Three inverters configured, one `unavailable`. The sum of the other two is **a
+smaller number indistinguishable from a real one.** Fed into OPT-10's
+attribution it reads as *"there was less PV than there was"* — which is the "no
+irradiance" conclusion the channel exists to **test** rather than to manufacture.
+
+Two designs were genuinely available:
+
+**(a) publish the total as absent** — `pv.total()` answers `None`, the topic
+carries HA's own `None`, the entity goes to `unknown`, the recorder stores a gap.
+
+**(b) publish the partial sum alongside a count of how many contributed.**
+
+**(a) shipped.** It wins on the one question that matters, which is *who reads
+the number and when*:
+
+* The **MQTT row** is read back **cold**, a week later, by OPT-10 and by anything
+  that plots `sensor.goodwe_pv_power` over that week. A partial sum there is a
+  smaller number indistinguishable from a real one, and the count that would
+  have qualified it lives in a **second entity with its own history** — so
+  believing the total requires joining two recorder series by timestamp to find
+  out which samples to distrust. Nobody re-derives that. And it is worse than a
+  gap in exactly the direction that matters: **a gap makes the attribution say
+  "I do not know"; a partial makes it say something false.**
+* The **status page** is read **live**, by a human who wants the diagnostic. So
+  the partial information is *not* thrown away — the row names every entity that
+  did report, with its watts, and every one that did not, with its reason, and
+  states plainly that there is no site total. Different reader, different
+  instant, different rule.
+
+A count published beside the total would also carry **no information** in the
+state (a) admits: the total is published *only* when every entity contributed, so
+the count would be the constant `len(roster)`.
+
+And this **extends** TEL-11's rule rather than weakening it. `mqtt.py`'s
+`ABSENT_AS_UNKNOWN` is still exactly one key and `publish()`'s `None` handling is
+untouched: the line that turns an absence into HA's `unknown` did not have to
+change, because "absence is never zero" already covered this one layer up.
+
+### The mirror, which matters just as much
+
+A member honestly reporting **0 W** is **summed**, not treated as absent. The
+test is `watts is None`, never falsiness. Shading, a tripped string and
+nightfall are all real zeros, and a roster that blanked the site whenever one
+member read zero would report an absence **on every clear evening** and defeat
+the channel from the other end.
+
+### ⚠️ And the answer is NOT "document a template sensor that adds them up"
+
+An operator may legitimately prefer one, and `pv_entity` will happily point at
+it. Shipping it as *the* answer pushes the absence problem onto them unseen: a
+template sensor summing an `unavailable` source silently yields the partial
+total — the same defect one layer down, in a place this add-on cannot see or
+report. DOCS.md says so in those terms.
+
+### The three published states, side by side
+
+| what happened | frame | `goodwe_ctl/pv` | status page |
+|---|---|---|---|
+| no roster at all | no `pv` key | no topic, no entity | no row |
+| 1200 / 2100 / 450 W, all three | `pv: 3750.0` | `3750.0` | `PV  3 750 W` + one ok row naming all three |
+| all three answer, one of them `0 W` | `pv: 1650.0` | `1650.0` | `PV  1 650 W` |
+| one of the three `unavailable` | `pv: None` | `None` → `unknown`, recorder **gap** | `PV  —` + a caution naming the missing entity, its reason, and what the others reported |
+| all three gone | `pv: None` | as above | as above |
+
+---
+
+## 3. Still not a control input
+
+Unchanged, and re-proved at the new roster size.
+`tools/tel11_pv_trace.py` was **extended rather than replaced** — the file name
+still says TEL-11 because `DECISIONS/TEL-11-pv-production.md` §5 and
+`test_pv.py`'s mutation table quote it, and a renamed instrument makes both
+references dangle for no gain.
+
+It now produces **three** document sets per tree — `unset`, `one`, `multi` — and
+grades five claims. The roster cells live in their own document precisely so
+`unset` and `one` keep the `control` hashes TEL-11 recorded; appending cells to
+an existing document would have moved a hash whose stability is itself the
+evidence.
+
+```
+$ python3 tools/tel11_pv_trace.py --compare base.json head.json
+  HEAD is B; baseline is A - its roster cells ARE its unset cells, which is what a tree that has never heard of `pv_entities` does with them.
+  supports_roster   A False / B True   (self-reported; the verdict above is MEASURED)
+  tree      A fa92ba6a6fc6d49c0f87a494e03b530a8575212a0b2c3046629cb400ef2ae0d4
+  tree      B 0b39198015b6a5a3f7538d4157d77ecadc89311daef18fce883762d94d8351eb
+  control   A unset 846a10a5b89e321086d535825925721e2f791012e8405948d4fd38d3f9d0be5f
+  control   B unset 846a10a5b89e321086d535825925721e2f791012e8405948d4fd38d3f9d0be5f
+  control   A one   846a10a5b89e321086d535825925721e2f791012e8405948d4fd38d3f9d0be5f
+  control   B one   846a10a5b89e321086d535825925721e2f791012e8405948d4fd38d3f9d0be5f
+  control   A multi 2aafbfedfb9cc939082b36eeb7493289808fb21cd41113322d4817de0e414a30
+  control   B multi 2aafbfedfb9cc939082b36eeb7493289808fb21cd41113322d4817de0e414a30
+  telemetry A unset a443a6ceaffe072b44bcd5f2ad946c1ed6c9e01b69e278eca631f7f4d7892164
+  telemetry B unset a443a6ceaffe072b44bcd5f2ad946c1ed6c9e01b69e278eca631f7f4d7892164
+  telemetry A one   4e6d1cb289a957223ad0205f732a6fec6110ce1f2032c98ad60694e67625274f
+  telemetry B one   4e6d1cb289a957223ad0205f732a6fec6110ce1f2032c98ad60694e67625274f
+  telemetry A multi d269168ffece375027c2c18ea33631a961ff92775781884a0592d6a37d78845c
+  telemetry B multi 550a49a73f39267ba28b1e78cd12b8f5c71ef7269bbbd2e12112696be0fef1ff
+OK  1/5  UNSET: control AND telemetry are byte-identical to the baseline tree. …
+OK  2/5  ONE ENTITY: control AND telemetry are byte-identical to 0.11.0's single-entity path - the same commands, the same payloads, the same status rows, the same announcement.
+OK  3/5  CONTROL, ONE ENTITY: the control document is byte-identical with the channel switched on - PV reaches no decision.
+OK  4/5  CONTROL, THREE ENTITIES: every roster cell's control document equals its grid world's `unset` one - 30 cells over 5 grid worlds, covering three healthy entities, one dead at EVERY position, all three dead and one honestly reporting 0 W. Neither the total nor any PARTIAL total reaches a decision, and the document is byte-identical to the BASELINE tree's for the same cells.
+OK  5/5  CONTROL OF THE CONTROL: the telemetry document DOES move under a roster (30 stimulus cells differ from their grid world's unset telemetry), so 1/5-4/5 are identities this instrument could have broken. AND in no cell with a dead member does the PV row carry the partial sum of the survivors, while every cell whose members all ANSWER publishes its total - including the one where a member honestly reports 0 W.
+$ echo $?
+0
+```
+
+**The control hash is unmoved: `846a10a5b89e…` on `unset` and on `one`, on both
+trees.** The roster control document `2aafbfedfb9c…` is byte-identical between
+the two trees, which is the strongest available form of the claim — the baseline
+runs those cells with a key it has never heard of, so its control document for
+them *is* 0.11.0's.
+
+⚠️ **2/5 is a claim TEL-11 could not make.** TEL-11's baseline had no channel at
+all to be identical to; TEL-12's baseline is 0.11.0, so "one entity behaves
+exactly as 0.11.0 does" is a real cross-tree identity over **both** documents.
+`pv.total()` passes a single entity's `(watts, why)` through verbatim for exactly
+this reason, and `Controller.checks()` keeps 0.11.0's two f-strings in a
+`len(...) == 1` branch rather than generalising them.
+
+### ⚠️ TEL-11's `--compare` refusal had to change, and that is a finding
+
+TEL-11's rule was *"exactly ONE side's `set` document may differ from its own
+`unset` — that side is the HEAD"*. It was correct evidence when written, because
+`release/1.0` predated `pv_entity` entirely. `release/1.0` is 0.11.0 now, **both**
+sides react to `pv_entity`, and that refusal fires on **every honest run**. The
+discriminator is the roster instead: only the HEAD has heard of `pv_entities`, so
+only the HEAD's `multi` document fails to reduce to its own `unset` one.
+
+It is asserted from the **documents**, not from `tree.supports_roster` — a
+self-report is the tree describing itself, whereas "this side's behaviour did not
+move when `pv_entities` was set" is the tree being measured. `supports_roster` is
+printed beside the verdict so a disagreement between the two is visible.
+
+See MUTATION.md habit 24.
+
+---
+
+## 4. Mutation battery
+
+Twelve mutations, each on a **fresh `cp -a`** of the clean worktree (never
+reverted — habit 18 / TARIFF-09's method), `__pycache__` purged before the run
+and the tree checked for one afterwards, byte delta from `stat` and the edit
+confirmed on disk with `cmp`, suites run in the CI image with `checks.yml`'s own
+command one file at a time under a `:ro` mount.
+
+| mutation | bytes | reds |
+|---|---|---|
+| N1 `total()` returns the partial sum, not an absence | +42 B | 6 named in `test_pv.py` + 1 crash |
+| **N1b ⭐ THE REJECTED DESIGN: the partial sum with a contributor count** | −282 B | **10 named + the trace `REFUSED 5/5`** |
+| N2 absence tested by falsiness (`not w`) | −4 B | 2 named |
+| N3 `pv_entities` UNIONS with `pv_entity` | −27 B | 3 named |
+| N4 the de-duplication dropped | −15 B | 1 named |
+| N5 `sum` → `max` over the roster | **+0 B** | 6 named |
+| N6 the roster-of-one stops passing `why` through | +13 B | 8 named |
+| N7 `optional_keys()` back to reading `pv_entity` | −6 B | 1 named + 1 crash |
+| N8 `self.grid -= self.pv_w` in `read_inputs()` | +106 B | 3 named + the trace (52 cells on 2/5, 26 on 3/5, 10 on 4/5) |
+| N9 the roster caution made a `bad` row (NOT READY) | +1 B | 1 named |
+| N10 `entity_is_ignored()` always False | +10 B | 2 named |
+| N11 `pv_entities: []` deleted from `options:` | −18 B | 2 named in `test_translations.py` + `11 CASE(S) FAILED` in the probe |
+
+**No survivors.**
+
+⚠️ **N5 is `+0 B` — the risky delta.** `sum` and `max` are the same three
+characters, so neither the file size nor its mtime moved, and TEST-15's
+stale-bytecode defect is exactly what manufactures a survivor there. The run was
+on a fresh purged copy and `cmp` confirmed the edit on disk before it started.
+
+⚠️ **N1b is the row that matters, and it is not a defect.** It is the *other*
+defensible design, implemented and run. The point is that the checks and the
+instrument can **tell the two apart** — an unexamined partial sum is what the
+card forbids, so a check that could not see one would be decoration:
+
+```
+REFUSED 5/5: THE PARTIAL SUM IS ON THE WIRE at [('EXPORT-6K/EAST-DEAD', '2550.0'),
+('EXPORT-6K/GARAGE-DEAD', '3300.0'), ('EXPORT-6K/WEST-DEAD', '1650.0'),
+('IMPORT-3K/EAST-DEAD', '2550.0'), ('IMPORT-3K/GARAGE-DEAD', '3300.0'),
+('IMPORT-3K/WEST-DEAD', '1650.0')] … - a smaller number indistinguishable from a
+real one, which is the defect this card exists to prevent.
+```
+
+⚠️ **N8's 1/5 stays GREEN and that is correct rather than a miss.** With no PV
+entity configured `pv_w` is `None` and the leak cannot fire — which is what makes
+1/5 a claim about the **default** and 2/5–4/5 the claims about the channel.
+
+### The fixture values are the design (habit 10 and habit 23)
+
+`test_pv.py` carries **two** rosters over the same three entities, because the
+two claims need different magnitudes and one fixture cannot serve both.
+
+* **Parts 8–10: 1200 W + 2.1 kW + 450 W = 3750 W.** The sum is separable from
+  max (2100), min (450), first (1200), last (450), mean (1250), count (3) and
+  every partial of itself (2550 / 1650 / 3300) — the family is computed, printed
+  and asserted non-colliding as its own precondition. One member is in **kW** so
+  "correct against their own units" is exercised. **Not one member is zero**: a
+  member contributing 0 W could go absent without moving the sum of the rest, and
+  a fixture like that cannot tell "published the absence" from "published the
+  partial sum" — habit 23 with a coinciding value in the *fixture* rather than in
+  the plant, which is precisely the trap the brief named. Absence is driven at
+  **every position** of the roster, not at one (habit 10's fixture-as-a-SET), and
+  each position's partial is **derived from the fixture** rather than typed
+  beside it.
+* **Part 6: 1500 W + 4.5 kW + 2000 W = 8000 W.** Sized so every *partial*
+  (6500 / 3500 / 6000) would still **move** a loop settling on a 600 W import.
+  Habit 23's own question is asked twice — shift the meter by 8000 W, and again
+  by 3500 W, the smallest partial any single dead member could produce — because
+  a leak of the partial is a different mutation leaking a smaller number.
+
+### Two false results this card produced, and what they were
+
+Both were in the **instrument**, and both are recorded rather than tidied away.
+
+1. `partial_w`/`partial_wire` were first written **inside** each telemetry cell.
+   They are a fact about the *stimulus*, produced by the tool and identical on
+   both trees — so every roster cell differed from its unset reference for a
+   reason that was not behaviour, and the HEAD/baseline discriminator fired on
+   *both* sides. They live in a separate top-level `partials` map now.
+2. The `WEST-ZERO` cell (all three answer, one honestly reporting 0 W) had its
+   **true total** labelled as its "partial". 5/5 then refused the *shipped* tree
+   for publishing 1650 W, which it is required to publish. A cell with no dead
+   member has no partial to leak, and `never` is `None` there.
+
+---
+
+## 5. What none of this can see
+
+* **Home Assistant itself.** That `None` on the state topic renders as state
+  `unknown` and that the recorder keeps a gap is read out of HA's source and
+  quoted in `app/mqtt.py`; whether the long-term statistics table then
+  interpolates across the gap is HA's behaviour, and OPT-10 will be reading it.
+* **Whether the operator's sensors are telling the truth.** A sensor wired
+  backwards reads −4 kW at noon and is summed as −4 kW. There is deliberately no
+  `pv_invert` — §2 of the TEL-11 record is the argument, and it holds at a roster.
+* **A roster larger than three.** Three is the smallest size at which the sum
+  separates from the reduction family *and* absence can be driven at every
+  position. Nothing here says what twenty entities do to a cycle's latency — the
+  read is `asyncio.gather`ed across the roster for exactly that reason, so a slow
+  sensor costs what one costs, but that is an argument rather than a measurement.
+* **A PV roster combined with a two-inverter battery roster.** No fixture
+  crosses CFG-04's `inverters:` with `pv_entities`.
+* **The real MQTT transport, and wall-clock behaviour.** As TEL-11.
+
+---
+
+## 6. Not deployable as merged
+
+`config.yaml` stays at `0.11.0`, so `tools/predeploy_check.py` reports a NO-OP
+until PKG cuts a version. A CHANGELOG entry is **wanted** and was deliberately
+not written: `test_version_gate.py` 11b forbids an `## Unreleased` heading and
+the bump is PKG's call. The material an entry needs is this file.
+
+The option surface moves **76 keys → 77**, one new optional key, `pv_entities`,
+empty on every install that does not set it.
+
+**Superseded in part (UX-08, 2026-09-27):** the PV status rows no longer read 0.11.0's sentences at one entity. The owner ruled out entity ids on status rows, so 2/5 now holds for the control document only. See `UX-08-short-notifications.md`, phase 2b item 3.

goodwe_controller/DECISIONS/TEL-14-pv-sign.md

@@ -0,0 +1,83 @@
+# TEL-14 — the PV sign, declared per entity
+
+Owner report on 0.12.0: `sensor.espressif_vermogen` (ESPHome clamp) and
+`sensor.kwh_meter_actueel_vermogen` (kWh meter in the PV circuit) read
+**positive for consumption, negative for production**. At night the page said
+"✓ PV production: 13 W" — standby draw. By day production would publish negative.
+
+## 1. This reverses TEL-11 §2, and why
+
+TEL-11 §2 refused a `pv_invert` on two grounds. "PV is read by nothing in the
+control path" still holds: the flip lives in `pv.total()`, and `test_pv.py`
+part 12 re-runs part 6's 40-cycle identity with a flip set. "A reversed sensor
+announces itself" did not survive a real site: these sensors follow a different
+convention, read a plausible small positive number at night, and the only other
+fix is a template sensor, the place TEL-12 §2 says goes quietly wrong.
+
+## 2. The shape: a parallel list, `pv_invert_entities`
+
+Measured by `tools/supervisor_shape_probe.py` §H (Supervisor 2026.08.0, against
+a 0.12.0 blob); re-run it for the transcript.
+
+| shape | schema | why it lost / won |
+|---|---|---|
+| (a) `-sensor.x` prefix | accepted | invisible: the sign is a syntax only the description explains, in a field an installer fills with the entity picker's text |
+| (b) parallel list | accepted, 0.12.0 blob unchanged | **ships**: its own labelled, translated field ("PV entities whose sign is reversed"); an installer lists the odd ones out |
+| (c) dicts on `pv_entities` | **refuses 0.12.0's stored strings** | bricks the upgrade — TEL-12's trap again |
+| (c2) dicts as a third key | accepted | per-entry labels render raw (`entity`, `invert`) — probe §F; and a third PV surface |
+| (d) global bool | accepted | one sign cannot describe inverter + meter in one roster |
+
+(b)'s known cost is a typo in the second list: `pv.stray_inverts()` turns it into
+a named caution. `[]` in `options:` is load-bearing (§H, isolated counterfactual).
+Default `[]` flips nothing, so every 0.12.0 install is byte-identical (part 12).
+
+## 3. The negative caution: per entity, below −50 W
+
+The owner's two meters draw ~13 W at night, so a *correctly* signed meter reads
+about −13 W then. −50 W clears that with room for a few such devices behind one
+entity; a reversed sensor by day reads hundreds to thousands of watts below
+zero. It is tested **per entity, not on the total** (a deviation from the brief):
+three correct meters at −20 W sum to −60 W and must stay quiet, while a reversed
+−1500 W hidden inside a positive total must not. It is a caution, never `bad`;
+a wrong threshold costs a spurious or missed caution, never data. The text says
+ADD (unflipped) or REMOVE (already flipped).
+
+## 4. Mutations
+
+Fresh `cp -a` each, `__pycache__` purged, CI image, `:ro`, `--network none`;
+`test_pv.py` only unless stated. T1-T12 at 7559d21; M2/M5 are review #1628's,
+red since B1 (merged into release/1.0 @ 43b2740).
+
+| # | mutation | bytes | reds |
+|---|---|---|---|
+| T1 | flip ignored in `total()` | −45 | 9 |
+| T2 | flip applied to every member | −7 | 6 |
+| T3 | `0.0 - w` → `-w` | −5 | 1 |
+| T4 | flip written as `abs()` | −1 | 2 |
+| T5 | `_read_pv()` stops passing the flip | −26 | 7 |
+| T6 | caution threshold −50 → 0 W | −17 | 3 |
+| T7 | `[sign inverted]` marker dropped | −39 | 3 |
+| T8 | negative caution made `bad` | +1 | 1 |
+| T9 | `stray_inverts()` always empty | −50 | 1 |
+| T10 | `inverted()` stops stripping | −8 | 1 |
+| T11 | ADD/REMOVE advice swapped | +4 | 2 |
+| T12 | `pv_invert_entities: []` deleted from `options:` | −25 | 2 test_translations + 17 probe |
+| M2 | `stray_inverts()` roster ignores `pv_entity` | +15 | 2 (REPORTED CASE, PADDING) |
+| M5 | `_read_pv()` flip set not stripped | +25 | 1 (PADDING) |
+
+## 5. History
+
+OPT-10's `sensor.goodwe_pv_power` recorded since 2026-09-24 on an install with
+such sensors carries the old sign; nothing rewrites it.
+
+## 6. CHANGELOG entry for the next PKG cut
+
+Not written into `CHANGELOG.md`: `test_version_gate.py` 11b/11d refuse an
+`## Unreleased` heading (measured on this branch: 4 reds). For PKG to paste:
+
+> **`pv_invert_entities` (TEL-14).** A PV sensor that reads negative while
+> producing — typically a kWh meter or power clamp in the PV circuit — can now
+> be listed under *PV entities whose sign is reversed* in the Configuration tab;
+> its sign is flipped before the sum and the status page marks it. Empty (the
+> default) changes nothing. ⚠️ PV history recorded before you set it keeps the
+> old sign.

goodwe_controller/DECISIONS/UX-08-short-notifications.md

@@ -0,0 +1,63 @@
+# UX-08 phase 2a: short notifications, and what moved out of them
+
+The owner decided on 2026-09-27: a title of at most about 5 everyday words and a one-sentence body. A red safety alarm may use up to 3 sentences, so no action-relevant information is lost. Titles are neutral, with no "GoodWe:" prefix. HA entity ids appear only in refusals. The rule is `STYLE.md` at the repository root, the texts are in `app/messages.py`, and `test_messages.py` enforces both. The detail each notification used to carry is in DOCS.md under "Notifications", and the body links to it.
+
+**Unchanged:** every `notification_id`, every trigger and cadence (edges, SAFETY-34 re-announce, per-unit ids), every log line and every status row. The status banner and rows are phase 2b, refusals and option texts 2c, logs 2d; `ux08_allowlist.txt` lists them until then.
+
+## Where a choice was made
+1. **Severity of "not delivering" (SAFETY-42).** The notification is an *alarm*, so it may use 3 sentences. Its log line is ERROR and the alarm is latched. The page banner stays amber, as SAFETY-42 decided, because control keeps running; the two answer different questions (is control running / must a person act) and HA shows no colour on a notification. The three checks stay in their original order. Clearing it takes stop then start, and the body says so.
+2. **Figures left the bodies** of the frozen-meter card (the rail and the command), the circulating-power card (the watts and the time window) and the peak cards (the projection). None of them is needed to act, and all of them are still in the reason text that the log line and the status row carry. `test_freeze.py` and `test_watchdog.py` now pin that. The frozen-meter card can therefore no longer quote a wrong rail (SAFETY-20), because it quotes none.
+3. **The over-rating alarm keeps its numbers** (asked, sent, and which limit cut it), because they are what a fault report needs. `ClampWatchdog.facts` carries them under the same keep-the-bug rule as `reason`, so the words and the numbers always describe the same tick, with asked before sent (SAFETY-40, `test_clamp.py` part 6).
+4. **SAFETY-25 stays in the peak-reserve alarm** as its last sentence ("the reserve only limits peak shaving … down to its cut-out level"). The alarm now gives each branch its own action: at the reserve, lower it; battery level unread, check the sensor; floor unknown, set the cut-out level. That last branch is `soc_floor is None`, which happens when an inverter's cut-out level is missing, not the peak reserve (that option always has a value). Before, every branch said "lower peak_soc_floor". The title, "Battery stopped limiting the peak", is true on all three branches.
+5. **SAFETY-32 at a roster of one.** The body no longer ends in a separate "WHICH PACK" paragraph. The pack's name is part of the first sentence ("The battery of inverter-b …"), and at a roster of one that is the only difference.
+6. **Dropped as background, now in DOCS:** "charging stays blocked" (peak reserve), "why no other guard fired" (circulating power, not delivering), and the saturation-freeze distinction (over-rating). "The meter cannot see this" stays in the circulating-power card, as the owner asked.
+7. **The Details link** opens the add-on's documentation page (`/hassio/addon/<slug>/documentation`, with the slug taken from the container hostname) and names the section. A `#heading` anchor was not used because nobody has checked that Home Assistant's documentation tab renders heading ids; if it does, adding one is a one-line change. Outside an add-on container it names the section without a link.
+
+# Phase 2b: status rows and page banners
+
+Every row of the Commissioning list and every banner is now in `app/messages.py` (`row_*`, `banner_*`), and `test_messages.py` checks a rendering of each. The row and banner kinds are gone from `ux08_allowlist.txt` (200 → 168 entries). DOCS.md "Status page" explains the rows. **Unchanged:** every row's colour (ok / warn / bad), which rows show when, and the banner cascade order.
+
+## Where a choice was made
+1. **A red row may use 3 sentences (30 words).** STYLE.md gave rows 15 words; the owner allows red safety states 3 sentences. A red row needs room for what happened, the state (0 W) and how it clears. STYLE.md now says so, and the test applies it by colour.
+2. **Figures left the rows, not the product.** The reason texts (freeze, sign, circulating, delivery, peak guard) carry reason codes and limits; they stay on the ERROR/WARNING log line and the event list, as before. Rows keep the numbers a reader acts on: the stall age and the 0 W deadline, the meter age and limit, asked and sent for an over-rating, the peak limit, and "opposite for 12 of 60 seconds" while a check counts. So 2a item 2 ("also on the status row") no longer holds, and DOCS.md says "in the add-on log".
+3. **No entity id on any row**, even the green ones that used to print `sensor.x = 54`. The sensor rows name the setting (*Battery power for inverter-b*). Solar sources are numbered in the order of the settings list (*source 2 of 3*, *entry 1 of the reversed-sign list*). This retires TEL-12's rule that a one-entity site reads 0.11.0's sentence byte for byte. A `tools/tel11_pv_trace.py --compare` against a pre-UX-08 tree therefore shows the PV rows as changed telemetry, and the control documents stay equal. The per-source watts and units left the multi-source row. The total, the count and which source is missing remain.
+4. **UX-07 item 1.** `ClampWatchdog` now also counts `over_rating` and `bound` separately. After an episode, each count shows under its own alarm's title ("Power request too high: 2 times since start, not now", "Battery is not keeping up: …"). A site with both gets two amber rows where it had one.
+5. **The "Not ready" banner** is the first red row's own `banner`, or else its first sentence. The peak-reserve and over-rating rows set `banner` to their notification title. The three trips keep their own banner branches, reworded (e.g. "Inverters worked against each other. Every inverter is set to 0 W.").
+6. **How a latch clears stays on the row**, shortened: "Only starting control clears this", "A restart does not clear this", "only stopping and starting control clears this" (not delivering). SAFETY-25's sentence stays on the peak-reserve row.
+7. **Rows got an `id`** (`meter_frozen`, `direction`, `pv`, …), so tests find a row by what it is, not by its words. The page ignores it.
+8. **Left for later:** texts that rows embed from other modules and that were not flagged as rows (the month-peak line, `peakguard.explain()`, the liveness and stale notes, `shadow.banner()`). The month-peak row only lost its semicolons.
+
+# UX-09: fixes after the phase 2a test
+
+1. **The Details link follows the Home Assistant version.** HA 2026.2 added the built-in `app` panel (core #157554, frontend #28245), whose add-on pages are `/config/app/<slug>/documentation`. 2026.5 stopped registering the `hassio` panel, so `/hassio/addon/<slug>/documentation` is a 404 there (TEST-23, HA 2026.9.1). 2026.1 and older have only the old path. The one path valid on both, `/_my_redirect/supervisor_addon?addon=<slug>`, opens the Info tab, not Documentation. So the add-on reads its slug (`GET /addons/self/info`) and the HA version (`GET /info`) at start, and picks the path. An unknown version gets the current path. The hostname stays as a fallback for the slug. Phase 2a item 7 is replaced by this.
+2. **Shadow mode says "would".** The over-rating alarm and row said "sent X W" while 0 W was on the wire, and the peak alarm said "the battery is giving all it can". Both now take `shadow=`, and in shadow mode say what would have been sent and that the inverters stay at 0 W. Severity, id and cadence do not change with the mode.
+3. **"Controller" is gone from texts.** "The add-on" names who decides, and "control" names what it does, as in the existing "start control". The add-on is what the reader sees in Home Assistant, and "controller" was easy to confuse with the control board.
+4. **One term per setting, matching its label.** Four labels changed instead of the texts, because the texts' words were plainer: “Peak reserve (%)” (was "Peak guard will not discharge below"), “Battery level entity (%)” (was "Battery charge level"), and “Solar production entity / entities, per inverter / Reversed-sign solar entities” (was "PV …"). The Dutch labels already said "Zonneproductie". Option descriptions are phase 2c and were not changed, so some still say "PV".
+5. **The shadow banner and the inverter notes** are now `messages.banner_shadow()` and `row_no_setpoint` / `row_not_controllable` / `row_commands_refused`, so `test_messages.py` checks them. The red shadow banner no longer lists the latches, because 12 words cannot carry them. It says a safety stop stays on, and each latch keeps its own red row, which names it and says how it clears. The colour of a liveness row now comes from `is_live()`, not from matching "NOT COMMANDABLE" in the text.
+6. **DOCS "Notifications" and "Status page"** are written for a home owner, and the card ids, keys and log detail moved to a "For installers" part of each.
+
+# UX-08 phase 2c: refusals, error texts and option texts
+
+Validator refusals, the parse errors they carry, and every option name and description are now short. No rule, key, schema, default or exit code changed. Over 36 spoiled configurations the old and new validators refuse the same number of times. The allowlist went from 167 entries to 43, and only log lines (phase 2d) remain on it.
+
+1. **A refusal names the setting by its label and then its key**, as `messages.setting()` writes it: “Inverter rating” (max_w). The key has to stay, because `configui.problems_by_field()` shows a reason beside every key its text names. A test checks each label against en.yaml. A few reasons no longer mention keys they only named in passing, such as `price_markup_eur_kwh` in the withdrawn-provider reason, so the panel shows those reasons beside fewer settings. Each reason still names the setting that fixes it. A setting of one inverter in the list is written “Inverter rating” for inverter-b (inverters.max_w), so the panel shows it beside `inverters`, where that value is changed, and not only beside the flat `max_w` that a list does not read.
+2. **Citations moved to DOCS.** Option descriptions say "Measured value, leave it unchanged" or similar, and the record behind the value is under "For installers: where the numbers come from". The UX-01 citation check in `test_translations.py` now checks the tab for that instruction and DOCS for the record.
+3. **What left the refusals:** the shipped default in the peak-reserve reason, the superseded-default note in the levy-table reason (DOCS already covers it), the endpoints of the withdrawn providers (DOCS "Energy price providers"), the plant measurement behind `slew_w` (DOCS, beside the setting), and the leg-specific paragraphs of the tariff-formula errors. Each reason keeps the rejected value, the limit and what to change.
+4. **Not rewritten:** errors that only a code defect can raise, such as plugin-contract and argument-type checks in `price.py`, `price_forecast.py`, `static_tariff.py`, `arbitrage.py` and `main.py`, which a home owner never reads. INFO lines such as the tariff-formula preview were also left.
+
+# UX-08 phase 2d: log lines, the rest of the status page, and DOCS
+
+The allowlist is empty and its cap is 0 (43 → 0). Every WARNING and ERROR line is one plain line of at most 25 words, with no card ids, capitals or semicolons (the semicolon rule now covers log lines too). **Unchanged:** every log level, every trigger and cadence, every notification id, every row's colour and when it shows, the banner cascade, and every refusal count.
+
+1. **No code prefixes on log lines.** Nothing outside the repositories greps them, except `/home/homelab/clampwatch.sh`, a one-off site watch from 2026-09-05 that greps `OUTPUT_CLAMP` and `Engagements so far`. `OUTPUT_CLAMP` is still in the reason the line quotes; "Engagements so far" is now "Cut back N times so far". The tests that found a line by its card id (`SAFETY-37`, `SAFETY-44`, `CONTROL LOOP DIED`, `UNGRADED`) now find it by its words.
+2. **Reason texts keep their codes.** A line quotes a watchdog's reason (`%s`), such as `STALE_READING: …` or `OUTPUT_CLAMP: …`. Those are the evidence an installer searches for and many tests pin them, so they were not rewritten. The line around them is plain.
+3. **Reasoning moved to DEBUG, not deleted,** for the 10 lines marked DROP-to-DEBUG (for example the 14 768 W history behind the over-rating alarm, why SAFETY-42 reports and does not act, and the Eneco card advice). The 25-word line keeps the action and the numbers. SAFETY-57's promise stays on the ERROR line, as an ordered pair: "until it changes, or 17 s after the command drops below 250 W".
+4. **The line under the buttons** showed the newest raw action-log entry (`OUTPUT_CLAMP …`, `FAILSAFE …: SIGN_DISAGREEMENT`, `ALLOCATOR …`). Each `log_event()` call now also names a plain hint from `messages.HINTS`, and the page shows that. The action log itself is unchanged, because tests and later analysis read it, and the page no longer shows it. It stays reachable as `events` in the `status` JSON (review of #136), because some entries are written nowhere else: a dropped inverter's reason, the unplaced watts, the peak guard's projection and the shadow decision.
+5. **The top table.** *Why* is `messages.why()`: the arbiter's winner and limit in words ("Keeping the grid near zero: 440 W, held back by the peak limit"). `self.reason` keeps `Resolution.explain()` for the log and the checks. *Tariff*, *Price history*, *Arbitrage* and *Shadow mode* keep every figure TARIFF-11 and SAFETY-47 put there, each in its own slot, in words. Labels: *Battery level*, *Solar production*, *Power request*.
+6. **The month-peak row became two rows**, because one sentence of 15 words cannot hold the peak, its time, its share of the limit and TARIFF-13's coverage figure. The store's state at start (`restore_state`) left the row: it is the INFO line at start.
+7. **The peak guard rows** name the projection first and the limit second, as before (SAFETY-38). The blind row says what it means for the owner: the battery does not charge until the period can be measured again.
+8. **Wording that changed meaning-carrying words**: "command and meter point opposite ways" is now "the power went the wrong way" (banner) and "…went against what the add-on asked" (row). The N=1 banner still names the meter, the N≥2 texts still say "own power". The inverter range reads "up to 5 000 W each way" instead of "-5 000 W to 5 000 W".
+9. **Refusals are counted as shown.** Setting placeholders are expanded to label and key, and the long cases the 2c test found are driven through the validator. Seven refusals were shortened. The card refusals no longer show `c_eur_per_kwh`, `vat_pct` or "its own card", and a text that does not parse says "not valid near character N" instead of the parser's words. A missing value shows as *empty*, not `None`.
+10. **The panel's key match** no longer files `inverters.max_w` under the flat `max_w`.
+11. **The Supervisor question at start** is one INFO line with a real reason (a timeout's own text is empty, so the error type is named).
+12. **DOCS**: a glossary ("Words used on this page") explains control board, isolator and Developer Tools once. Card ids left the headings and sit on a *For installers* line under each. The links to the renamed headings were updated.

goodwe_controller/MUTATION.md

@@ -172,7 +172,7 @@ manufactures them from a **fixture**: the check runs, the assertion is
 evaluated, the sentence above it is true — and the numbers it compares are
 arranged so that the failure it describes could not have changed the answer.
 
-It is not hypothetical and it is not rare. ELEVEN instances in two weeks; four
+It is not hypothetical and it is not rare. TWELVE instances in two weeks; four
 were found by review, two - CFG-04's fixture pair - by an author's own mutation
 battery, which is the cheaper place, one by review again, in the one
 place nobody had thought to point the rule at: not a check in the suite, but a
@@ -414,6 +414,44 @@ same place twice, the check is decoration.
 
   The general habits are **14** and **15** below.
 
+* ⚠️ **SAFETY-47 IS THE TWELFTH, AND IT IS THE SECOND INSIDE A COMMITTED
+  EVIDENCE ARTIFACT.** `DECISIONS/SAFETY-10-shadow-mode.md` §6 tabulated a live
+  run and a shadow run agreeing on `arb_power_w`, on the reason **verbatim**
+  and on the arbiter's winner, and concluded that shadow mode reaches the same
+  decision. **Two independent reasons it could not have gone red, and closing
+  either one alone closes nothing:**
+  * its fixture is `peak_cap_w: 15000` against a 350 W house, so the capacity
+    guard never engages and the thing whose invariance is being claimed —
+    SAFETY-45's sizing of the buy leg from the billed-quarter meter — is in the
+    run and **inert**. ⚠️ **The harness's own comment says so**: *"at this
+    scenario's `peak_cap_w: 15000` it is not binding anyway"*. The rule was
+    written down beside the check it disabled and nobody read it as a
+    disclosure;
+  * and every identity row reads `_sa[0]`/`_la[0]` — **the first charging
+    sample**. At `elapsed = 0` the projection **is** the held level, so the two
+    runs agree **to the float even at a cap that does bind**. Measured:
+    widening the fixture alone — the obvious fix — leaves that comparison
+    passing.
+
+  ⚠️ **THE SECOND REASON IS A NEW SHAPE FOR THIS LIST: AN INDEX, NOT A
+  FIXTURE.** Ask of every identity claim not only *"could this data differ"*
+  but *"**at the point I sampled it**, could it differ yet"*. A comparison
+  taken at `t = 0` between two runs that diverge **because one of them acts**
+  is a comparison of a plant with itself, and no amount of widening the fixture
+  changes that. The replacement, `test_arbitrage.py` part 3d, grades the whole
+  run — 716 of 720 charging cycles differ — and grades the `[0]` agreement **as
+  an expectation**, so nobody rebuilds a check on it believing it covers
+  something.
+
+  ⚠️ **AND THE FIX'S OWN FIRST DRAFT CARRIED A THIRTEENTH.** The new part's
+  action-log check could not reach the log line at all: the sentence was an
+  f-string inside `Controller._shadow_settle()`, and the only suite that drives
+  that method uses a `meter_source: off` fixture where no arbitrage decision —
+  and therefore no caveat — exists. Deleting the caveat from it left **all 29
+  files green**. It is `shadow.log_line()` now. *A sentence assembled at a call
+  site is a sentence no check can grade*, which is CFG-04's substring lesson
+  arriving from the other direction.
+
 Note what these have in common with a masked rung: the mutation *runs*, and the
 suite is *honestly* green. Nothing in a purge, a fingerprint or a disassembly
 can see it, because the code under test really did behave identically on the
@@ -773,6 +811,177 @@ Cheap habits fall out of it, and all of them are now used in this repository:
     retrofitted: guarding another card's section is a change to what its
     checks report, and it belongs to whoever next touches it.
 
+21. ⚠️ **A CHECK CAN BE GREEN UNDER ITS OWN CARD'S NAMED MUTATION, AND TWICE
+    IN ONE FILE THE REASON WAS THAT THE WRONG QUANTITY EVENTUALLY REACHES THE
+    RIGHT VALUE.** TEL-10's acceptance was *"a run that winds the integrator
+    into the bound must show the published number reaching the bound"*, and its
+    named mutation was *"publish `prev_w` instead of `i_w`"*. The check was
+    **GREEN** on the mutant: the command reaches the same bound too, twelve
+    cycles later, and a check that only reads the VALUE cannot tell the two
+    apart. The same file's *"a stopped controller publishes `not-running`"* was
+    green under deleting that branch's assignments outright (−45 B and −67 B),
+    because the fixture STARTED stopped and `__init__` writes the same values.
+    Both are habit 4 - the data could not reach the failure - and both were
+    found by the card's own battery. The fixes are the shape to copy:
+    * where two quantities CONVERGE, grade the **order or the interval**, not
+      the value: "the integrator reaches the bound BEFORE the command does",
+      and a PLATEAU (the lead sits at exactly −800 W for eight consecutive
+      cycles) rather than a maximum, because a maximum is one tick and a
+      plateau is the shape;
+    * where a branch WRITES a value the constructor also writes, the fixture
+      has to pass THROUGH the other state first. Stop the controller part-way
+      through a run that has already wound the integrator to −5000 W, so a row
+      left standing is a WRONG row and not merely an unset one.
+
+22. ⚠️ **AN EXPLANATION IN A COMMENT IS A CLAIM, AND SAFETY-48 SHIPPED TWO THAT
+    WERE INVENTED.** A gate was written one-sided (`if target > slewed: min(...)
+    elif target < slewed: max(...)`) under a comment saying the two-sided band
+    `max(lo, min(hi, i_w))` was a BUG that would drag a trailing integrator
+    toward the command, with a worked example. It is not a bug and the example
+    was wrong: `target` is monotone in `i_w`, so the other clamp cannot reach,
+    and the two spellings agree on **205 920 of 205 920** swept states. A second
+    bullet said two placements of the same cap *"differ on 118 of 256 252
+    ticks"*; that 118 had been measured against a **different pair** and the
+    placement actually being compared is bit-identical on the shipped
+    configuration - 0 of 256 246 ticks. Both sentences were plausible, both were
+    load-bearing for a design choice, and neither had been run.
+    **The rule: a comment that says "X would be wrong" is subject to the same
+    battery as a check - BUILD X AND MEASURE IT.** Where the answer is
+    "equivalent", say so with the sweep size and keep the spelling for what it
+    NAMES; where the answer is a number, quote the run it came from. An
+    invented justification for a correct decision is still a defect, and it is
+    the kind a reviewer cannot see because the code is right.
+
+23. ⚠️ **THE MUTATION IS SUBJECT TO EVERY HABIT ABOVE, HABIT 4 INCLUDED - AND
+    THE PURGE, THE FINGERPRINT AND THE BYTE DELTA ALL SAY IT TOOK.** SAFETY-57's
+    battery reported a **survivor at +21 B** for a mutation of
+    `Freshness._open_window()`: `self.graded_from = float(now_mono)` rewritten
+    as `float(self.changed_mono or now_mono)`, which is meant to re-anchor the
+    verdict's window to the register's own history and so delete the card's
+    whole exit. The harness purged, the tree fingerprint showed the edit on
+    disk, the delta was non-zero, and the mutant really did run. It was still a
+    survivor for a reason that has nothing to do with the property: in the
+    fixture the register never moves after `t = 0`, so `changed_mono` is
+    **`0.0`** - and `0.0 or x` is `x`. **The mutant was a no-op on that
+    stimulus.** Rewritten with an explicit `is None` test (+82 B) it is red on
+    four named checks.
+
+    Stale bytecode is a mutation that never *ran*. This is a mutation that ran
+    and could not *change the answer* on the data it was given, which is habit 4
+    exactly, one level up - and none of the three things a mutation report is
+    required to state (MUTATION.md's own list) can see it, because all three are
+    about the file rather than about the stimulus. Two rules:
+    * **Ask of every survivor what it would have had to change, and check that
+      the fixture reaches that value.** Here: "does any fixture have a non-zero
+      `changed_mono` at the moment `_open_window()` is called?" The answer was
+      no, and it is one line to ask.
+    * **Prefer a mutation that CANNOT be a no-op.** `or`, `and`, truthiness on
+      a numeric, a default argument and a `getattr` fallback all have a value at
+      which the mutant and the shipped tree coincide. An explicit comparison,
+      a constant swap or a deleted statement does not.
+
+    ⚠️ Note where this one was found: in the battery of a card whose whole
+    subject is a check that cannot reach the failure it names. **Second
+    instance in an instrument rather than in a check since habit 16, and the
+    third overall.**
+
+    ⚠️ **AND THE SAME CARD'S BATTERY CAUGHT A HABIT-22 COMMENT IN THE FIX
+    ITSELF, WHICH IS WHY THESE TWO BELONG NEXT TO EACH OTHER.**
+    `freshness.py` shipped `⚠️ RELEASE BEFORE GRADE, AND THE ORDER IS
+    LOAD-BEARING` with a worked reason. Swapping the two calls is **zero bytes**
+    and survived the battery: `_grade()` acts only when `|standing| >= move_w`
+    and `_release()` only when `|standing| < move_w`, so at most one can act on
+    any read and the order is **not observable**. Habit 22 says build X and
+    measure it; the battery is what builds X. The comment now states the
+    disjointness and the suite pins **that** - at 0, 100, 249, 250, 251 and
+    1300 W - rather than an order nothing depends on.
+
+    ⚠️ **SECOND INSTANCE, TEL-11, AND THE NO-OP WAS A SATURATED RAIL RATHER
+    THAN A VALUE.** The card's whole subject is that a PV reading must never
+    reach the control law, so its central mutation is
+    `self.grid = self.grid - self.pv_w` in `read_inputs()` - **+106 B**, on
+    disk, purged, genuinely running - and it came back a **SURVIVOR** of a
+    six-file battery. The property held in no sense: the fixture drove a 6 kW
+    export over 12 cycles, which puts the loop **against its rail**, and a
+    command moving `slew_w` every cycle produces the SAME ramp for -6000 W and
+    for -14000 W of apparent error. The mutant ran and could not change the
+    answer.
+    Two things generalise past PV:
+    * **A SATURATED ACTUATOR IS A VALUE AT WHICH EVERY INPUT COINCIDES.** The
+      habit-23 list above names `or`, `and`, truthiness, default arguments and
+      `getattr` fallbacks - all *expressions* with a coinciding value. A rail,
+      a clamp, a slew limit, a deadband and a latched alarm are the same hazard
+      in the **plant**: they are where a controller's output stops being a
+      function of its input. A fixture that parks there cannot separate any two
+      inputs, and this repository's control fixtures park there by default,
+      because the dramatic stimulus is the saturating one.
+    * **SO THE PRECONDITION IS NOT "DOES IT COMMAND SOMETHING", IT IS "DOES IT
+      REST SOMEWHERE THE MUTATION COULD MOVE IT FROM".** `test_pv.py` part 6
+      now drives a 600 W import the loop SETTLES on, asserts the resting target
+      is well inside the rail, and asks habit 23's own question as a check:
+      shift the METER by the same 8 kW and confirm the commands really would
+      have moved. On the first fixture that question answers NO, in one line,
+      and it is the line that turns the identity into evidence.
+
+24. **A REFUSAL DEFINED RELATIVE TO "THE BASELINE LACKS THIS FEATURE" DIES ON
+    THE RELEASE THAT SHIPS THE FEATURE — AND IT DIES AS A FALSE REFUSAL, WHICH
+    IS THE LOUD DIRECTION.** TEL-11 built `tools/tel11_pv_trace.py` to grade a
+    cross-tree identity, and because "the documents are identical" was its
+    *result* rather than its warning sign, it had to prove instead that the two
+    runs came from different trees and that **exactly one side reacts to
+    `pv_entity`**. That was correct evidence: `release/1.0` predated the option
+    entirely, so a side that reacted to it was the HEAD by construction.
+
+    TEL-11 then **merged**, `release/1.0` became 0.11.0, and the baseline for
+    the next card reacts to `pv_entity` too. `--compare` now answers
+    `REFUSED: set differs from unset on ['A', 'B']` on every honest run — the
+    instrument refuses its own shipped tree. TEL-12 found it on the first
+    comparison it ran.
+
+    * **A discriminator is a fact about a MOMENT, not about a card.** "The
+      baseline does not have X" is true until X ships and then false forever.
+      Write the discriminator against something the NEXT baseline still will not
+      have — TEL-12's is the roster key, not the channel — and say in the tool
+      which fact it rests on, so the next card can see what it has to replace.
+    * **Prefer a discriminator that is MEASURED over one the tree REPORTS.**
+      `tree.supports_roster` is the tree describing itself and would have been
+      one line; the shipped test is "this side's roster cells ARE its unset
+      cells", which is the tree being measured. Both are printed, side by side,
+      so a disagreement between the self-report and the measurement is visible
+      rather than silently trusted.
+    * ⚠️ **And this is the SAFE direction of the same defect, which is why it
+      was found in ten minutes rather than in a review.** A stale refusal is a
+      developer chasing a failure they cannot explain (the false-red case at the
+      top of this file). A stale *identity* — an instrument that goes on printing
+      OK because its reference drifted into agreement — is the survivor-
+      manufacturing direction, and nothing announces it. Ask of every cross-tree
+      instrument: *what does this print when the feature it is about has been in
+      the baseline for a year?*
+
+    TEL-12's own battery produced two more instrument defects of the ordinary
+    kind, both recorded in `DECISIONS/TEL-12-several-pv-inverters.md` §4: a
+    stimulus annotation written into the document being compared (so every cell
+    differed for a reason that was not behaviour, and the discriminator fired on
+    both sides), and a fixture cell whose TRUE total was labelled as its
+    "partial" (so the check refused the shipped tree for publishing a number it
+    is required to publish). ⚠️ **Both were caught by running the instrument
+    against the shipped tree BEFORE running it against a mutant** — which is the
+    one ordering rule that separates "the instrument is wrong" from "the tree is
+    wrong", and `test_mqtt.py` part 8's first line ("the shipped module satisfies
+    every property this instrument grades") is the same rule as a check.
+
+    ⚠️ **AND TEL-12's SUBJECT WAS HABIT 23 IN THE FIXTURE ITSELF.** The card adds
+    a SUM over a roster, and the defect it exists to prevent is publishing the
+    partial sum when a member is absent. A fixture whose absent member
+    contributes **0 W** cannot see that defect at all: the partial and the full
+    total are **the same number**, so "published the absence" and "published the
+    partial" produce identical output. That is a rail in the *arithmetic* rather
+    than in the plant — the same hazard as TEL-11's saturated actuator, one
+    domain over. `test_pv.py`'s roster is three distinct non-zero contributions
+    in two different units, absence is driven at **every position** rather than
+    at one (habit 10), and each position's partial is **computed from the
+    fixture** and asserted to differ from the true total as its own precondition.
+
 And the mutation-table consequence: **a variant is not covered because a
 near-miss of it is.** DEV-02's table listed the *actuator* variant of the
 per-unit claim defect (`device`/`supervised` filed without `inv`), which the
@@ -831,13 +1040,16 @@ document (`'  216.080 ->   0.30123'`), and M13 is red.
 
 **M10 is `+0 B` and it is a real defect, not a synthetic one.** It came out of
 writing the mutation rather than out of review: `implausible_all_in()`'s floor
-was applied to the all-in figure, and `price_taxes_eur_kwh` ships at 0.06 —
+was applied to the all-in figure, and `price_taxes_eur_kwh` shipped at 0.06 —
 **three times the 0.02 floor** — so a card read a hundred times too small
 (0.0016 EUR/kWh of energy) is carried over the floor by the flat tax addend
 alone and passes. The hundredfold error is exactly what that band exists for.
 The floor is applied to the **energy** figure now and the ceiling to the all-in
 one, both directions are graded, and the trap is stated as a check in its own
-right so the asymmetry cannot be "tidied up" later.
+right so the asymmetry cannot be "tidied up" later. *(Annotated 2026-09-13:
+TARIFF-18 raised that default to 0.11736, **nearly six times** the floor. The
+addend that does the carrying got BIGGER, so the trap is wider than when M10
+was measured and the asymmetry is more load-bearing rather than less.)*
 
 **M15 is the one the framework CANNOT catch, and the reds say which half does.**
 Declaring `ALL_IN` makes `assemble()` add nothing, and section 3's all-in check

goodwe_controller/app/arbitrage.py

@@ -184,6 +184,17 @@ IDLE_OFF_PEAK_HOUR = "this hour is neither the buy hour nor the sell hour"
 IDLE_NO_SIZE = (
     "no pack's state of charge permits this side of the trade, so it is sized "
     "at 0 W - and a 0 W arbitrage claim is a park order, not a trade")
+# SAFETY-45. THE BUY LEG'S SIZE, AND ONLY THE BUY LEG'S - §9.1: "Discharge and
+# export are never capped by the peak guard; only charging and import are."
+IDLE_NO_HEADROOM = (
+    "the capacity-tariff guard has measured this billed quarter and it can "
+    "afford no charging at all, so a trade of any size would push it over the "
+    "ceiling - and a 0 W arbitrage claim is a park order, not a trade")
+IDLE_HEADROOM_UNMEASURED = (
+    "the capacity-tariff guard did not size this quarter's charging headroom "
+    "this cycle, and an UNMEASURED headroom is not an unlimited one - charging "
+    "creates the billed quantity (§9.1) and nothing is measuring the quarter "
+    "this one would land in")
 NEGATIVE_PRICE = (
     "§17: the sell hour is priced BELOW ZERO, so discharging into it would give "
     "energy away and pay for the privilege. Arbitrage must not export at a "
@@ -251,10 +262,8 @@ def threshold_eur_kwh(opts: dict) -> float:
     v = float(price_option(opts, "cycle_cost_threshold_eur"))
     if not math.isfinite(v) or v < 0:
         raise ValueError(
-            f"cycle_cost_threshold_eur is {v!r}. It is what a round trip COSTS, "
-            f"in EUR/kWh, so it is non-negative and finite - a negative "
-            f"threshold is one every spread clears, which is arbitrage with the "
-            f"brake removed.")
+            f"“Battery cycle cost” (cycle_cost_threshold_eur) is {v!r}. Set "
+            f"it to 0 or more, in EUR/kWh.")
     return v
 
 
@@ -303,7 +312,7 @@ def _point_at(plan, when: datetime):
         return None
 
 
-def decide(plan, now: datetime, *, peak_guard_active, soc,
+def decide(plan, now: datetime, *, peak_guard_active, charge_headroom_w, soc,
            min_spread_eur_kwh, uncertainty, charge_w, discharge_w,
            soc_floor_pct, soc_ceiling_pct) -> ArbitrageDecision:
     """Should the battery trade this cycle, and how hard.
@@ -314,6 +323,18 @@ def decide(plan, now: datetime, *, peak_guard_active, soc,
     None refuses, because the alternative is a strategy that creates the billed
     quantity while the thing that would have limited it is switched off.
 
+    ⚠️ `charge_headroom_w` IS SAFETY-45's SECOND, CONTINUOUS ANSWER FROM THE
+    SAME GUARD, AND IT IS NOT A DUPLICATE OF THE FIRST. `peak_guard_active` is a
+    SWITCH - it says whether the guard is holding - and a switch keyed on a
+    continuous quantity is what made the loop oscillate: the guard engaged at a
+    5 W floor, this module refused the whole trade, the loop took the actuator,
+    the meter fell, the guard released and the trade re-armed AT FULL POWER
+    130 s later. 28 times an hour, measured. `peakguard.charge_headroom_w()` is
+    the watts the billed quarter can still afford; sizing the buy leg to it means
+    the trade is CLAMPED rather than switched, which is the same shape
+    `control.maintenance_charge_floor()` has always given a maintenance charge.
+    ⚠️ None IS NOT UNLIMITED here either - see IDLE_HEADROOM_UNMEASURED.
+
     ⚠️ EVERY OTHER ARGUMENT IS KEYWORD-ONLY AND HAS NO DEFAULT, for
     `TariffPlan.arbitrage()`'s reason. A defaulted `soc_floor_pct` is a reserve
     floor this module asserted rather than one the operator configured, and the
@@ -330,10 +351,12 @@ def decide(plan, now: datetime, *, peak_guard_active, soc,
     return verdict.match(
         refused=lambda v: _idle(v.reason),
         allowed=lambda v: _act(plan, now, v, soc, charge_w, discharge_w,
-                               soc_floor_pct, soc_ceiling_pct))
+                               soc_floor_pct, soc_ceiling_pct,
+                               charge_headroom_w))
 
 
-def _act(plan, now, v, soc, charge_w, discharge_w, floor_pct, ceiling_pct):
+def _act(plan, now, v, soc, charge_w, discharge_w, floor_pct, ceiling_pct,
+         headroom_w):
     """The permitted case: which hour is this, and may the pack do it."""
     here = _point_at(plan, now)
     if here is None:
@@ -403,18 +426,110 @@ def _act(plan, now, v, soc, charge_w, discharge_w, floor_pct, ceiling_pct):
             f"nowhere to put the cheap energy", **common)
     if not abs(float(charge_w)) > 0.0:
         return _idle(IDLE_NO_SIZE, **common)
+    # SAFETY-45. THE BILLED QUARTER IS ASKED LAST, AND THE PLACEMENT IS
+    # DELIBERATE: every refusal that existed before this card keeps the
+    # precedence it had, so no sentence an operator already reads changes when
+    # it fires, and the two added here are placed where they cannot displace
+    # one. The pack's reasons come first because they are properties of the
+    # hardware in the cupboard; this one is a property of the fifteen minutes
+    # the trade would land in.
+    if headroom_w is None:
+        # ⚠️ NOT "the guard is clear". This is `guard_state()`'s None argument
+        # one layer down: a headroom nothing measured is not an unlimited one,
+        # and charging at max_w creates the billed quantity (§9.1).
+        return _idle(IDLE_HEADROOM_UNMEASURED, **common)
+    asked_w = abs(float(charge_w))
+    size_w = min(asked_w, max(0.0, float(headroom_w)))
+    if not size_w > 0.0:
+        # ⚠️ NOT IDLE_NO_SIZE, WHICH IS THE LINE ABOVE AND BLAMES THE PACKS.
+        # `asked_w > 0` is already established here, so the pack may be empty
+        # and willing and it is the billed quarter that has run out. A refusal
+        # naming the wrong subsystem sends an operator to the wrong page
+        # (§10.2), and these two are a whole quarter-hour apart in what they
+        # ask a human to do about them.
+        return _idle(IDLE_NO_HEADROOM, **common)
+    # ⚠️ THE SENTENCE CARRIES BOTH NUMBERS IN THEIR OWN SLOTS, not one figure
+    # twice. MUTATION.md habit 14: two values in one sentence can be transposed
+    # by a ZERO-BYTE edit that no byte delta and no shape pin can see, so the
+    # trade's own size and the guard's headroom are each named by the literal
+    # text around them.
+    capped = size_w < asked_w
     return ArbitrageDecision(
-        action=CHARGE, power_w=-abs(float(charge_w)),
+        action=CHARGE, power_w=-size_w,
         reason=(f"{CHARGE}: this is the cheapest firm hour at "
                 f"{price:.4f} EUR/kWh, {v.spread_eur_kwh:.4f} below the dearest "
                 f"and clear of the {v.required_spread_eur_kwh:.4f} this cycle "
-                f"had to cover; charging {abs(float(charge_w)):.0f} W from "
-                f"{soc:g} %"),
+                f"had to cover; charging {size_w:.0f} W from {soc:g} %"
+                + (f" - SIZED BY THE CAPACITY-TARIFF GUARD: the trade asked for "
+                   f"{asked_w:.0f} W and this billed quarter can afford "
+                   f"{float(headroom_w):.0f} W (§9.1, §10.1 priority 2)"
+                   if capped else "")),
         spread_eur_kwh=v.spread_eur_kwh,
         required_eur_kwh=v.required_spread_eur_kwh,
         price_now_eur_kwh=price)
 
 
+def sized_from_meter(decision: ArbitrageDecision, headroom_w, *,
+                     winner: str | None) -> bool:
+    """SAFETY-47. Was the number a shadow run just recorded SIZED FROM THE
+    BILLED QUARTER - i.e. from a measurement of what the battery itself did?
+
+    THE ONE PLACE THIS QUESTION IS ANSWERED, and it is public for the reason
+    `peakguard.charge_headroom_w()`, `discharge_permitted()` and
+    `freeze.looks_frozen()` are: the check that grades it has to assert on THE
+    SHIPPED EXPRESSION. A predicate transcribed into its own test is one copy
+    plus a future disagreement about what the check means.
+
+    ------------------------------------------------------------------------
+    THE DEFECT IT PREVENTS
+
+    `shadow.words()` and the action log carry "would have commanded N W". In
+    SHADOW MODE the battery is held at `shadow.WIRE_W`, so the billed quarter
+    the buy leg was sized against contains THE HOUSE AND NOTHING ELSE - while
+    a live run's meter rises as the trade charges. The same code, the same
+    hour, `peak_cap_w` 1500 under a 1200 W house: live commands -302.4 W and a
+    shadow run records -2000.0 W. 6.61x, on the status row, with no caveat.
+    This is the flag that puts the caveat there.
+
+    ⚠️ IT IS TRUE WHENEVER A MEASURED HEADROOM ENTERED THE ARITHMETIC, NOT
+    ONLY WHEN IT BOUND. `_act()` sizes the buy leg as `min(asked, headroom)`,
+    and "the headroom did not bind" is ITSELF a measured fact about a quarter
+    the battery never entered. Keying this on `capped` - on whether the
+    shipped sentence says "SIZED BY THE CAPACITY-TARIFF GUARD" - would answer
+    True at the START of the quarter, where a shadow run and a live run still
+    agree to the watt, and False at the END, where `(900/remaining)` has
+    multiplied the headroom past the ask and the recorded number is at its
+    most wrong. The quietest caveat exactly where it is needed loudest.
+
+    ⚠️ THE BUY LEG ONLY. §9.1: "Discharge and export are never capped by the
+    peak guard; only charging and import are." A sell is sized from
+    `discharge_w`, which is the roster's own rating and not a measurement of
+    the quarter, so a sell's recorded watts are NOT subject to this and must
+    not carry a caveat that would then be false.
+
+    ⚠️ AND THE ARBITER'S WINNER IS THE THIRD RUNG, NOT AN AFTERTHOUGHT. A trade
+    that was sized from the meter and then OUT-RANKED is not the number being
+    recorded - `Resolution.target_w` belongs to somebody else - and a caveat
+    filed against somebody else's number is a false sentence on the status row,
+    which is the defect class this whole card is about. It is in HERE and not
+    in `main.py` for the reason the two rungs above are: all three answer one
+    question, a check has to be able to reach each of them with the other two
+    clear (TEST-16), and a rung that lives at a call site is a rung no check
+    can drive.
+
+    `headroom_w` is whatever `peakguard.charge_headroom_w()` answered for the
+    cycle this decision was taken on. ⚠️ None IS "NOTHING MEASURED IT", and
+    `decide()` REFUSES the trade there (IDLE_HEADROOM_UNMEASURED), so a None
+    can only ever arrive here beside a non-trading decision - but it is tested
+    rather than assumed, because the caller is `main.py` and not this module.
+
+    `winner` is `Resolution.winner`: the source that actually set the watts.
+    """
+    return (winner == SOURCE
+            and decision is not None and decision.action == CHARGE
+            and headroom_w is not None)
+
+
 def claim(decision: ArbitrageDecision) -> Claim | None:
     """The decision as one arbiter claim, or None when nothing is to be traded.
 

goodwe_controller/app/clamp.py

@@ -73,6 +73,7 @@ An alarm wired only to this module's `ClampResult.engaged` would therefore be
 silent on the exact configuration the whole ticket is about. The winding is
 visible one layer up, at the integrator bound, and that is why `Decision` now
 carries `i_clamped` / `clamped` BOOLEANS and the caller ORs them in here.
+They alarm in different words: see `loop_clamp_note()` (SAFETY-40).
 
 AND WHY BOOLEANS RATHER THAN `Decision.reason`. `reason` is a single string that
 later stages overwrite: a cycle that clamps the integrator and is then slew
@@ -200,9 +201,8 @@ REASON_CODE = "OUTPUT_CLAMP"
 # ceiling rests on one number a test author chose; if that number is ever
 # revisited, this constant moves with it.
 #
-# ⚠️ THIS IS A STOP-GAP AND DOES NOT MAKE THE ALARM CORRECT. The message still
-# calls the integrator bound a BUG SIGNAL and still pairs a request from one
-# moment with a `self.target` read at another - SAFETY-40. Nothing here is
+# ⚠️ THIS WAS A STOP-GAP; the wording and the numbers were SAFETY-40's, fixed
+# in `loop_clamp_note()` below. Nothing here is
 # suppressed: every engagement is still counted, the action-log row is written on
 # every engaged cycle regardless, and the rising edge of every episode alarms
 # unconditionally, so no alarm is DROPPED - only delayed.
@@ -234,6 +234,31 @@ CLEAR_CYCLES = 3
 SUSTAINED_CYCLES = 3
 
 
+BUG_SIGNAL = ("This is a BUG SIGNAL, not a limit being used: something "
+              "upstream computed a setpoint the actuator cannot deliver.")
+
+
+def loop_clamp_note(d) -> str:
+    """The loop-side alarm text for one `control.Decision`, or "".
+
+    SAFETY-40: the integrator bound is anti-windup doing its job and says so;
+    only a command over the rating is a BUG SIGNAL. Every number is the
+    decision's own, i.e. from the tick that clamped.
+    """
+    if d.clamped:
+        return (f"{REASON_CODE}: the loop computed {d.requested_w:+.0f} W, over "
+                f"the {abs(d.clamped_w):.0f} W rating, and it was clamped to "
+                f"{d.clamped_w:+.0f} W; the loop's command this cycle was "
+                f"{d.target_w:+.0f} W. {BUG_SIGNAL}")
+    if d.i_clamped:
+        return (f"{REASON_CODE}: the loop's integrator reached its "
+                f"{d.i_bound_w:+.0f} W anti-windup bound; the loop's command "
+                f"this cycle was {d.target_w:+.0f} W. Brief "
+                f"engagements after a large load or solar step are normal. If it "
+                f"persists, check that the battery is following its commands.")
+    return ""
+
+
 @dataclass(frozen=True)
 class ClampResult:
     """What the guard did, with the RAW value preserved.
@@ -333,32 +358,72 @@ class ClampWatchdog:
     def __init__(self):
         self.active = False
         self.engagements = 0      # every engagement, never deduplicated
+        # UX-08: the same count split by alarm type, so the status page names
+        # each with its own alarm's title after the episode clears.
+        self.over_rating = 0      # bug=True: "Power request too high"
+        self.bound = 0            # bug=False: "Battery is not keeping up"
         self.episodes = 0         # rising edges
         self.since: datetime | None = None
         self.last_alarm: datetime | None = None
         self.reason = ""
+        # UX-08: the numbers behind `reason`, for the notification - set under
+        # the same rule as `reason`, so both always describe the same tick.
+        self.facts = ()
         self.clean_cycles = 0
         # SAFETY-41. Consecutive engaged cycles, and whether THIS episode has
         # spoken yet - the two the escalation clause needs.
         self.run_len = 0
         self.spoken = False
+        # SAFETY-40. Did this episode include a genuine over-rating (`bug`), and
+        # has THAT spoken? A bug has its own budget, so anti-windup notices can
+        # never delay it; with bug=True throughout, cadence is as before.
+        self.bug = False
+        self.bug_spoken = False
+        self.last_bug_alarm: datetime | None = None
 
-    def note(self, engaged: bool, reason: str, now: datetime) -> bool:
+    def _due(self, last, now) -> bool:
+        return last is None or (now - last).total_seconds() >= REASSERT_S
+
+    def _speak(self, now, bug) -> bool:
+        self.last_alarm = now
+        self.spoken = True
+        if bug:
+            self.last_bug_alarm = now
+            self.bug_spoken = True
+        return True
+
+    def note(self, engaged: bool, reason: str, now: datetime,
+             bug: bool = True, facts=()) -> bool:
         """Advance one cycle. True when the caller should raise the alarm.
 
         `now` is the caller's clock, the same discipline as
-        `SignWatchdog.evaluate()` and `FreezeWatchdog.evaluate()`.
+        `SignWatchdog.evaluate()` and `FreezeWatchdog.evaluate()`. `bug` False
+        is the integrator bound (SAFETY-40): counted and notified like the
+        rest, but it never replaces a bug's text within an episode.
         """
         if engaged:
             self.engagements += 1
+            if bug:
+                self.over_rating += 1
+            else:
+                self.bound += 1
             self.clean_cycles = 0
-            self.reason = reason
             self.run_len += 1
-            if not self.active:
+            rising = not self.active
+            if rising:
                 self.active = True
                 self.since = now
                 self.episodes += 1
                 self.spoken = False
+                self.bug = False
+                self.bug_spoken = False
+            if bug or not self.bug:
+                self.reason = reason
+                self.facts = tuple(facts)
+            self.bug = self.bug or bug
+            if bug and not self.bug_spoken and self._due(self.last_bug_alarm, now):
+                return self._speak(now, True)
+            if rising:
                 # ⚠️ SAFETY-41. THE RISING EDGE IS RATE-LIMITED TOO, and it did
                 # not used to be. It fired unconditionally, so a condition that
                 # engages and clears repeatedly raised one notification PER
@@ -384,11 +449,8 @@ class ClampWatchdog:
                 # still written on every engaged cycle, and a genuine runaway -
                 # which by definition keeps engaging - is picked up by the
                 # re-assert path within REASSERT_S. Delay, not loss.
-                if (self.last_alarm is None
-                        or (now - self.last_alarm).total_seconds() >= REASSERT_S):
-                    self.last_alarm = now
-                    self.spoken = True
-                    return True
+                if self._due(self.last_alarm, now):
+                    return self._speak(now, self.bug)
                 return False
             # ⚠️ THE ESCALATION. An episode that has not yet spoken because the
             # budget was spent by an EARLIER, unrelated episode speaks anyway
@@ -396,15 +458,10 @@ class ClampWatchdog:
             # engages every cycle and reaches it; the scattered one-cycle
             # railing that produced the live flood never does.
             if not self.spoken and self.run_len >= SUSTAINED_CYCLES:
-                self.last_alarm = now
-                self.spoken = True
-                return True
+                return self._speak(now, self.bug)
             # Still engaged: re-assert on the slow cadence, not every cycle.
-            if (self.last_alarm is None
-                    or (now - self.last_alarm).total_seconds() >= REASSERT_S):
-                self.last_alarm = now
-                self.spoken = True
-                return True
+            if self._due(self.last_alarm, now):
+                return self._speak(now, self.bug)
             return False
 
         self.run_len = 0
@@ -420,5 +477,7 @@ class ClampWatchdog:
             # above. The episode ends; the notification budget does not reset
             # with it.
             self.reason = ""
+            self.facts = ()
+            self.bug = False
             self.clean_cycles = 0
         return False

goodwe_controller/app/config_page.py

@@ -413,10 +413,9 @@ function showProblems(payload){
   save.disabled = total > 0;
   if(total){
     note(banner, 'bad', 'This configuration would not start.',
-      'The add-on refuses to run on it and would stop with exit 78. '
-      + 'Saving is blocked until these are fixed; nothing has been written. '
-      + 'Each message below is the add-on\\u2019s own words, from the same '
-      + 'check that runs at startup.');
+      'The add-on would refuse to start on it. Saving is blocked until these '
+      + 'are fixed, and nothing has been written. Each message below comes '
+      + 'from the same check that runs at start.');
     banner.insertBefore(banner.lastChild, banner.firstChild);
     msg(total + (total === 1 ? ' problem' : ' problems')
         + ' - saving is blocked', 'bad');

goodwe_controller/app/configui.py

@@ -289,7 +289,10 @@ def problems_by_field(problems, keys):
     cross-field rule is about all of its fields, and hiding it from one of them
     would be this card's own defect in miniature.
     """
-    patterns = [(key, re.compile(r"(?<![A-Za-z0-9_])" + re.escape(key)
+    # ⚠️ `.` BEFORE THE KEY DOES NOT COUNT (UX-08 2d): `inverters.max_w`
+    # names a setting of one inverter in the list, which is changed under
+    # `inverters`, and it must not also land beside the flat `max_w`.
+    patterns = [(key, re.compile(r"(?<![A-Za-z0-9_.])" + re.escape(key)
                                  + r"(?![A-Za-z0-9_])")) for key in keys]
     by_key, unanchored = {}, []
     for problem in problems:

goodwe_controller/app/control.py

@@ -191,6 +191,80 @@ SETTLE_CYCLES = math.ceil(PLANT_SETTLE_DOWN_S / LOOP_TICK_S)  # 12
 # edge rather than in prose, because it is a property of two files agreeing.
 _SAT_COUNT_CAP = SETTLE_CYCLES + 1                           # 13
 
+# ---------------------------------------------------------------------------
+# SAFETY-48. HOW FAR THE INTEGRATOR MAY STAND AHEAD OF THE COMMAND.
+#
+# ⚠️ THE MISSING CASE, AND IT IS A CASE AND NOT A CONSTANT. The freeze below
+# stops the integrator accumulating, and the comment beside it says what the
+# requirement is: "the INTEGRATOR stop accumulating, not only the command". But
+# `frozen` is computed from ONE signal - `abs(prev_w - actual_w) >
+# saturation_w`, the inverter not tracking - and SLEW-LIMITING NEVER ENTERS IT.
+# When the command hits the step ceiling, the integrator goes on winding at
+# `gain * error` until it reaches `integrator_max_w`.
+#
+# The arithmetic, and it is the whole card:
+#
+#     the integrator moves   gain * error   per cycle
+#     the command moves at most      slew   per cycle
+#     so the integrator outruns the command whenever
+#
+#         |error|  >  slew / gain
+#
+# At the live install's shape (gain 0.6, slew_w 400) that is 667 W. The median
+# grid error at the onset of a recorded episode is 1114 W. This is why
+# SAFETY-39's `slew_w` retune did not fix it: a smaller step makes the
+# threshold LOWER, so the case fires more often, not less.
+#
+# ⚠️ WHAT IS BOUNDED IS THE LEAD, NOT THE INTEGRATOR. Two forms were measured
+# over 16.0 days of the live install's own recorded disturbances
+# (`tools/replay_recorded_loop.py`, and DECISIONS/SAFETY-48 has the table):
+#
+#   (a) reuse the asymmetric freeze on a carried slew flag - "may not wind
+#       further in the direction it is already pushing", exactly as saturation
+#       does. It cuts export 13 % AND RAISES THE BILLED QUANTITY: the worst
+#       quarter-hour average OFFTAKE goes 3739 -> 3935 W and the mean quarter
+#       moves +2.7 W, in five of six plant and tuning variants, and on the
+#       billed quarter it is worse at every plant lag where release/1.0
+#       produces a peak at all (a tie at lag 0, worse at 2.5/5/7.5/10 s)
+#       and at every top-N cut of the quarters.
+#
+#       ⚠️ AND THE MECHANISM IS A REDISTRIBUTION, NOT A WEAKER ANSWER. An
+#       earlier draft of this line said a frozen integrator undershoots by
+#       (1 - gain) "so a large import is answered too weakly". The aggregate
+#       does not show that: form A cuts total import by 5.45 kWh, and paired
+#       tick by tick against release/1.0 it delivers 8.56 kWh LESS offtake
+#       energy on the ticks release/1.0 was importing. What it moves is the
+#       TAIL - within quarters that already net to offtake, the worst of them
+#       gets worse - and the capacity tariff bills the worst quarter and
+#       nothing else. That is the wrong trade here and the reason this is not
+#       the fix that ships.
+#
+#   (b) cap how far the integrator may LEAD the command, one slew step. Export
+#       39.6 -> 34.1 kWh, wasted throughput 4.7 -> 3.2 kWh, sign reversals
+#       2992 -> 2770, worst quarter-hour offtake 3739 -> 3434 W at the fitted
+#       plant lag (⚠️ AND AT NO SHORTER ONE: at every lag <= 5.0 s release/1.0
+#       is already at 3434 W and this changes it by zero - DECISIONS/SAFETY-48
+#       §3a), median recovery 232 -> 199 s. It is what ships.
+#
+# ⚠️ AND THE CAP IS NOT ZERO. `i_w = slewed` is full back-calculation, and this
+# module's own docstring says what that costs: passing `i_w=None` "reduces this
+# function to the exact velocity form it replaced". A zero cap makes `i_w`
+# identically the command on every cycle, which is that same collapse written
+# from the other end - it measures 32.0 kWh, better than (b) by 2 kWh, and it
+# throws away the reason the accumulator was split out at all. One step is the
+# smallest cap that is not that.
+#
+# WHAT THE NUMBER MEANS: the command can cover a one-step lead in ONE cycle, so
+# the worst-case unwind after a reversal is one cycle instead of
+# `integrator_max_w / slew_w` - 12.5 cycles at the live shape, ~60 s at the
+# meter's measured 5.0 s tick.
+#
+# ⚠️ IT IS IN STEPS RATHER THAN IN WATTS FOR SAFETY-39's REASON, WHICH IS THE
+# REASON THIS FILE KEEPS RE-LEARNING. A watt figure is a constant that outlives
+# the `slew_w` it was derived against; expressed in steps it moves with
+# `slew_limit_w()` and therefore with the rail.
+SLEW_LEAD_STEPS = 1
+
 
 @dataclass(frozen=True)
 class Tuning:
@@ -266,6 +340,12 @@ class Decision:
     # the comment at the bound below, and clamp.py.
     i_clamped: bool = False
     clamped: bool = False
+    # SAFETY-40. The alarm's numbers, taken at the clamp so they are one tick's:
+    # the bound the integrator reached, and the command before/after the
+    # rating clamp. `target_w` is this tick's emitted command.
+    i_bound_w: float = 0.0
+    requested_w: float = 0.0
+    clamped_w: float = 0.0
 
 
 def slew_limit_w(tuning: Tuning) -> float:
@@ -489,6 +569,7 @@ def compute(
         # winding, "clamped" is a command that came out over the rating anyway.
         reason = "i-clamped"
     i_w = bounded
+    i_bound_w = bounded if i_clamped else 0.0
     want = i_w
 
     # ⚠️ Maintenance shaping (charge-only, cheap-window floor) used to live
@@ -500,6 +581,7 @@ def compute(
     # An early draft applied a floor after the clamp and let demand escape it.
     target = max(-tuning.max_w, min(tuning.max_w, want))
     clamped = target != want
+    clamped_w = target
     if clamped:
         reason = "clamped"
 
@@ -507,6 +589,83 @@ def compute(
     slewed = max(prev_w - slew, min(prev_w + slew, target))
     if slewed != target:
         reason = "slew-limited"
+        # --- SAFETY-48: the step ceiling reaches the integrator too ---------
+        # ⚠️ INSIDE THIS BRANCH AND NOWHERE ELSE - AND THE REASON IS NOT THE
+        # SATURATION FREEZE. An earlier draft of this comment said that applied
+        # unconditionally the cap "would also pull the integrator toward a
+        # command the SATURATION freeze is pinning", and priced that at 118 of
+        # 256 250 ticks. Both halves were invented, and MUTATION.md habit 22 is
+        # what fell out of it. The 118 had been measured against a DIFFERENT
+        # pair - a band applied after quantisation, at the very end of
+        # `compute()`. On the pair the sentence actually names - this same cap
+        # moved out of this branch to just after `target = slewed` - the two
+        # forms are BIT-IDENTICAL on the shipped configuration: 0 of 256 246
+        # ticks differ over the 16-day recording. They separate only where
+        # `integrator_max_w` is deliberately set ABOVE `max_w`, the one
+        # configuration this file says can reach its `clamped` reason; there
+        # the integrator is meant to run above the rail and an unconditional
+        # cap would drag it back to the command every cycle and make the option
+        # inert. THAT is why the cap stays in the branch, and
+        # `test_telemetry.py` part 4 drives it. (The separable-state COUNT is a
+        # property of whatever grid was swept - 2050 of 257 400 on this card's,
+        # 1220 of 246 064 on the review's, 776 of 40 320 on a third - so the
+        # claim to carry forward is WHERE they separate, not how many.)
+        #
+        # ⚠️ AND THE HALF A READER WILL OTHERWISE ASSUME AWAY: THIS CAP DOES
+        # MOVE A SATURATION-FROZEN INTEGRATOR. It runs BEFORE the freeze block
+        # below and is not gated on `frozen`. Measured over the same recording
+        # at the live shape: of 79 160 frozen ticks the cap changed `i_w` on
+        # 1095 of them, and on 679 of those it moved it FURTHER OUT on the side
+        # it was already on - putting back magnitude the freeze had just let
+        # fall, which is the one direction the freeze's own rule ("may fall,
+        # never rise") exists to forbid. Worst case 2424 W, and the worked tick
+        # is `prev_w -3400 W, grid +4697 W, actual -4144 W, sat_count 2 -> 3`:
+        # the freeze leaves the integrator at -176 W, the slew binds, and the
+        # cap drags it to -2600 W. It never overrides a SAME-CYCLE refusal -
+        # the freeze clipped `moved` on 75 512 ticks and the slew bound on none
+        # of them - but it does not leave the frozen path alone either.
+        #
+        # ⚠️ AND THAT IS WHERE SAFETY-13's SETTLE VALUES WENT. Gating this cap
+        # on `not frozen` puts `test_control.py` part 5 back at release/1.0's
+        # -1190 W exactly; part 4(b)'s -2390 -> -1200 W does NOT come back,
+        # because that one moved for the other reason - the winding BEFORE the
+        # freeze is bounded now. The gate is refused anyway: measured the same
+        # way it leaves a worst observed lead of 4961 W, i.e. no bound at all
+        # on the quantity this card exists to bound. DECISIONS/SAFETY-48 §5
+        # carries the rest of the price.
+        #
+        # ⚠️ WRITTEN ONE-SIDED, AND IT IS **EQUIVALENT** TO THE TWO-SIDED BAND
+        # `max(slewed - cap, min(slewed + cap, i_w))` - MEASURED, NOT REASONED.
+        # An earlier draft of this comment claimed the two-sided spelling was a
+        # bug that would drag a TRAILING integrator up toward the command. That
+        # is false and the sweep said so: `target` is monotone in `i_w`
+        # (`target = clamp(clamp(i_w, +-limit), +-max_w)`) and `slewed` is
+        # `target` pulled toward `prev_w`, so whenever the slew binds, `i_w`
+        # lies on the same side of `slewed` as `target` does and the other
+        # clamp cannot reach. The two spellings agree on **205 920 of 205 920**
+        # cases across four tunings, every sign of `prev_w`, `grid_w`,
+        # `actual_w` and `i_w`, and the `i_w=None` path.
+        #
+        # It stays one-sided because it SAYS which side the lead is on - the
+        # side the command wanted to move and could not - and because a reader
+        # reaching for the band spelling should find the sweep rather than an
+        # argument. ⚠️ The "descending" case is NOT an exception to the rule: a
+        # command falling from +2400 W toward an integrator at +100 W has an
+        # integrator 2300 W ahead of it IN THE DIRECTION OF TRAVEL, and it is
+        # pulled back to one step beyond the emitted command exactly as a
+        # rising one is.
+        #
+        # ⚠️ `i_w` IS CHANGED AND `target` IS NOT. This cycle's command is
+        # already decided; what is bounded is what gets CARRIED. That is also
+        # why the exhaustive `i_w=None` equivalence sweep in test_control.py is
+        # untouched by this card: it compares `(target_w, sat_count, frozen,
+        # reason)`, none of which this moves, and the seeded path re-seeds from
+        # `prev_w` next cycle anyway.
+        _lead_cap = SLEW_LEAD_STEPS * slew
+        if target > slewed:
+            i_w = min(i_w, slewed + _lead_cap)
+        elif target < slewed:
+            i_w = max(i_w, slewed - _lead_cap)
     target = slewed
 
     if frozen:
@@ -589,7 +748,8 @@ def compute(
     target = round(target / step) * step
 
     return Decision(float(target), sat_count, frozen, reason, float(i_w),
-                    i_clamped, clamped)
+                    i_clamped, clamped, float(i_bound_w), float(want),
+                    float(clamped_w))
 
 
 def maintenance_charge_floor(

goodwe_controller/app/custom_formula.py

@@ -125,6 +125,49 @@ units and the market aggregator prints both conventions in one column, so the
 add-on has to be told which one the card is in - and the unit conversion is the
 add-on's job precisely because it is one of the two steps that silently costs a
 factor of 10, 100 or 1000. The other is VAT, which is also the add-on's.
+
+TARIFF-16 - THE SECOND LEG, AND WHY IT IS THIS PARSER AND NOT A SECOND ONE
+==========================================================================
+A Belgian dynamic contract has TWO published lines, not one, and the second is
+what the site is PAID for export:
+
+    Eneco Zon & Wind Dynamisch   0,1 x BELPEX-H - 1,188   c EUR/kWh
+    ENGIE Dynamic                (B x eSpot_15) - A
+    Aspiravi (non-dynamic)       0,07 x Belpex - 2
+
+Same `B x index + A` shape - which is why `price_export_formula` is this
+module's parser with ONE argument moved (`option`), exactly as TARIFF-17 made
+`parse_static_profile()`'s option name a parameter rather than forking the
+period grammar. What differs between the two legs is FOUR numbers and a
+handful of sentences, and all of them are rows of `_LEGS`:
+
+  * its OWN factor - Eneco 0,102 on consumption against 0,100 on injection,
+    Aspiravi 0,07 against ~0,10. NOT the consumption `B` with a sign flip;
+  * a NEGATIVE offset, which `factor`/`offset` already allow and which
+    `price_markup_eur_kwh: float(0,1)` cannot express at all;
+  * `vat_pct: 0` - "Injectietarieven zijn vrijgesteld van btw" - against 6 on
+    consumption, which is a SIX PERCENT ASYMMETRY between the buy leg and the
+    sell leg and is representable only because `vat_pct` is PER SPEC;
+  * a price that goes BELOW ZERO with no floor, in the hours a PV household
+    exports. `implausible_injection()` is the band that accepts that and still
+    refuses an implausible one; `implausible_all_in()` is NOT it, and its
+    docstring says why.
+
+⚠️ AND THE CARD CANNOT ALWAYS GRADE IT. Eneco's injection formula is printed
+with NO price beside it, so on that card there is nothing to reproduce. The
+`card` block is therefore OPTIONAL on this leg and REQUIRED on the other, the
+self-check runs wherever there is a printed estimate, and validate.py says at
+startup when a leg is ungraded. Inventing an estimate to grade against would
+be grading arithmetic against itself, which is the defect MUTATION.md habit 4
+is about; TARIFF-15 demonstrated two tariffs end to end rather than three for
+the same reason.
+
+⚠️ NOTHING TRADES ON THIS TODAY, AND SAYING SO IS PART OF SHIPPING IT.
+`arbitrage.py` does not read `export_price_eur_kwh` at all - its own comment
+says so, citing §9.3's near-zero Belgian injection price - and both hours it
+compares are all-in CONSUMPTION prices. So this is not a wrong-trade defect
+and must not be described as one. What it changes is what an operator is told,
+and what a future export-aware strategy would rest on.
 """
 
 import json
@@ -132,6 +175,8 @@ import math
 from dataclasses import dataclass
 from datetime import date, datetime, timezone
 
+from . import messages
+
 
 class FormulaInvalid(Exception):
     """`price_formula` cannot be used. Raised by the parser, refused by
@@ -156,7 +201,7 @@ RESOLUTIONS: tuple = ("hourly", "quarter_hourly")
 # index id -> the human name of the series it refers to. One entry today; a
 # second index is a new row here plus a fetch path, not a new grammar.
 INDEXES: dict = {
-    "epex_be": "EPEX BE day-ahead, EUR/MWh",
+    "epex_be": "Belgian day-ahead price, EUR/MWh",
 }
 
 # ⚠️ 0.01 IN THE CARD'S OWN UNITS, WHICH IS THE LAST DIGIT BOTH REAL CARDS
@@ -183,6 +228,91 @@ _CARD_KEYS = ("month", "index_eur_per_mwh", "expect_incl_vat")
 _TOP_KEYS = ("index", "resolution", "factor", "offset", "units", "vat_pct",
              "card")
 
+# --------------------------------------------------------------------------- #
+# TARIFF-16 - the SECOND leg, and the one parameter that carries it
+# --------------------------------------------------------------------------- #
+
+EXPORT_FORMULA_OPTION = "price_export_formula"
+
+# ⚠️ THE PASS-THROUGH FRACTION, WHICH IS WHY THE NEXT TWO BOUNDS CAN BE
+# INDEX-FREE. One EUR/MWh IS 0.001 EUR/kWh, so `factor x UNITS[units] / 0.001`
+# is the dimensionless share of the wholesale price the contract passes
+# through - 1.00 for Eneco's injection leg (0,100 c EUR/kWh per EUR/MWh), 0.70
+# for Aspiravi's (0,07). A coefficient typed a hundred times too small or too
+# large moves this by a hundred, whatever the index and whatever the sign of
+# the price.
+EUR_KWH_PER_EUR_MWH = 0.001
+
+# The two plausibility bounds for an INJECTION leg. ⚠️ NEITHER LOOKS AT THE
+# SIGN OF THE PRICE, AND THAT IS THE WHOLE POINT - see
+# `implausible_injection()`.
+PASSTHROUGH_LO = 0.10       # 10% of the wholesale price
+PASSTHROUGH_HI = 10.0       # 1000% of it
+INJECTION_OFFSET_MAX_EUR_KWH = 0.20
+
+
+@dataclass(frozen=True)
+class _Leg:
+    """What ONE option's coefficients price, as sentences its refusals read.
+
+    ⚠️ TARIFF-16 MADE `option` A PARAMETER RATHER THAN FORKING THE PARSER,
+    exactly as TARIFF-17 made `option`/`means` parameters of
+    `parse_static_profile()` rather than forking the period grammar. A second
+    copy of this parser would be a second `_finite()`, a second unknown-key
+    rule, a second unit table and a second `to_resolution()` - and the two
+    would diverge first on the 23- and 25-hour days, where nobody looks.
+    Everything that differs between the consumption leg and the injection leg
+    is a STRING in this table; the arithmetic, the enumerations, the card
+    comparison and the resolution rule are ONE implementation with one set of
+    checks over it.
+    """
+
+    option: str
+    what: str            # "consumption" / "injection", for a sentence
+    example: str         # a VALID blob for this leg, in the JSON-error hint
+    when: str            # when this option is read at all
+    flat: str            # where a FLAT price of this kind already lives
+    zero_factor: str     # what a factor of 0 actually costs on this leg
+    neg_factor: str      # why a negative FACTOR is wrong on this leg
+    card_required: bool
+    card_note: str       # why it is required, or what is lost without it
+    card_causes: str     # the leg-specific tail of `card_refusal()`
+
+
+_LEGS = {
+    "price_formula": _Leg(
+        option="price_formula",
+        what="consumption",
+        example=('{"index":"epex_be","resolution":"hourly","factor":0.102,'
+                 '"offset":1.00,"units":"c_eur_per_kwh","vat_pct":6,'
+                 '"card":{"month":"2026-09","index_eur_per_mwh":133.9905,'
+                 '"expect_incl_vat":15.55}}'),
+        when="Leave it empty unless “Dynamic price source” is 'custom_formula'.",
+        zero_factor=" and trading never finds a price difference",
+        flat="use “Fixed or day/night tariff” (static_profile) instead",
+        neg_factor="Put the minus sign on the offset, not on the factor",
+        card_required=True,
+        card_note="The add-on needs it to check your two numbers",
+        card_causes=("the units, the VAT, and that network charges are not "
+                     "in the offset"),
+    ),
+    EXPORT_FORMULA_OPTION: _Leg(
+        option=EXPORT_FORMULA_OPTION,
+        what="injection",
+        example=('{"index":"epex_be","resolution":"hourly","factor":0.1,'
+                 '"offset":-1.188,"units":"c_eur_per_kwh","vat_pct":0}'),
+        when="Fill it in only if your injection price follows the market.",
+        zero_factor="",
+        flat="use “Injection price” (export_price_eur_kwh) instead",
+        neg_factor="Put the minus sign on the offset, not on the factor",
+        card_required=False,
+        card_note=("It is optional here. Without it the add-on only checks "
+                   "the size of your two numbers"),
+        card_causes="the units, and that the VAT is 0 for injection",
+    ),
+}
+
+
 
 @dataclass(frozen=True)
 class FormulaSpec:
@@ -199,14 +329,44 @@ class FormulaSpec:
     offset: float
     units: str
     vat_pct: float
-    card_month: str                 # "YYYY-MM", as the card is dated
-    card_index_eur_per_mwh: float
-    card_expect_incl_vat: float     # in `units`, as the card prints it
+    card_month: str = ""            # "YYYY-MM", as the card is dated
+    card_index_eur_per_mwh: float = None
+    card_expect_incl_vat: float = None   # in `units`, as the card prints it
+    # TARIFF-16. Which OPTION this spec was read from, so a refusal, a log line
+    # and `card_graded` name the leg the operator actually typed.
+    option: str = "price_formula"
 
     @property
     def unit_to_eur_kwh(self) -> float:
         return UNITS[self.units]
 
+    @property
+    def card_graded(self) -> bool:
+        """Is there a printed estimate to grade these coefficients against?
+
+        ⚠️ FALSE IS A REAL, SHIPPED STATE ON THE INJECTION LEG and is reported
+        rather than defaulted: Eneco's injection formula is printed with no
+        price beside it. Never False on `price_formula`, where `_card()`
+        refuses an absent block.
+        """
+        return self.card_expect_incl_vat is not None
+
+    @property
+    def passthrough(self) -> float:
+        """The dimensionless share of the wholesale price this passes through.
+
+        `factor x UNITS[units] / 0.001`. 1.00 for Eneco's injection leg, 0.70
+        for Aspiravi's. ⚠️ INDEX-FREE AND SIGN-FREE, which is what lets
+        `implausible_injection()` bound a leg whose price legitimately goes
+        below zero.
+        """
+        return self.factor * self.unit_to_eur_kwh / EUR_KWH_PER_EUR_MWH
+
+    @property
+    def offset_eur_kwh(self) -> float:
+        """The offset in EUR/kWh, whatever units the card printed it in."""
+        return self.offset * self.unit_to_eur_kwh
+
 
 # --------------------------------------------------------------------------- #
 # The arithmetic. Two functions, and the SECOND one is the contract.
@@ -241,7 +401,18 @@ def card_discrepancy(spec: FormulaSpec) -> float:
     In the card's units, signed: positive means the formula computes MORE than
     the card prints, which is the direction an `offset` carrying network
     charges moves it.
+
+    ⚠️ RAISES ON A SPEC WITH NO CARD RATHER THAN RETURNING 0.0 (TARIFF-16). An
+    ungraded injection leg has no printed estimate, and a discrepancy of zero
+    is exactly what "the coefficients reproduce the card" looks like - so a
+    silent zero here would report the strongest possible result for the one
+    state in which nothing was compared at all.
     """
+    if not spec.card_graded:
+        raise FormulaInvalid(
+            f"{spec.option} has no card block, so there is no printed "
+            f"estimate to measure a discrepancy against. Ask "
+            f"`spec.card_graded` before calling this.")
     return in_card_units(spec, spec.card_index_eur_per_mwh) \
         - spec.card_expect_incl_vat
 
@@ -250,7 +421,7 @@ def card_discrepancy(spec: FormulaSpec) -> float:
 # Reading the option
 # --------------------------------------------------------------------------- #
 
-def _finite(value, field: str) -> float:
+def _finite(value, field: str, option: str = "price_formula") -> float:
     """A real, finite number - or a refusal naming the field.
 
     ⚠️ SAME CLASS AS `_validate_raw()`'s NaN RULE, one layer earlier. A NaN
@@ -260,51 +431,54 @@ def _finite(value, field: str) -> float:
     """
     if isinstance(value, bool) or not isinstance(value, (int, float)):
         raise FormulaInvalid(
-            f"price_formula.{field} is {value!r}, which is not a number. "
-            f"Write the coefficient as a bare JSON number - 0.102, not "
-            f"\"0.102\" and not an expression: this provider takes FIXED "
-            f"coefficients and evaluates nothing.")
+            f"{option}.{field} is {value!r}, which is not a number. Write a "
+            f"plain number, for example 0.102.")
     if not math.isfinite(float(value)):
         raise FormulaInvalid(
-            f"price_formula.{field} is {value!r}, which is not finite. A NaN "
-            f"or an infinity here makes every price NaN, every price "
-            f"comparison False, and an arbitrage strategy that never fires "
-            f"while reporting that it is armed.")
+            f"{option}.{field} is {value!r}, which is not finite. Write a "
+            f"plain number, for example 0.102.")
     return float(value)
 
 
-def _card(raw) -> tuple:
-    """The `card` block: the estimate the coefficients are graded against."""
+def _card(raw, leg: _Leg = None) -> tuple:
+    """The `card` block: the estimate the coefficients are graded against.
+
+    ⚠️ REQUIRED ON THE CONSUMPTION LEG AND OPTIONAL ON THE INJECTION ONE, and
+    the asymmetry is a fact about the CARDS rather than a relaxed rule. See
+    `_LEGS[EXPORT_FORMULA_OPTION].card_note`: Eneco's injection formula is
+    printed with no price beside it, so on that card there is nothing to grade
+    against. `("", None, None)` is the ungraded answer and
+    `FormulaSpec.card_graded` is how every caller asks.
+    """
+    if leg is None:
+        leg = _LEGS["price_formula"]
     if raw is None:
+        if not leg.card_required:
+            return ("", None, None)
         raise FormulaInvalid(
-            "price_formula has no \"card\" block, and it is REQUIRED. It is "
-            "the only thing that can tell a correct pair of coefficients from "
-            "a plausible-looking wrong one: the add-on recomputes your "
-            "supplier's own printed example from the numbers you typed and "
-            "refuses to start if it does not come out. Copy the three figures "
-            "off the same tariff card as the coefficients: "
+            f"{leg.option} has no \"card\" block. {leg.card_note}. Copy "
+            "the three figures from your tariff card, for example "
             "{\"month\": \"2026-09\", \"index_eur_per_mwh\": 133.9905, "
             "\"expect_incl_vat\": 15.55}.")
     if not isinstance(raw, dict):
         raise FormulaInvalid(
-            f"price_formula.card is {type(raw).__name__}, not an object with "
+            f"{leg.option}.card is {type(raw).__name__}, not an object with "
             f"{', '.join(_CARD_KEYS)}.")
     unknown = sorted(set(raw) - set(_CARD_KEYS))
     if unknown:
         raise FormulaInvalid(
-            f"price_formula.card has no field(s) {unknown}. The fields it "
-            f"takes are {list(_CARD_KEYS)}; a key that is merely ignored is a "
-            f"number the operator believes took effect.")
+            f"{leg.option}.card has unknown field(s) {unknown}. It takes "
+            f"only {list(_CARD_KEYS)}.")
     month = str(raw.get("month", "") or "").strip()
     if not _month_date(month):
         raise FormulaInvalid(
-            f"price_formula.card.month is {raw.get('month')!r}; write the "
-            f"month the card is dated as \"YYYY-MM\", e.g. \"2026-09\". It is "
-            f"not used in any price - it is what lets the add-on tell you "
-            f"your card has gone stale.")
+            f"{leg.option}.card.month is {raw.get('month')!r}. Write the "
+            f"month of the card as \"YYYY-MM\", for example \"2026-09\".")
     return (month,
-            _finite(raw.get("index_eur_per_mwh"), "card.index_eur_per_mwh"),
-            _finite(raw.get("expect_incl_vat"), "card.expect_incl_vat"))
+            _finite(raw.get("index_eur_per_mwh"), "card.index_eur_per_mwh",
+                    leg.option),
+            _finite(raw.get("expect_incl_vat"), "card.expect_incl_vat",
+                    leg.option))
 
 
 def _month_date(month: str):
@@ -316,9 +490,16 @@ def _month_date(month: str):
         return None
 
 
-def parse_price_formula(value):
+def parse_price_formula(value, *, option: str = "price_formula"):
     """`price_formula` -> a `FormulaSpec`, or None when unset.
 
+    ⚠️ `option` IS TARIFF-16'S WHOLE REUSE, and it is TARIFF-17's move. It
+    selects a row of `_LEGS` and nothing else: the enumerations, the
+    arithmetic, `to_resolution()`, the unknown-key rule and the card
+    comparison are shared, and every pre-existing call site - which passes no
+    `option` at all - lands on the consumption row and reads byte-identical
+    sentences. `parse_export_formula()` is a two-line wrapper, not a fork.
+
     Accepts what the option can actually arrive as, exactly as
     `parse_static_profile()` does:
 
@@ -335,6 +516,7 @@ def parse_price_formula(value):
     fetch - go through this one function, so there is no route to a price that
     has not been graded against the card.
     """
+    leg = _LEGS[option]
     if value is None:
         return None
     if isinstance(value, str):
@@ -345,16 +527,11 @@ def parse_price_formula(value):
             value = json.loads(text)
         except ValueError as e:
             raise FormulaInvalid(
-                f"price_formula is not valid JSON ({e}). It is a JSON object "
-                f"on one line, e.g.\n"
-                f'  {{"index":"epex_be","resolution":"hourly","factor":0.102,'
-                f'"offset":1.00,"units":"c_eur_per_kwh","vat_pct":6,'
-                f'"card":{{"month":"2026-09","index_eur_per_mwh":133.9905,'
-                f'"expect_incl_vat":15.55}}}}\n'
-                f"Leave it empty unless price_provider is 'custom_formula'.")
+                f"{messages.not_valid(option, e)}. Copy the example from the "
+                f"documentation. {leg.when}")
     if not isinstance(value, dict):
         raise FormulaInvalid(
-            f"price_formula is {type(value).__name__}, not a JSON object with "
+            f"{option} is {type(value).__name__}, not a JSON object with "
             f"{', '.join(_TOP_KEYS)}.")
 
     # ⚠️ AN UNKNOWN KEY IS REFUSED, NOT IGNORED, AND THIS IS THE HALF THAT
@@ -366,34 +543,21 @@ def parse_price_formula(value):
     unknown = sorted(set(value) - set(_TOP_KEYS))
     if unknown:
         raise FormulaInvalid(
-            f"price_formula has no field(s) {unknown}. The fields it takes "
-            f"are {list(_TOP_KEYS)}. ⚠️ There is deliberately NO field that "
-            f"takes an expression: this provider multiplies and adds two "
-            f"FIXED coefficients and evaluates nothing, because two "
-            f"coefficients can be graded against your card's printed price "
-            f"and an arbitrary expression cannot be graded against anything. "
-            f"If your contract needs a shape this cannot express, it needs a "
-            f"new named field here - say which shape.")
+            f"{option} has unknown field(s) {unknown}. It takes only "
+            f"{list(_TOP_KEYS)}.")
 
     index = str(value.get("index", "") or "").strip()
     if index not in INDEXES:
         raise FormulaInvalid(
-            f"price_formula.index is {value.get('index')!r}. The reference "
-            f"series this add-on can fetch are "
-            f"{', '.join(f'{k!r} ({v})' for k, v in sorted(INDEXES.items()))}. "
-            f"If your card names a different index, the add-on cannot get it "
-            f"and guessing which series your supplier meant would price your "
-            f"battery against the wrong curve.")
+            f"{option}.index is {value.get('index')!r}. The add-on can only "
+            f"fetch "
+            f"{', '.join(f'{k!r} ({v})' for k, v in sorted(INDEXES.items()))}.")
 
     resolution = str(value.get("resolution", "") or "").strip()
     if resolution not in RESOLUTIONS:
         raise FormulaInvalid(
-            f"price_formula.resolution is {value.get('resolution')!r}; it "
-            f"must be one of {list(RESOLUTIONS)}. Belgium has been on a "
-            f"15-minute MTU since 2025-10-01 and the feed publishes 96 points "
-            f"a day; a contract written against the HOURLY series is priced "
-            f"on the mean of each hour's quarters. Which one your contract "
-            f"uses is on your card and cannot be inferred from the feed.")
+            f"{option}.resolution is {value.get('resolution')!r}. Choose one "
+            f"of {list(RESOLUTIONS)}, as your tariff card says.")
 
     # ⚠️ `units` IS REQUIRED AND HAS NO DEFAULT. A default here would be the
     # factor-1000 class with a friendly face: the add-on would silently assume
@@ -402,16 +566,12 @@ def parse_price_formula(value):
     units = str(value.get("units", "") or "").strip()
     if units not in UNITS:
         raise FormulaInvalid(
-            f"price_formula.units is {value.get('units')!r} and is REQUIRED - "
-            f"there is no default, on purpose. It must be one of "
-            f"{sorted(UNITS)}. Your card prints the formula in ONE of these "
-            f"and two suppliers use two different conventions for the same "
-            f"shape, so assuming one would be a factor of 100 or 1000 on "
-            f"every hour with nothing able to notice.")
+            f"{option}.units is {value.get('units')!r}. Choose one of "
+            f"{sorted(UNITS)}, as printed beside the formula on your card.")
 
-    factor = _finite(value.get("factor"), "factor")
-    offset = _finite(value.get("offset"), "offset")
-    vat_pct = _finite(value.get("vat_pct"), "vat_pct")
+    factor = _finite(value.get("factor"), "factor", option)
+    offset = _finite(value.get("offset"), "offset", option)
+    vat_pct = _finite(value.get("vat_pct"), "vat_pct", option)
 
     # ⚠️ ZERO IS NOT "NO INDEXATION", IT IS A FIXED TARIFF WEARING A DYNAMIC
     # ONE'S CLOTHES. Every hour comes out at the same price, so every spread is
@@ -421,15 +581,8 @@ def parse_price_formula(value):
     # the operator at it rather than let them build it by accident.
     if factor == 0.0:
         raise FormulaInvalid(
-            "price_formula.factor is 0, so the index would not enter the "
-            "price at all: every hour of every day comes out at "
-            f"{offset:g} x (1 + {vat_pct:g}/100), every spread is exactly 0, "
-            "and arbitrage can never clear any threshold - a strategy that "
-            "silently never fires rather than one that is off. If your tariff "
-            "really is one flat price, that is `static_profile` with a single "
-            "period covering 00:00-24:00 on all days and price_provider "
-            "'off'; the add-on then says so at startup instead of leaving you "
-            "to find out from a year of unchanged bills.")
+            f"{option}.factor is 0, so every hour gets the same {leg.what} "
+            f"price{leg.zero_factor}. For one flat price, {leg.flat}.")
 
     # ⚠️ A NEGATIVE FACTOR INVERTS THE MARKET, and the direction is the danger:
     # the dearest hour becomes the cheapest one, so the battery is told to
@@ -437,74 +590,102 @@ def parse_price_formula(value):
     # mispriced site, it is a site actively trading against itself.
     if factor < 0.0:
         raise FormulaInvalid(
-            f"price_formula.factor is {factor:g}, which is NEGATIVE. That "
-            f"inverts the market: the dearest hour of the day comes out as "
-            f"the cheapest one, so the battery would charge at the evening "
-            f"peak and discharge at 03:00 - trading against itself on every "
-            f"cycle. No consumption tariff is indexed negatively; if your "
-            f"card shows a minus sign it is on the OFFSET (`A`), which is "
-            f"allowed here and common on injection.")
+            f"{option}.factor is {factor:g}, which turns the market upside "
+            f"down. {leg.neg_factor}.")
 
     # ⚠️ 0 IS LEGITIMATE AND MUST STAY SO: injection is VAT-exempt in Belgium,
     # and some cards are already quoted VAT-inclusive. The bound exists for the
     # 106 / 1.06 / 6 confusion, not to make VAT compulsory.
     if not 0.0 <= vat_pct <= 30.0:
         raise FormulaInvalid(
-            f"price_formula.vat_pct is {vat_pct:g} and must be between 0 and "
-            f"30. It is a PERCENTAGE, so Belgian residential electricity is "
-            f"6, not 0.06 and not 106. Zero is legitimate and is not refused: "
-            f"injection is VAT-exempt, and a card that already quotes "
-            f"VAT-inclusive coefficients needs no second multiplication.")
+            f"{option}.vat_pct is {vat_pct:g}. Write a percentage between 0 "
+            f"and 30, for example 6.")
 
-    month, card_index, card_expect = _card(value.get("card"))
+    month, card_index, card_expect = _card(value.get("card"), leg)
     spec = FormulaSpec(index=index, resolution=resolution, factor=factor,
                        offset=offset, units=units, vat_pct=vat_pct,
                        card_month=month, card_index_eur_per_mwh=card_index,
-                       card_expect_incl_vat=card_expect)
+                       card_expect_incl_vat=card_expect, option=option)
 
-    delta = card_discrepancy(spec)
-    if abs(delta) > CARD_TOLERANCE:
-        raise FormulaInvalid(card_refusal(spec, delta))
+    # ⚠️ THE CARD SELF-CHECK STILL RUNS WHEREVER THERE IS A CARD TO RUN IT
+    # AGAINST, on either leg, with the same tolerance. What TARIFF-16 adds is
+    # the honest answer for the leg where the card prints no estimate: NOT a
+    # weakened comparison and NOT an estimate computed here, but two bounds on
+    # the COEFFICIENTS that need no printed price - see
+    # `implausible_injection()` - and a startup line saying the leg is
+    # ungraded.
+    if spec.card_graded:
+        delta = card_discrepancy(spec)
+        if abs(delta) > CARD_TOLERANCE:
+            raise FormulaInvalid(card_refusal(spec, delta))
+    if option == EXPORT_FORMULA_OPTION:
+        band = implausible_injection(spec)
+        if band:
+            raise FormulaInvalid(band)
     return spec
 
 
+def parse_export_formula(value):
+    """`price_export_formula` -> the INJECTION leg's `FormulaSpec`, or None.
+
+    TARIFF-16. THE DEFECT THIS EXISTS TO CLOSE: `price.py` modelled injection
+    as ONE scalar, and the market publishes a line with four properties a
+    scalar cannot hold. Verbatim off the cards:
+
+        Eneco Zon & Wind Dynamisch   0,1 x BELPEX-H - 1,188   c EUR/kWh
+            "Het injectietarief is dynamisch en kan per uur wijzigen"
+            - identical on the January and the September 2026 cards
+        ENGIE Dynamic                (B x eSpot_15) - A       c EUR/kWh
+        Aspiravi (non-dynamic)       0,07 x Belpex - 2
+
+      1. ITS OWN FACTOR. Eneco uses 0,102 on consumption and 0,100 on
+         injection; Aspiravi 0,07 against ~0,10 on its consumption leg. It is
+         NOT the consumption `B` with a sign flip.
+      2. A NEGATIVE OFFSET - `- 1,188`, `- 2`. Note that
+         `price_markup_eur_kwh: float(0,1)` cannot express a negative markup
+         at all, so the offset has no home on the consumption side either.
+      3. VAT-EXEMPT. "Injectietarieven zijn vrijgesteld van btw", while
+         consumption is at 6% - a SIX PERCENT ASYMMETRY between the buy leg
+         and the sell leg, which a single scalar cannot even state.
+      4. IT GOES NEGATIVE, WITH NO FLOOR. Eneco's injection price is negative
+         for any BELPEX-H below 11,88 EUR/MWh, and a PV household exports
+         precisely in the hours most likely to be negative. You can be charged
+         to export.
+
+    ⚠️ AND WHAT THIS DOES **NOT** AFFECT TODAY, SAID HERE SO NOBODY READS THE
+    ABOVE AS A TRADING BUG. `arbitrage.py` does not read
+    `export_price_eur_kwh` at all - its own comment says so, and gives §9.3's
+    near-zero Belgian injection price as the reason the economically sound
+    trade on this market is charge-cheap-to-displace-expensive-IMPORT. Both
+    hours it compares are all-in CONSUMPTION prices. So no trade the add-on
+    takes today is decided by this number, and this card is not a correction
+    of a wrong trade. What it changes is what an operator is told, and what
+    any future export-aware strategy would rest on: OPT-06 and any export
+    logic would otherwise inherit a scalar that cannot represent the market,
+    and the 6% VAT asymmetry would be invisible in the arithmetic.
+
+    ⚠️ THE SCALAR IS NOT REPLACED. `export_price_eur_kwh()` is untouched and
+    still answers for every site with a flat injection price, which is every
+    site that exists today; this option ships "". That is `price.py`'s own
+    prediction coming true rather than a new design - "when it does land, an
+    injection curve gets a `PriceProvider` of its own and this scalar becomes
+    its FIXED-product default; the seam is already the right shape for that."
+    """
+    return parse_price_formula(value, option=EXPORT_FORMULA_OPTION)
+
+
 def card_refusal(spec: FormulaSpec, delta: float) -> str:
     """The sentence an operator reads when their formula misses its own card.
 
-    ⚠️ IT NAMES THE DISCREPANCY AND THE SIX WAYS IT HAPPENS. "Invalid
-    configuration" would be true and useless: every one of these errors looks
-    exactly like a working tariff from the status page, which is why the check
-    exists at all.
+    It names both numbers and what to check. The usual causes are in DOCS.md,
+    because each of these errors looks like a working tariff on the status page.
     """
     got = in_card_units(spec, spec.card_index_eur_per_mwh)
-    ratio = (got / spec.card_expect_incl_vat
-             if spec.card_expect_incl_vat else float("inf"))
+    leg = _LEGS[spec.option]
     return (
-        f"price_formula does not reproduce its own card, so the add-on will "
-        f"NOT start on it. Your contract's arithmetic is "
-        f"price = (factor x index_eur_per_mwh + offset) x (1 + vat_pct/100); "
-        f"on the card's own index that is "
-        f"({spec.factor:g} x {spec.card_index_eur_per_mwh:g} + "
-        f"{spec.offset:g}) x (1 + {spec.vat_pct:g}/100) = {got:.4f} "
-        f"{spec.units}, but card.expect_incl_vat says "
-        f"{spec.card_expect_incl_vat:g} - OUT BY {delta:+.4f} {spec.units} "
-        f"(ratio {ratio:.4g}; the tolerance is {CARD_TOLERANCE}, which is the "
-        f"last digit a card prints). One of the two sides is wrong and the "
-        f"add-on cannot tell which, so it refuses rather than price a battery "
-        f"on it. The usual causes, in the order they happen: the coefficients "
-        f"and the expected price are in DIFFERENT units (ratio 10, 100 or "
-        f"1000 - `units` must be the one the formula line is printed in); VAT "
-        f"left out or applied twice (ratio 1.06 or 1/1.06); a transposed "
-        f"digit; the two sides copied off DIFFERENT cards or different "
-        f"months; or - the expensive one - network charges, levies or excise "
-        f"folded into `offset`. ⚠️ THEY DO NOT BELONG THERE: a Belgian card's "
-        f"Tariefformule line is the ENERGY component alone (Eneco tabulates "
-        f"network tariffs and levies separately; ENGIE says in so many words "
-        f"that the formula excludes network, distribution, transport, levies "
-        f"and excise), the add-on adds price_taxes_eur_kwh on top of it, and "
-        f"folding ~12 c EUR/kWh of network charge into `offset` bills you for "
-        f"it twice. That is the error this check exists to catch, and it is "
-        f"why it cannot be switched off.")
+        f"{spec.option} gives {got:.4f} "
+        f"{messages.UNIT_WORDS.get(spec.units, spec.units)}, the card says "
+        f"{spec.card_expect_incl_vat:g}. Check {leg.card_causes}.")
 
 
 # --------------------------------------------------------------------------- #
@@ -520,13 +701,16 @@ def implausible_all_in(spec: FormulaSpec, taxes_eur_kwh: float):
 
     ⚠️ THE LOW END IS GRADED ON THE ENERGY COMPONENT AND THE HIGH END ON THE
     ALL-IN FIGURE, AND THAT ASYMMETRY IS THE CHECK RATHER THAN AN OVERSIGHT.
-    `price_taxes_eur_kwh` ships at 0.06, which is three times the low bound -
-    so a card read a HUNDRED times too small comes out at 0.0016 EUR/kWh of
-    energy, is carried over the floor by the flat tax addend alone, and passes
-    a band applied to the all-in total. The hundredfold error is precisely
-    what this exists to catch, so the floor is applied where it can still see
-    it. The ceiling is applied to the all-in figure because that is the number
-    the site is really billed at, and taxes only push it up.
+    `price_taxes_eur_kwh` ships at 0.11736 (TARIFF-18; it was 0.06 before, and
+    the argument was already decisive at that figure), which is nearly SIX
+    times the low bound - so a card read a HUNDRED times too small comes out at
+    0.0016 EUR/kWh of energy, is carried over the floor by the flat tax addend
+    alone, and passes a band applied to the all-in total. The hundredfold error
+    is precisely what this exists to catch, so the floor is applied where it
+    can still see it. ⚠️ Raising the default made this trap WIDER, not
+    narrower: the addend that does the carrying got bigger. The ceiling is
+    applied to the all-in figure because that is the number the site is really
+    billed at, and taxes only push it up.
 
     ⚠️ AND THE LIMIT, WITH THE CLAIM. This grades the CARD'S OWN POINT - one
     price, at the monthly index the card assumed - and not every hour of every
@@ -536,26 +720,89 @@ def implausible_all_in(spec: FormulaSpec, taxes_eur_kwh: float):
     fetched series. What it catches is a formula whose whole LEVEL is wrong,
     which is the factor-of-1000 class arriving from the end
     `MAX_PLAUSIBLE_EUR_KWH` does not bound.
+
+    ⚠️ AND IT IS THE CONSUMPTION LEG'S BAND ONLY - TARIFF-16 DELIBERATELY DID
+    NOT POINT IT AT THE INJECTION LEG. Two reasons, and the second is an
+    acceptance criterion rather than a preference:
+
+      * it adds `taxes_eur_kwh`, and `price_taxes_eur_kwh` is a CONSUMPTION
+        component. Nothing is added to what a site is PAID for export, so the
+        `all_in` half would be adding a number the injection leg never carries;
+      * its floor is `energy >= 0.02 EUR/kWh`, and a REAL Eneco injection price
+        is negative for any BELPEX-H below 11,88 EUR/MWh - the hours a PV
+        household actually exports in. Applied to injection this floor would
+        refuse the market, and refuse it hardest in the hours where knowing the
+        number matters most. `implausible_injection()` is the injection band
+        and it is deliberately NOT this function with a lower floor.
     """
     energy = price_eur_kwh(spec, spec.card_index_eur_per_mwh)
     all_in = energy + float(taxes_eur_kwh)
     if energy >= PLAUSIBLE_LO_EUR_KWH and all_in <= PLAUSIBLE_HI_EUR_KWH:
         return None
     return (
-        f"price_formula's own card works out at {energy:.5f} EUR/kWh of "
-        f"energy ({spec.card_expect_incl_vat:g} {spec.units} as the card "
-        f"prints it) and {all_in:.5f} EUR/kWh all-in once "
-        f"price_taxes_eur_kwh is added, which is outside the plausible band "
-        f"{PLAUSIBLE_LO_EUR_KWH}-{PLAUSIBLE_HI_EUR_KWH} EUR/kWh for a Belgian "
-        f"retail tariff. The card self-check passed, so the coefficients and "
-        f"the printed price AGREE - they simply agree on a number no Belgian "
-        f"bill carries, which is what a whole card read in the wrong units "
-        f"looks like (a factor of 10, 100 or 1000 applied to BOTH sides at "
-        f"once cancels out of that check and cannot cancel out of this one). "
-        f"Check `units` against the unit printed beside your formula. "
-        f"⚠️ This bounds the CARD'S OWN POINT, not every hour: a live hour may "
-        f"legitimately fall outside the band, and a negative day-ahead hour - "
-        f"the best charging opportunity of the year - is never refused.")
+        f"{spec.option} gives {energy:.5f} EUR/kWh for energy and "
+        f"{all_in:.5f} EUR/kWh with “Distribution, levies and VAT” "
+        f"(price_taxes_eur_kwh), outside the plausible band of "
+        f"{PLAUSIBLE_LO_EUR_KWH}-{PLAUSIBLE_HI_EUR_KWH} EUR/kWh. Check \"units\" against the unit beside your formula.")
+
+
+def implausible_injection(spec: FormulaSpec):
+    """The INJECTION leg's plausibility band. Returns a refusal or None.
+
+    ⚠️ A NEGATIVE INJECTION PRICE IS ACCEPTED, NOT REFUSED, AND NEITHER RUNG
+    BELOW LOOKS AT THE SIGN OR THE LEVEL OF A PRICE. Eneco's published line
+    `0,1 x BELPEX-H - 1,188` is negative for any BELPEX-H under 11,88 EUR/MWh;
+    those are the midday hours a PV household exports in, so a band with a
+    floor above zero - which is what `implausible_all_in()` has, for the
+    consumption leg's own good reasons - would refuse the real market and
+    would hide it in exactly the hours it costs money. You CAN be charged to
+    export. The add-on says so rather than declining to represent it.
+
+    THE PROBLEM THAT LEAVES, STATED BEFORE THE SOLUTION. The consumption
+    floor was not decoration: it is what catches a whole card read a hundred
+    times too small, the one unit error the card self-check cannot see because
+    it cancels out of a comparison between the two sides. A band that spans
+    zero cannot catch it - 0.00132 EUR/kWh is inside any interval that
+    contains -0.03. So the bound moves OFF the price and ONTO the
+    coefficients, where it is index-free and sign-free:
+
+      * PASS-THROUGH. `factor x UNITS[units] / 0.001` is the dimensionless
+        share of the wholesale price the contract passes through, because one
+        EUR/MWh IS 0.001 EUR/kWh. Eneco's injection leg is 1.00 and Aspiravi's
+        is 0.70. A factor typed 100x too small reads 0.01 and 100x too large
+        reads 100, whatever the index and whatever the sign of the result.
+      * OFFSET MAGNITUDE. Eneco's is 1,188 c EUR/kWh = 0.01188 EUR/kWh and
+        Aspiravi's is 2 c = 0.02. A hundredfold error is 1.188 EUR/kWh, which
+        is not an injection tariff in any direction. The bound is on the
+        ABSOLUTE value, so a negative offset of a believable size passes and
+        that is the normal case on this leg.
+
+    ⚠️ TWO RUNGS THAT CAN BOTH ANSWER ONE STIMULUS, SO THEY ARE GRADED ON
+    THEIR REASONS AND MUTATED TOGETHER (MUTATION.md, TEST-16). A whole card
+    read 100x too large trips both. The fixtures in test_price.py 17d are
+    built so that each rung is the ONLY one that fires on its own stimulus.
+
+    ⚠️ AND WHAT THIS CANNOT SEE, WITH THE CLAIM (habit 13). It bounds the
+    SHAPE of the coefficients, never their truth: a contract really written
+    against a different index, or last year's coefficients, passes both rungs
+    and reproduces any card typed beside them. Where a card DOES print an
+    estimate the self-check grades the pair against it; where it does not -
+    which is Eneco's injection line - these two bounds are the whole of what
+    is mechanised, and validate.py says so at startup.
+    """
+    if not PASSTHROUGH_LO <= spec.passthrough <= PASSTHROUGH_HI:
+        return (
+            f"{spec.option}.factor passes through {spec.passthrough:.4g}x the "
+            f"market price, outside {PASSTHROUGH_LO}-{PASSTHROUGH_HI}x. Check "
+            f"\"units\" ({spec.units!r}) against the unit beside your "
+            f"formula.")
+    if abs(spec.offset_eur_kwh) > INJECTION_OFFSET_MAX_EUR_KWH:
+        return (
+            f"{spec.option}.offset is {spec.offset:g} {spec.units}, which is "
+            f"{spec.offset_eur_kwh:+.5f} EUR/kWh and larger than "
+            f"{INJECTION_OFFSET_MAX_EUR_KWH} EUR/kWh either way. Check its "
+            f"unit.")
+    return None
 
 
 def stale_card(spec: FormulaSpec, today=None):
@@ -568,15 +815,9 @@ def stale_card(spec: FormulaSpec, today=None):
     if dated is None or (now - dated).days <= CARD_STALE_DAYS:
         return None
     return (
-        f"price_formula's card is dated {spec.card_month}, which is "
-        f"{(now - dated).days} days ago. Suppliers reprice: if your contract "
-        f"has been renewed or rolled over since then, the coefficients here "
-        f"are last year's and every price this add-on computes is wrong by "
-        f"however far they moved - and the card self-check cannot see it, "
-        f"because it grades your coefficients against the card you typed, not "
-        f"the card against your current contract. Not refused: ENGIE freezes "
-        f"coefficients for the contract's duration, so an old card is often "
-        f"exactly right. Worth re-reading your klantenzone once.")
+        f"{spec.option}'s card is dated {spec.card_month}, "
+        f"{(now - dated).days} days ago. The add-on still starts, but if your "
+        f"contract changed since, copy the new figures from your supplier.")
 
 
 # --------------------------------------------------------------------------- #

goodwe_controller/app/freshness.py

@@ -175,6 +175,124 @@ only one of them is WIRED - see `BOUNDS` below and the note on SoC.
   integrator, and K. It does NOT owe a second freshness mechanism - `Freshness`
   below takes its obligation term from the caller precisely so that an energy
   integral can be handed in where command travel is handed in here.
+
+
+THE EXIT, AND WHY THE FIRST VERSION OF THIS MODULE DID NOT HAVE ONE (SAFETY-57)
+==============================================================================
+⚠️ THE VERDICT ABOVE IS ABOUT AN OBLIGATION, AND ITS OWN CONSEQUENCE REMOVES
+THE OBLIGATION. Declaring the reading stale makes `Controller.inputs_ok` False,
+which commands 0 W (§11.1 rule 1). At 0 W nothing is asking the register to be
+anywhere - `|standing| >= MOVE_W` is false, so the conjunction cannot arm - and
+the class docstring's clearing rule, "an arrival carrying a DIFFERENT number",
+asks the register for evidence that only a command could have produced. A pack
+sitting at its BMS floor answers the same integer watt for hours. **The state
+had no exit reachable from inside it**, and the operator-facing line said the
+opposite: *"It clears itself the moment the register reports a different
+value."*
+
+MEASURED ON THE LIVE SITE, 2026-09-21, and committed as
+`scenarios/safety57-2026-09-21/` - a passive RS-485 capture, decoded by
+`tools/decode_bus_capture.py`:
+
+    10:51:24.7   0x0518 reaches -3 W. The pack is at 11 % and the loop has just
+                 reversed from -447 W of charge into discharge; the BMS refuses
+                 and the inverter idles. The register is HEALTHY and TRUTHFUL.
+    10:51:29.7   the standing command reaches +1060 W. 800 W of travel, and the
+                 register is obliged to follow it.
+    10:52:00     the conjunction arms. `Inverter.batt` becomes None.
+    10:52:21.7   the site commands 0 W - on the wire, in the capture.
+    ...          0x0518 does not change value for 850.0 s. The setpoint does not
+                 change value for 790.0 s. Nothing in this add-on can end it.
+    11:04        a human restarts the add-on.
+    11:05:31.7   the restarted loop commands -400 W of charge, which the pack
+                 ACCEPTS at 11 %, and the register moves 3 s later.
+
+⚠️ AND IT HAD BEEN ESCAPING BY LUCK. This BMS emits a keep-alive pulse of a few
+hundred watts, which twitches 0x0518 and satisfies the clearing rule by
+accident. Replaying the committed 16-day loop capture
+(`scenarios/loop-2026-09-02_2026-09-17/`) through the shipped conjunction at
+1 Hz gives **93 trips**, and the time from each trip to the register's next
+change - which was the ONLY exit - has a median of 143 s, 17 episodes at or
+over the live one's 710 s, and a worst case of 21440 s. That distribution is a
+property of this battery's firmware. It is not a property of this code, and the
+add-on must not depend on it.
+
+THE RULE, and it is SAFETY-13's shape one module over - "which latches get an
+exit, not how long the block lasts":
+
+    RELEASE  <=>  the verdict is standing
+                  AND |standing command| < MOVE_W has held continuously for
+                      >= RELEASE_S
+
+On a release the latch clears and a NEW grading window opens at that instant:
+the register is re-graded, from scratch, against the commands issued AFTER it.
+Nothing about the register's own history is rewritten - `changed_mono`,
+`held` and `unchanged_s()` go on reporting that the register has not moved for
+850 s, because it has not.
+
+⚠️ `RELEASE_S` IS `BATT_OBLIGED_S`, 17.0 s, AND IT IS THE FLOOR OF ITS BAND
+RATHER THAN A PREFERENCE - the mirror of `MOVE_W` taking the ceiling of its
+own. The question the bound answers is *has the register had its chance to
+answer the command that is now standing?*, and that is exactly the 17.0 s
+already derived above: 6.0 s of plant, one 10 s publish, one 1 s read. Below it
+the release happens before the cheaper exit - the register moving by itself -
+could have occurred. Which half is safe is the opposite of SAFETY-13's, and for
+the reason that card states in its §4.2 table: being wrong LONG here is the
+failure being fixed (a site parked while it exports), and being wrong SHORT
+costs one re-grading window, which is bounded below.
+
+WHAT A RELEASE COSTS, MEASURED AND NOT ABSORBED - AND IT IS NOT SMALL. For the
+duration of the new window the consumers get the held number again, which is
+the exposure this module was written to close. Driven at the live install's
+shape against a register frozen for good (`test_freshness.py` part 10c), over
+1200 s:
+
+    shipped     parked 1166 s, the held number reaches a consumer  35 s   2.9 %
+    SAFETY-57   parked  571 s, the held number reaches a consumer 630 s  52.5 %
+
+⚠️ **52 % IS THE PRICE OF THE EXIT AND IT IS PAID EVERY CYCLE**, not an
+occasional slip. The period is the whole of `stale_input_s` (15 s) + `RELEASE_S`
+(17 s) parked, then one `BATT_UNCHANGED_S` (35 s) window of re-grading. It is
+bounded by construction, and that bound is the one thing that makes it payable:
+
+    the new window is AT MOST BATT_UNCHANGED_S = 35 s, and 35 < 75 < 85 - the
+    circulation hold and the per-unit sign hold. NEITHER CONSUMER CAN REACH A
+    VERDICT INSIDE ONE WINDOW, and a re-trip returns them a None, which CLEARS
+    both windows rather than accumulating into them.
+
+That inequality is the same one part 6 already grades, and it is why the window
+is `BATT_UNCHANGED_S` rather than a number chosen to make the table above look
+better. Neither detector can be made to say anything by a held number under
+this scheme - which is exactly the state the shipped code leaves them in as
+well, since a permanent None clears both windows for ever. **So nothing that
+SAFETY-37 detects is given back.** What the held number does reach for those
+35 s is `site_batt_w`, the anti-windup input of `control.compute()`, which
+responds to a large unexplained divergence by FREEZING the output - the
+conservative direction, and SAFETY-13's business. And the command itself is
+derived from the P1 meter, never from `batt`, so a site regulating through a
+re-grading window is regulating on the signal it always regulates on.
+
+**A register frozen under a command that never travels 250 W is still not
+detected at all** (survivor 2, unchanged), and a dead publisher whose value
+alternates is still invisible (survivor 3).
+
+⚠️ AND THE NARROWING THIS DOES NOT TAKE, named so the next card can. The live
+episode's register refused a DISCHARGE into an 11 % pack and then followed a
+CHARGE immediately; a refusal in one direction is not evidence about the other,
+and a gate that knew the pack's floor could re-grade on the first command that
+crosses it instead of on a timer. That needs SoC, which this module deliberately
+does not take (see the `soc` row), and the pack floor, which is SAFETY-32's
+number. It would shrink the 52 % above; it is not needed to give the state an
+exit, and mixing it in here would make the exit depend on a second measurement
+being right.
+
+⚠️ WHAT THIS DOES NOT DO, because the temptation is to call it a fix for the
+whole episode: it does not tell a BMS refusal apart from a dead register. The
+site above was parked for 790 s by a register that was working perfectly, and
+after this change it is parked for `stale_input_s + RELEASE_S` instead - about
+32 s on the shipped default - and then regrades. Telling the two apart needs
+the pack's own floor, which is SAFETY-32's number and not this module's input;
+the wording the operator reads about it is SAFETY-56's.
 """
 
 import time
@@ -211,6 +329,19 @@ BATT_UNCHANGED_S = 35.0
 # and goes red if the two drift.
 MOVE_W = 250.0
 
+# SAFETY-57. How long the obligation must have been ABSENT before a standing
+# verdict is withdrawn and the register re-graded. See the module docstring's
+# last section for the live episode this exists for and for which half of the
+# band is the safe one.
+#
+# ⚠️ IT IS `BATT_OBLIGED_S` AND NOT A NEW NUMBER, and that identity is the
+# derivation rather than a convenience. The question is "has the register had
+# its chance to answer the command standing NOW?", which is the same physical
+# quantity the floor of `BATT_UNCHANGED_S`'s band is: 6.0 s of plant, one 10 s
+# ESPHome publish, one 1 s add-on read. Releasing sooner would throw away the
+# cheaper exit - the register moving by itself - before it could have happened.
+RELEASE_S = BATT_OBLIGED_S   # 17.0
+
 
 @dataclass(frozen=True)
 class Bound:
@@ -219,6 +350,7 @@ class Bound:
     signal: str
     unchanged_s: float
     move_w: float
+    release_s: float
     wired: bool
     derivation: str
 
@@ -233,13 +365,19 @@ BOUNDS = {
         signal="batt (0x0518, AC power, S16, 1 W, 10 s publish)",
         unchanged_s=BATT_UNCHANGED_S,
         move_w=MOVE_W,
+        release_s=RELEASE_S,
         wired=True,
         derivation="settle 6.0 + publish 10.0 + read 1.0 = 17.0 s floor; "
-                   "circulation_hold_s 75 s ceiling; band [34.0, 37.5]"),
+                   "circulation_hold_s 75 s ceiling; band [34.0, 37.5]. "
+                   "SAFETY-57: the verdict is withdrawn after 17.0 s of the "
+                   "standing command below 250 W, because at 0 W the register "
+                   "is obliged to nothing and the verdict cannot be tested "
+                   "again from inside the state it creates"),
     "soc": Bound(
         signal="soc (0x050E, pack SoC, U16, 1 %, 10 s publish)",
         unchanged_s=float("inf"),
         move_w=float("inf"),
+        release_s=float("inf"),
         wired=False,
         derivation="TEL-08. Command travel is the WRONG obligation term for "
                    "SoC - a rested pack holds a percent for hours under a 0 W "
@@ -263,10 +401,33 @@ class Freshness:
     Declaring the reading stale makes `Controller.inputs_ok` False, which
     commands 0 W (§11.1 rule 1), which drops the standing command below
     `MOVE_W`, which un-arms the conjunction, which would return the held number
-    to the consumers - and round again every read. So the ONLY thing that clears
-    the latch is an arrival carrying a DIFFERENT number, which is exactly the
-    evidence the verdict was about. A register that is working clears it on its
-    next 10 s publish; a register that is not, does not.
+    to the consumers - and round again every read. So an arrival carrying a
+    DIFFERENT number clears the latch, which is exactly the evidence the verdict
+    was about. A register that is working clears it on its next 10 s publish; a
+    register that is not, does not.
+
+    ⚠️ AND IT IS NOT THE ONLY THING THAT CLEARS IT ANY MORE (SAFETY-57), BECAUSE
+    THAT MADE THE STATE INESCAPABLE FROM INSIDE. The command the verdict itself
+    produces is 0 W, and at 0 W the register is obliged to be nowhere - so
+    "report a different value" is evidence a parked site cannot ask for. The
+    live site sat at 0 W for 790 s on 2026-09-21 with a register that was
+    working correctly, and was freed by a human. `_release()` below withdraws a
+    verdict whose obligation has been gone for `bound.release_s`, and opens a
+    new grading window at that instant. The 1 Hz oscillation the latch exists to
+    prevent is still prevented: the new window is `bound.unchanged_s` wide, so
+    no re-trip can land sooner than 35 s after a release, rather than on the
+    next read. ⚠️ MEASURED FROM THE RELEASE, NOT FROM THE COMMAND RESUMING - if
+    the site rests for longer than the window before it asks for anything, the
+    window is already old and the re-trip lands on the first read at which the
+    command travels 250 W again. That is survivor 5's shape, it predates this
+    card, and its cost is one `stale_input_s` hold.
+
+    ⚠️ TWO CLOCKS, AND THE DISTINCTION IS THE WHOLE OF SAFETY-57'S HONESTY.
+    `changed_mono` / `held` are facts about the REGISTER: when it last carried a
+    different number. `graded_from` / `standing_at_grade` are the window the
+    VERDICT is computed over, which a release re-opens. They are the same thing
+    until the first release and diverge afterwards, and `unchanged_s()` - the
+    number an operator reads - is always the register's.
     """
 
     def __init__(self, bound: Bound):
@@ -281,10 +442,20 @@ class Freshness:
         # ability to fetch it.
         self.held = None
         self.changed_mono = None
-        # The standing command at that same instant. The conjunction compares
-        # against THIS, not against the previous cycle's command: what matters
-        # is whether the register has followed anything since it last moved.
-        self.standing_at_change = None
+        # SAFETY-57. The window the VERDICT is graded over, as opposed to the
+        # register's own history above, and the standing command at the instant
+        # it opened. The conjunction compares against THIS, not against the
+        # previous cycle's command: what matters is whether the register has
+        # followed anything since the current question was put to it. A register
+        # that moves opens a window, so until the first release these two are
+        # the change-stamps; `_release()` is where they diverge.
+        self.graded_from = None
+        self.standing_at_grade = None
+        # The instant the standing command last FELL below `move_w`, or None
+        # while an obligation is standing. The release timer runs off this.
+        self.rested_since = None
+        self.released_at = None
+        self.releases = 0
         self.stale = False
         self.reason = ""
         self.arrivals = 0
@@ -311,20 +482,67 @@ class Freshness:
         if self.changed_mono is None or value != self.held:
             self.held = value
             self.changed_mono = float(now_mono)
-            self.standing_at_change = (None if standing_w is None
-                                       else float(standing_w))
-            # Movement is the ONLY thing that clears the latch. See the class
-            # docstring on the 1 Hz oscillation this prevents.
+            self._open_window(standing_w, now_mono)
+            # Movement clears the latch, because it is exactly the evidence the
+            # verdict was about. See the class docstring on the 1 Hz oscillation
+            # the latch prevents, and `_release()` for the other way out.
             self.stale = False
             self.reason = ""
         self.last = value
+        # ⚠️ THE ORDER OF THESE TWO IS NOT OBSERVABLE, AND THIS COMMENT SAYS SO
+        # BECAUSE THE FIRST VERSION OF IT CLAIMED THE OPPOSITE. Swapping them is
+        # a ZERO-BYTE edit and it SURVIVED the battery; the reason is structural
+        # rather than a missing fixture, so no fixture could have closed it:
+        # `_grade()` acts only when `|standing| >= move_w` and `_release()` only
+        # when `|standing| < move_w`, so at most one of them can do anything on
+        # any given read, whichever runs first. Release is written first because
+        # it reads in the order the state machine moves - withdraw, then
+        # re-grade - not because the code depends on it.
+        self._release(standing_w, now_mono)
         self._grade(standing_w, now_mono)
 
+    def _open_window(self, standing_w, now_mono) -> None:
+        """Start grading the register again, from this instant (SAFETY-57).
+
+        Called when the register moves - the window and the register's history
+        coincide there - and when a verdict is withdrawn, where they do not.
+        """
+        self.graded_from = float(now_mono)
+        self.standing_at_grade = (None if standing_w is None
+                                  else float(standing_w))
+
+    def _release(self, standing_w, now_mono) -> None:
+        """SAFETY-57. Withdraw a verdict whose obligation is no longer standing.
+
+        ⚠️ THE TIMER RUNS ON THE COMMAND, NOT ON THE VERDICT. `rested_since` is
+        maintained on every arrival, latched or not, so the elapsed rest is the
+        real one and not "time since we last looked". An obligation reappearing
+        resets it to None, which is the whole point: a site that goes back to
+        asking the register for 250 W of movement has put the question back, and
+        the verdict stands until the question is withdrawn again.
+        """
+        obliged = (standing_w is not None
+                   and abs(float(standing_w)) >= self.bound.move_w)
+        if obliged:
+            self.rested_since = None
+            return
+        if self.rested_since is None:
+            self.rested_since = float(now_mono)
+        if not self.stale:
+            return
+        if float(now_mono) - self.rested_since < self.bound.release_s:
+            return
+        self.released_at = float(now_mono)
+        self.releases += 1
+        self.stale = False
+        self.reason = ""
+        self._open_window(standing_w, now_mono)
+
     def _grade(self, standing_w, now_mono) -> None:
         """The conjunction. Sets the latch; never clears it."""
-        if self.stale or self.changed_mono is None:
+        if self.stale or self.graded_from is None:
             return
-        held_s = self.unchanged_s(now_mono)
+        held_s = self.graded_s(now_mono)
         if held_s < self.bound.unchanged_s:
             return
         # ⚠️ BOTH None GUARDS ARE FOR A CALLER THAT DOES NOT KNOW ITS OWN
@@ -333,30 +551,98 @@ class Freshness:
         # consumer today. They are here for TEL-08, whose obligation term is an
         # energy integral that has nothing to say until it has a window - and
         # "nothing to say" must withhold the verdict, not manufacture one.
-        if standing_w is None or self.standing_at_change is None:
+        if standing_w is None or self.standing_at_grade is None:
             return
         standing_w = float(standing_w)
         if abs(standing_w) < self.bound.move_w:
             return
-        moved_w = abs(standing_w - self.standing_at_change)
+        moved_w = abs(standing_w - self.standing_at_grade)
         if moved_w < self.bound.move_w:
             return
         self.stale = True
+        # ⚠️ THE SENTENCE SAYS "unchanged", SO IT GETS THE REGISTER'S OWN
+        # NUMBER, NOT THE WINDOW'S. They are the same until the first release
+        # and different afterwards, and an operator comparing this line against
+        # a history graph is reading the register.
+        shown_s = self.unchanged_s(now_mono)
+        # ⚠️ SAFETY-56. THE OBSERVATION IS A FACT, THE DIAGNOSIS WAS NOT, AND
+        # THE SENTENCE NOW STOPS WHERE THE EVIDENCE DOES. The conjunction above
+        # is satisfied by TWO disjoint worlds, and nothing this object is handed
+        # separates them:
+        #   (1) the register has stopped reporting reality - what the gate was
+        #       built for - or
+        #   (2) reality is not moving, because the SOURCE cannot comply with
+        #       the command. A pack the BMS is refusing at its floor holds
+        #       still under any setpoint, and a register reporting that
+        #       truthfully publishes the same unchanged number a dead one does.
+        # The live 2026-09-21 episode was (2) - the pack read 11 % for the
+        # whole 850 s hold, the commands were discharge-only, and the register
+        # answered the first CHARGE command within one obligation window
+        # (test_freshness.py 11a measures all three off the committed capture)
+        # - and this sentence asserted (1), which sent the operator to look at
+        # healthy hardware.
+        # Naming both is what the module can honestly say. Naming WHICH would
+        # need SoC and the pack floor - deliberately not this module's inputs
+        # (see the `soc` row in BOUNDS and the docstring's last section), and
+        # TEL-08's and SAFETY-32's numbers rather than this sentence's.
+        #
+        # ⚠️ AND IT IS NOT SHARED WITH `main.py`'s NOT READY ROW, WHICH SAYS
+        # THE SAME AMBIGUITY IN DIFFERENT WORDS ON PURPOSE. This sentence is a
+        # LOG LINE about a behaviour, quoted verbatim by `note()` onto the
+        # status page and by `_read_unit()` into the action log; that one is a
+        # BANNER about a named ENTITY, and the two answer different questions
+        # ("what did the register do" against "can I trust this entity"). One
+        # helper serving both would have to drop whichever half the other does
+        # not need, and the half it dropped would be the operator's next step.
         self.reason = (
-            f"STALE_READING: {self.held:+.0f} unchanged for {held_s:.0f} s "
+            f"STALE_READING: {self.held:+.0f} unchanged for {shown_s:.0f} s "
             f"while the standing command moved {moved_w:.0f} W to "
-            f"{standing_w:+.0f} W - the reading is not following, so it is "
+            f"{standing_w:+.0f} W. TWO THINGS LOOK LIKE THIS AND THIS GATE "
+            f"CANNOT TELL THEM APART: the register may have stopped reporting "
+            f"reality, or the source may be unable to comply with the command "
+            f"- a pack the BMS is refusing holds still under any setpoint, and "
+            f"an honest register then reads exactly like a frozen one. Either "
+            f"way the number cannot be read as this command's effect, so it is "
             f"reported as MISSING rather than as a measurement (limits: "
             f"unchanged over {self.bound.unchanged_s:.0f} s, command over "
             f"{self.bound.move_w:.0f} W and moved by over "
             f"{self.bound.move_w:.0f} W)")
+        # ⚠️ SAFETY-57, AND THE THREE DURATIONS ARE THREE DIFFERENT FACTS, each
+        # in its own slot: the register's unchanged time is in the sentence
+        # above, the WINDOW this verdict actually rests on is here, and so is
+        # how many times this unit has been round the loop. Without the second
+        # one the sentence reads as though 92 s of unchanged register were what
+        # was compared against the 35 s limit, and it was not.
+        if self.releases:
+            self.reason += (
+                f" [re-graded: the {held_s:.0f} s window this verdict rests on "
+                f"opened when the previous one was withdrawn, not when the "
+                f"register last moved - this unit has now been graded "
+                f"{self.releases + 1} times]")
 
     def unchanged_s(self, now_mono) -> float | None:
-        """Seconds since an arrival carried a different number. Status page."""
+        """Seconds since an arrival carried a different number. Status page.
+
+        ⚠️ THE REGISTER'S CLOCK, NEVER THE VERDICT'S (SAFETY-57). A release
+        re-opens the grading window; it does not make the register younger, and
+        an operator reading "unchanged for 12 s" off a register that has held
+        one value for 850 s would be reading this module's bookkeeping back as a
+        measurement. `graded_s()` is the other one and is named differently for
+        that reason.
+        """
         if self.changed_mono is None:
             return None
         return max(0.0, float(now_mono) - self.changed_mono)
 
+    def graded_s(self, now_mono) -> float | None:
+        """Seconds the CURRENT verdict window has been open (SAFETY-57).
+
+        Equal to `unchanged_s()` until the first release, and shorter after one.
+        """
+        if self.graded_from is None:
+            return None
+        return max(0.0, float(now_mono) - self.graded_from)
+
     def reading(self):
         """What the consumers get: the value, or None when it cannot be trusted.
 
@@ -366,6 +652,13 @@ class Freshness:
         rather than accumulating it, and `circulation.circulating_w` returns None
         for a roster with a missing term, which clears the circulation window
         too. This module is the thing that was missing between them.
+
+        ⚠️ AND IT CAN GO BACK TO BEING A NUMBER WITHOUT THE REGISTER MOVING
+        (SAFETY-57). That is the exit, and it is bounded rather than free: the
+        window a release opens is `bound.unchanged_s` = 35 s, shorter than both
+        consumer holds (75 s and 85 s), so neither can reach a verdict inside
+        one - and a re-trip hands them a None, which CLEARS their windows. See
+        the module docstring's last section.
         """
         return None if self.stale else self.last
 
@@ -373,6 +666,26 @@ class Freshness:
         """One line for the status page. Empty when there is nothing to say."""
         return f"{unit_name}: {self.reason}" if self.stale else ""
 
+    def release_note(self, unit_name: str) -> str:
+        """SAFETY-57's release, for the log. Empty when nothing was withdrawn.
+
+        ⚠️ IT NAMES WHAT IS AND IS NOT BEING CLAIMED, because a line reading
+        "recovered" would be a lie: nothing has been learned about the register.
+        The verdict was withdrawn because it can no longer be tested, and the
+        next 35 s are the test.
+        """
+        if self.released_at is None:
+            return ""
+        return (f"{unit_name}: STALE_WITHDRAWN after the standing command sat "
+                f"below {self.bound.move_w:.0f} W for "
+                f"{self.bound.release_s:.0f} s. NOTHING HAS BEEN LEARNED ABOUT "
+                f"THE REGISTER - it is still holding {self.held:+.0f} - but a "
+                f"verdict about a command that is no longer standing cannot be "
+                f"tested, and the 0 W this one produces is what stopped it "
+                f"being tested. The register is now re-graded over a fresh "
+                f"{self.bound.unchanged_s:.0f} s window; if it still does not "
+                f"follow, this returns")
+
 
 def monotonic() -> float:
     """The clock this module's callers use, in one place so tests can find it.

goodwe_controller/app/hass.py

@@ -61,10 +61,17 @@ class HomeAssistant:
                 if resp.status == 404:
                     return None
                 resp.raise_for_status()
-                return await resp.json()
-        except (aiohttp.ClientError, TimeoutError) as err:
+                obj = await resp.json()
+        # SAFETY-61: an undecodable body is an absence like any other failed
+        # read, never an exception into the control loop.
+        except (aiohttp.ClientError, TimeoutError, ValueError) as err:
             self._moan(f"read:{entity_id}", "read %s failed: %s", entity_id, err)
             return None
+        if not isinstance(obj, dict):
+            self._moan(f"shape:{entity_id}", "read %s: not a state object: %.80r",
+                       entity_id, obj)
+            return None
+        return obj
 
     async def number(self, entity_id: str, invert: bool = False) -> float | None:
         """Numeric state, or None. Never substitutes a default."""
@@ -117,7 +124,8 @@ class HomeAssistant:
                                domain, service, resp.status, body[:200])
                     return False
                 return True
-        except (aiohttp.ClientError, TimeoutError) as err:
+        # ValueError: an undecodable error body (SAFETY-61) is a failed write.
+        except (aiohttp.ClientError, TimeoutError, ValueError) as err:
             self._moan(f"svcerr:{domain}.{service}", "service %s.%s failed: %s",
                        domain, service, err)
             return False

goodwe_controller/app/inverter.py

@@ -123,6 +123,7 @@ from datetime import datetime
 
 from .clamp import ClampResult
 from .delivery import DeliveryConfig, DeliveryWatchdog
+from . import messages
 # SAFETY-37. The freshness policy, and the ONE place its bounds are written.
 # freshness.py imports nothing from this package, so the direction is one-way.
 from .freshness import BOUNDS, Freshness
@@ -407,21 +408,24 @@ class Inverter:
         stop the site (`inputs_ok`). Folding one into the other is how a
         measurement fault ends up handing a sibling extra power.
         """
-        return self.batt_fresh.note(self.name)
+        return (messages.row_battery_stuck(self.name) if self.batt_fresh.stale
+                else "")
 
     def link_note(self, now: datetime) -> str:
-        """One line for the status page. Empty when there is nothing to say."""
+        """One line for the status page. Empty when there is nothing to say.
+
+        The words are `app/messages.py`'s (UX-09). main.py colours the row red
+        exactly when `is_live()` is False.
+        """
         if not self.has_writer():
-            return (f"{self.name}: NO SETPOINT ENTITY - this controller cannot "
-                    f"command it, and the site refuses rather than running at "
-                    f"part strength")
-        live, why = self.is_live(now)
+            return messages.row_no_setpoint(self.name)
+        live, _why = self.is_live(now)
+        held = (0.0 if self.rejected_since is None
+                else (now - self.rejected_since).total_seconds())
         if not live:
-            return f"{self.name}: NOT COMMANDABLE - {why}"
+            return messages.row_not_controllable(self.name, held, LINK_STALE_S)
         if self.rejected_since is not None:
-            held = (now - self.rejected_since).total_seconds()
-            return (f"{self.name}: writes rejected for {held:.0f} s - still "
-                    f"commandable until {LINK_STALE_S:.0f} s")
+            return messages.row_commands_refused(self.name, held, LINK_STALE_S)
         return ""
 
     def __repr__(self) -> str:

goodwe_controller/app/mqtt.py

@@ -85,8 +85,114 @@ SENSORS = [
     # sensor's VALUE rather than its arrival, so a dead publisher freezes the
     # number and reads permanently fresh. Filed as TEL-06.
     ("p1_age", "p1_sample_age_s", "P1 sample age", "s", "duration", "measurement", None),
+    # --- TEL-10: the loop's integrator, published for the first time ---------
+    #
+    # ⚠️ APPENDED, AND THE POSITION IS THE POINT. `discovery_payloads()` walks
+    # this list in order and `_announce()` publishes what it returns, so a row
+    # inserted ABOVE would move every later entity's place in the announcement.
+    # Nothing existing is renamed, re-typed or re-ordered by these three; they
+    # are three NEW retained topics after the nine that are already there, and
+    # test_mqtt.py part 1 grades exactly that claim.
+    #
+    # ⚠️ AND THEY ARE SITE ROWS, NOT PER-UNIT ONES. There is one integrator -
+    # §6.2's architecture is ONE integrator on the P1 meter whose output is then
+    # SPLIT - so a per-unit copy would invent N of a thing there is one of, the
+    # same argument `grid` and `p1_age` are site rows for.
+    #
+    # `state_class: measurement` on the two numbers is what puts them in the
+    # recorder's statistics, which is the whole point: the reason this card
+    # exists is that the last investigation had no history to read.
+    ("loop_i", "goodwe_loop_integrator", "Loop integrator", "W", "power", "measurement", None),
+    # ⚠️ NOT DERIVABLE FROM THE TWO ROWS EITHER SIDE OF IT, which is why it is
+    # its own row rather than a subtraction a dashboard could do. `setpoint` is
+    # the ARBITER's output after every other strategy has had its say, and it is
+    # also THIS cycle's; the lead is measured against the command `compute()`
+    # was handed, which is the PREVIOUS one. Subtracting the published rows
+    # gives a different number on every cycle the arbiter overrode the loop.
+    ("loop_lead", "goodwe_loop_integrator_lead", "Loop integrator lead", "W", "power", "measurement", None),
+    # ⚠️ NOT `sensor.goodwe_controller_status` AND NOT THE "Why" ROW. Both of
+    # those carry the ARBITER's sentence; this is `compute()`'s own word for
+    # what the control law did with this cycle - `slew-limited` is the value
+    # SAFETY-48 is about and it appears in neither of the other two.
+    ("loop_reason", "goodwe_loop_reason", "Loop reason", None, None, None, "mdi:sigma"),
 ]
 
+# --- TEL-11: rows that exist ONLY when the operator configured a source ------
+#
+# ⚠️ A SECOND LIST RATHER THAN A TENTH ENTRY IN `SENSORS`, AND THE DEFAULT IS
+# WHAT MAKES IT ONE. `SENSORS` is announced by every caller of
+# `discovery_payloads()`; `OPTIONAL_SENSORS` is announced only by a caller that
+# ASKS, so a caller that has not been taught about `pv_entity` - `test_mqtt.py`'s
+# fixtures, `tools/rehearse_roster.py`, anything written next year - announces
+# exactly what it announced before. `p1_age` solves the same problem the other
+# way round, with `omit`, because `p1_age` is announced by DEFAULT and withdrawn
+# when the meter is off; this one does not exist by default and appears when a
+# source for it does. Getting that direction wrong is the hazard `omit`'s own
+# note names: an entity that exists and is never fed is a worse signal than one
+# that does not exist at all, and MOST installs will never set `pv_entity`.
+#
+# ⚠️ `state_class: measurement` IS THE WHOLE POINT OF THE ROW. It is what puts
+# the number into the recorder's long-term statistics, and a week of statistics
+# is what OPT-10 needs to say whether the surplus that left this site was cloud,
+# a charge-power limit, or the optimiser declining to charge.
+OPTIONAL_SENSORS = [
+    ("pv", "goodwe_pv_power", "PV power", "W", "power", "measurement", None),
+]
+
+# ⚠️ HA's OWN "this sensor has no value" PAYLOAD, and the one place this add-on
+# spells it. `homeassistant/components/mqtt/const.py` declares
+# `PAYLOAD_NONE = "None"` and `mqtt/sensor.py` tests it BEFORE the numeric
+# branch - `if payload == PAYLOAD_NONE: self._attr_native_value = None` - so the
+# entity's state becomes `unknown` rather than a number. (Read out of
+# github.com/home-assistant/core `dev` on 2026-09-24; the shipped MQTT-sensor
+# documentation says the same thing in its `state_topic` entry: "a 'None' value
+# will set the sensor to an unknown state".)
+PAYLOAD_NONE = "None"
+
+# The keys whose ABSENCE MUST BE PUBLISHED rather than skipped. ⚠️ THIS IS THE
+# DIFFERENCE BETWEEN "no PV reported" AND "PV reported 0 W" IN A WEEK OF
+# HISTORY, AND WITHOUT IT THE CHANNEL LIES IN THE WORSE DIRECTION. `publish()`
+# below drops a `None` - which is right for `circulation`, where the last figure
+# standing is better than a zero that reads as health - but a DROPPED pv row
+# leaves Home Assistant holding the last number it was told, forever, and the
+# recorder then draws a flat line at that value through an outage. Someone
+# reading it back would conclude the sun was not shining, which is precisely the
+# conclusion this card exists to TEST rather than to manufacture.
+ABSENT_AS_UNKNOWN = frozenset({"pv"})
+
+
+def optional_keys(opts: dict) -> tuple:
+    """Which `OPTIONAL_SENSORS` rows this configuration has a source for.
+
+    ⚠️ ONE ANSWER TO "IS THE PV ROW LIVE", read by the ANNOUNCEMENT (through
+    `MqttPublisher`) and by `Controller.publish()`. `announced_units()` above
+    exists for exactly this reason and says it in full: two spellings of one
+    predicate is how an entity gets announced that nothing feeds, or fed on a
+    topic nothing announced.
+
+    ⚠️ AND SINCE TEL-12 IT IS `pv.entities()` RATHER THAN A SECOND READING OF
+    THE OPTION - `Controller.pv_roster` is the SAME call. TEL-11 got away with
+    two spellings because both were `bool()` of one string; with `pv_entities`
+    beside `pv_entity`, and `pv_entities` REPLACING it, a second spelling is how
+    the row gets announced off one key and summed off the other. ⚠️ THE ROW IS
+    ONE SITE TOTAL AT EVERY ROSTER SIZE: there is deliberately no per-entity
+    topic, because the recorder statistic OPT-10 reads back is the site figure
+    and a per-inverter breakdown is a dashboard question the operator's own PV
+    integration already answers.
+    """
+    # ⚠️ THE IMPORT IS FUNCTION-LOCAL AND THAT IS NOT A STYLE CHOICE. This
+    # module is EXEC'D STANDALONE, outside its package, by `test_mqtt.py`
+    # part 8's mutation harness - which says so in its own comment, and whose
+    # honesty depends on it ("`app/mqtt.py` imports nothing from this package,
+    # which is what makes exec'ing it standalone honest rather than a stub").
+    # A module-scope `from . import pv` turns that whole instrument into an
+    # `ImportError` before it grades anything. `tools/tel11_pv_trace.py`'s
+    # `_load()` is the same decision for the same kind of reason. Measured, not
+    # assumed: move this line to module scope and test_mqtt.py part 8 dies.
+    from . import pv as _pv
+    return ("pv",) if _pv.entities(opts) else ()
+
+
 BASE = "goodwe_ctl"
 AVAILABILITY = f"{BASE}/availability"
 
@@ -269,15 +375,23 @@ def _payload(name, object_id, unique_id, state_topic, device,
     return cfg
 
 
-def discovery_payloads(units=(), omit=()) -> list:
+def discovery_payloads(units=(), omit=(), include=()) -> list:
     """Every `(topic, payload)` this add-on announces, in announcement order.
 
     Split out of `_announce()` so that the acceptance criterion can be graded as
     a DIFF OF THE ANNOUNCED PAYLOADS against `release/1.0`, rather than as a
     reading of the code. `_announce()` publishes exactly this list and nothing
     else, which is itself checked.
+
+    `include` names `OPTIONAL_SENSORS` keys to announce. ⚠️ IT DEFAULTS TO
+    NOTHING AND THE ROWS GO LAST, so no existing row's POSITION moves under any
+    configuration - not the site rows, not the per-unit ones. Order is part of
+    the output here (`_payload()`'s note, and test_mqtt.py part 1 asserts an
+    ordered LIST precisely because a re-order is a zero-byte edit that
+    re-announces every entity on a live install).
     """
     omit = set(omit)
+    include = [k for k in include if k not in omit]
     out = []
     for key, object_id, name, unit, dev_class, state_class, icon in SENSORS:
         if key in omit:
@@ -306,12 +420,19 @@ def discovery_payloads(units=(), omit=()) -> list:
                          unique_id,
                          f"{BASE}/{unit_state_key(slug, key)}",
                          device, unit, dev_class, state_class, icon)))
+    for key, object_id, name, unit, dev_class, state_class, icon in OPTIONAL_SENSORS:
+        if key not in include:
+            continue
+        out.append((
+            f"homeassistant/sensor/{BASE}_{key}/config",
+            _payload(name, object_id, f"{BASE}_{key}", f"{BASE}/{key}",
+                     DEVICE, unit, dev_class, state_class, icon)))
     return out
 
 
 class MqttPublisher:
     def __init__(self, host, port, username=None, password=None, omit=(),
-                 units=()):
+                 units=(), include=()):
         # `omit` drops sensor keys from discovery entirely. ⚠️ Announcing a
         # sensor that nothing will ever publish to is not harmless here:
         # p1_sample_age_s is a watchdog input, and an entity that exists but is
@@ -323,6 +444,10 @@ class MqttPublisher:
         # per-unit is announced, so every caller that has not been taught about
         # the roster keeps publishing what it published before.
         self.units = [str(u) for u in units]
+        # TEL-11. `mqtt.optional_keys(opts)` - the shipped predicate, not a
+        # second reading of the option. Defaults to empty, so a caller that has
+        # not been taught about it announces exactly what it announced before.
+        self.include = [str(k) for k in include]
         self.enabled = mqtt is not None and bool(host)
         self.client = None
         if not self.enabled:
@@ -359,7 +484,8 @@ class MqttPublisher:
         # announcement, so the check that diffs it against `release/1.0` is
         # diffing what actually goes on the wire - and a payload built here
         # instead would be one this add-on publishes and no check has ever seen.
-        for topic, cfg in discovery_payloads(self.units, self.omit):
+        for topic, cfg in discovery_payloads(self.units, self.omit,
+                                             self.include):
             self.client.publish(topic, json.dumps(cfg), retain=True)
         self.client.publish(AVAILABILITY, "online", retain=True)
 
@@ -369,7 +495,16 @@ class MqttPublisher:
         try:
             for key, value in values.items():
                 if value is None:
-                    continue
+                    # ⚠️ TEL-11. A DROPPED ROW IS NOT AN ABSENT ROW. Skipping
+                    # leaves Home Assistant holding the last value it was told,
+                    # which is what `circulation` wants (its note in main.py
+                    # says why) and is exactly wrong for a measurement somebody
+                    # will read back as history: a flat line at the last number
+                    # is indistinguishable from a real one. See
+                    # `ABSENT_AS_UNKNOWN`.
+                    if key not in ABSENT_AS_UNKNOWN:
+                        continue
+                    value = PAYLOAD_NONE
                 self.client.publish(f"{BASE}/{key}", str(value))
         except OSError as err:  # pragma: no cover
             _LOG.debug("MQTT publish failed: %s", err)

goodwe_controller/app/p1.py

@@ -47,6 +47,10 @@ from datetime import datetime, timezone
 
 import aiohttp
 
+from . import messages
+
+_S = messages.setting   # a refusal names the setting by its label (UX-08)
+
 try:
     import paho.mqtt.client as mqtt
 except ImportError:  # pragma: no cover - container always has it
@@ -180,7 +184,8 @@ def make_sample(source: str, import_w, export_w, *, phases: int,
     # already applied a sign we are about to apply again - reject it rather
     # than silently double-signing the control loop.
     if imp < 0 or exp < 0:
-        raise P1Error(f"unsigned registers cannot be negative (import={imp:g} export={exp:g})")
+        raise P1Error(f"import and export readings cannot be negative "
+                      f"(import={imp:g} export={exp:g})")
 
     per_phase = per_phase_import = None
     if phase_import_w is not None or phase_export_w is not None:
@@ -188,8 +193,8 @@ def make_sample(source: str, import_w, export_w, *, phases: int,
         pe = list(phase_export_w or [0.0] * len(pi))
         if len(pi) != phases or len(pe) != phases:
             raise P1Error(
-                f"phase count mismatch: telegram has {len(pi)} import / {len(pe)} export "
-                f"phases, meter_phases is {phases}")
+                f"the meter sent {len(pi)} import and {len(pe)} export phases, "
+                f"but {_S('meter_phases')} is {phases}")
         vals = [_watts(a, f"L{i + 1} import") - _watts(b, f"L{i + 1} export")
                 for i, (a, b) in enumerate(zip(pi, pe))]
         per_phase = tuple(vals)
@@ -467,7 +472,7 @@ class P1Ingest:
         """
         self.parse_errors += 1
         self.last_error = str(err)
-        _LOG.warning("P1 telegram rejected: %s", err)
+        _LOG.warning("A meter message could not be read: %s", err)
 
     # -- what consumers read -------------------------------------------------
     def age_s(self) -> float | None:
@@ -1160,37 +1165,37 @@ def validate_meter_options(opts: dict, phases: int, max_age_s: float) -> list[st
         exp = str(opts.get("p1_export_entity", "") or "").strip()
         if not imp or not exp:
             problems.append(
-                f"meter_source {SOURCE_HA} needs both p1_import_entity and "
-                f"p1_export_entity (got {imp or '<blank>'!r} / {exp or '<blank>'!r})")
+                f"{_S('meter_source')} is {SOURCE_HA!r}, so it needs "
+                f"{_S('p1_import_entity')} and {_S('p1_export_entity')}. They "
+                f"are {messages.shown(imp)} and {messages.shown(exp)}.")
     elif source == SOURCE_HA_SIGNED:
         net = str(opts.get("p1_net_entity", "") or "").strip()
         phase_net = [str(e).strip() for e in
                      (opts.get("p1_phase_net_entities") or []) if str(e).strip()]
         if not net:
             problems.append(
-                f"meter_source {SOURCE_HA_SIGNED} needs p1_net_entity "
-                "(sensor.p1_sample_age_s would otherwise be announced with "
-                "nothing feeding it)")
+                f"{_S('meter_source')} is {SOURCE_HA_SIGNED!r}, so it needs "
+                f"{_S('p1_net_entity')}.")
         if phase_net and len(phase_net) != phases:
             problems.append(
-                f"p1_phase_net_entities has {len(phase_net)} entities but "
-                f"meter_phases is {phases} - every telegram would be rejected "
-                "on the phase-count check")
+                f"{_S('p1_phase_net_entities')} has {len(phase_net)} entities, "
+                f"but {_S('meter_phases')} is {phases}. Make them match.")
     elif source == SOURCE_MQTT:
         if not str(opts.get("meter_mqtt_topic", "") or "").strip():
-            problems.append(f"meter_source {SOURCE_MQTT} needs meter_mqtt_topic")
+            problems.append(f"{_S('meter_source')} is {SOURCE_MQTT!r}, so it "
+                            f"needs {_S('meter_mqtt_topic')}.")
     elif source == SOURCE_HOMEWIZARD:
         host, port_s = homewizard_host_port(opts)
         if not host:
             problems.append(
-                f"meter_source {SOURCE_HOMEWIZARD} needs p1_host (the meter's "
-                "own address, e.g. 192.168.2.250)")
+                f"{_S('meter_source')} is {SOURCE_HOMEWIZARD!r}, so it needs "
+                f"{_S('p1_host')}, the meter's address on your network.")
         if port_s:
             try:
                 int(port_s)
             except ValueError:
-                problems.append(f"p1_host {opts.get('p1_host')!r} has an "
-                                "unparseable port")
+                problems.append(f"{_S('p1_host')} is {messages.shown(opts.get('p1_host'))}, and "
+                                "its port is not a number.")
         try:
             # ⚠️ Not `or 5`: that turns an explicit 0 into the default, and a
             # cadence of 0 is a misconfiguration that must be reported, not
@@ -1198,23 +1203,26 @@ def validate_meter_options(opts: dict, phases: int, max_age_s: float) -> list[st
             raw = opts.get("meter_poll_s", 5)
             poll_s = float(5 if raw is None or raw == "" else raw)
         except (TypeError, ValueError):
-            problems.append(f"meter_poll_s {opts.get('meter_poll_s')!r} is not a number")
+            problems.append(f"{_S('meter_poll_s')} is "
+                            f"{messages.shown(opts.get('meter_poll_s'))}, which is not a "
+                            "number.")
         else:
             if poll_s <= 0:
-                problems.append("meter_poll_s must be positive")
+                problems.append(f"{_S('meter_poll_s')} must be above 0.")
             # ⚠️ The age can never be fresher than the poll interval. At or past
             # max_age_s every reading is stale before its successor arrives, so
             # the controller would sit permanently on missing inputs while the
             # meter is perfectly healthy - refuse it rather than ship that.
             elif poll_s >= max_age_s:
                 problems.append(
-                    f"meter_poll_s {poll_s:.1f} is not under meter_max_age_s "
-                    f"{max_age_s:.1f} - every reading would go stale before the "
-                    "next poll")
+                    f"{_S('meter_poll_s')} is {poll_s:.1f}, not below "
+                    f"{_S('meter_max_age_s')} at {max_age_s:.1f}. Poll more "
+                    "often, or every reading goes stale.")
     else:
         problems.append(
-            f"meter_source {source!r} is not one of "
-            + ", ".join((SOURCE_HA, SOURCE_MQTT, SOURCE_HA_SIGNED, SOURCE_HOMEWIZARD)))
+            f"{_S('meter_source')} is {source!r}. Choose one of: off, "
+            + ", ".join((SOURCE_HA, SOURCE_MQTT, SOURCE_HA_SIGNED, SOURCE_HOMEWIZARD))
+            + ".")
     return problems
 
 
@@ -1261,9 +1269,8 @@ def build_source(opts: dict, ingest: P1Ingest, session, broker: dict | None):
         # 0 W cycle, which is fail-safe. The refusal above is for cadences that
         # can NEVER be fresh.
         if poll_s > ingest.max_age_s / 2:
-            _LOG.warning("meter_poll_s %.1f leaves no room under meter_max_age_s "
-                         "%.1f: one missed poll makes the reading stale. The meter "
-                         "updates every ~5 s; 5 s against 30 s is the tested pair.",
+            _LOG.warning("“Time between meter reads” (%.1f s) is too close to "
+                         "“Reading too old after” (%.1f s). Use 5 s and 30 s.",
                          poll_s, ingest.max_age_s)
         return HomeWizardLocalSource(session, ingest, host, port=port, poll_s=poll_s)
     if source == SOURCE_MQTT:

goodwe_controller/app/peakguard.py

@@ -395,6 +395,7 @@ not need re-testing. Nothing here indexes a phase.
 
 from dataclasses import dataclass
 
+from . import messages
 from .arbiter import ACTUATOR_SITE, P_PEAK, Claim
 from .control import peak_at_risk
 from .tariff import QUARTER_S
@@ -485,17 +486,29 @@ class PeakDecision:
     reason: str = ""
 
     def explain(self) -> str:
+        """Idle: the status row's plain words (UX-08). Engaged: `reason`, the
+        technical record with every figure, for the log and the action log."""
         if self.floor_limited:
             return self.reason
         if not self.engaged:
             if self.projected_w is None:
-                return f"peak guard idle - {self.reason}"
-            return (f"peak guard idle - quarter projects "
-                    f"{self.projected_w:.0f} W under a {self.ceiling_w:.0f} W "
-                    f"ceiling ({self.ceiling_from})")
+                return messages.row_peak_guard_quiet()
+            return messages.row_peak_guard_idle(
+                self.projected_w, self.ceiling_w,
+                month_peak=self.ceiling_from == CEILING_MONTH_PEAK)
         return self.reason
 
 
+def blind_kind(blind: str) -> str:
+    """Which of the three kinds of blindness, as a key of
+    `messages.BLIND_WORDS`, for the status row."""
+    if blind == BLIND_FROZEN:
+        return "frozen"
+    if blind == BLIND_NO_BLOCK:
+        return "no_block"
+    return "gap"
+
+
 def quarter_ceiling_w(cap_w, reading) -> tuple[float, str]:
     """The average this quarter may not exceed, and where the number came from.
 
@@ -822,6 +835,145 @@ def decide(projection, *, batt_w, cap_w, reading, achievable_w, soc, soc_floor,
                f"only give {ceil_top:.0f} W" if saturated else "")))
 
 
+def charge_headroom_w(decision) -> float | None:
+    """SAFETY-45. The hardest this SITE may charge without putting the billed
+    quarter over the ceiling, in W, positive - or None when nothing measured it.
+
+    THE ONE PLACE THIS QUESTION IS ANSWERED, and it is public for the reason
+    `discharge_permitted()`, `shaping_suspended()`, `guard_state()` and
+    `looks_frozen()` are: the check that grades it has to assert on THE SHIPPED
+    EXPRESSION, and a predicate transcribed into its own test is one copy plus a
+    future disagreement about what the check means.
+
+    ------------------------------------------------------------------------
+    THE DEFECT IT PREVENTS, AND IT IS NOT A NEW IDEA IN THIS REPOSITORY
+
+    `control.maintenance_charge_floor()` already caps MAINTENANCE charging at
+    "the headroom left under the site's cap", and its docstring says why in
+    words this card only has to widen:
+
+        "A maintenance charge is the only thing this system does that is big
+        enough and long enough to set that peak, so it is capped by the
+        headroom left under the site's cap."
+
+    ⚠️ THAT SENTENCE STOPPED BEING TRUE WHEN OPT-04 LANDED. Price arbitrage is a
+    SECOND thing that is big enough and long enough - it commands `max_w` for a
+    whole tariff interval, deliberately, against the meter - and it was given no
+    such cap. Measured on TEST-23 stage 3's closed rig at the shipped
+    `peak_cap_w: 3500` / `max_w: 2000`: 28 charge onsets in one hour, mean period
+    131 s, grid swinging -456 <-> +3200 W, on any house drawing over 1500 W in
+    the cheapest quarter. §10.2: "an EMS that oscillates is worse than no EMS,
+    both for hardware wear and - per §9.1 - for the peak it is trying to avoid."
+
+    ⚠️ AND IT IS THE **MEASURED** GUARD, NOT `peak_forecast_entity`.
+    `maintenance_charge_floor()` sizes itself from the forecast sensor, which is
+    OPTIONAL and empty on a default install - the exact hole SAFETY-25 had to
+    close in `shaping_suspended()`, where a suspension gated on the forecast
+    alone could not fire on the very site that needed it. This number comes off
+    `decide()`, which runs wherever P1 does.
+
+    ------------------------------------------------------------------------
+    WHERE THE NUMBER COMES FROM: IT IS `wanted_w`, READ IN THE OTHER DIRECTION
+
+    `decide()` already computes
+
+        wanted = batt_w + excess = (the offtake there would be with the battery
+                 at zero) - (the level this quarter can still afford)
+
+    as the battery DISCHARGE that would land the quarter exactly on the ceiling.
+    A negative `wanted` is not "nothing to say" - it is a permitted CHARGE of
+    `-wanted` watts, and throwing it away is SAFETY-45's whole defect. So this
+    function invents no arithmetic; it reads the sign the guard already had.
+
+    ⚠️ AND THE QUANTITY IS INVARIANT IN THE BATTERY, WHICH IS WHY SIZING A TRADE
+    TO IT CANNOT OSCILLATE. Raise the charge by dW and the meter rises by dW, so
+    `excess` rises by exactly dW while `batt_w` falls by dW: `wanted` does not
+    move. It is a FEED-FORWARD number - a function of the house, the ceiling and
+    the seconds already banked - so consuming it adds no feedback path around the
+    plant. The fixed point is `charge = ceiling - load`, with the meter sitting
+    ON the ceiling and `wanted` parked at `load - ceiling`, a whole `ceiling -
+    load` clear of the engagement boundary rather than chattering across it.
+
+    ⚠️ AND A QUARTER BOUNDARY DOES NOT HAND IT BACK AT FULL POWER, WHICH IS THE
+    OTHER HALF OF SAFETY-45 AND IS NOT THE SAME CLAIM AS "IT DOES NOT CHANGE".
+    It DOES change - it is `(900 / remaining) * (ceiling - projected)`, so it is
+    largest in the last seconds of a block and collapses at the boundary. What
+    matters is WHAT IT COLLAPSES TO: at `elapsed = 0` the projection IS the held
+    level, so the answer is `ceiling - (load - pv)` - the house and the cap, and
+    nothing else. A trade refused at 14:59 therefore resumes at 15:00 at the rate
+    the new quarter can afford, not at `max_w`, and §10.1's answer survives the
+    boundary because the arithmetic does: no timer, no backoff constant, no state
+    carried between calls.
+
+    ⚠️ AND THE AMPLIFICATION IS BOUNDED IN ITS EFFECT, NOT MERELY LARGE. Hold a
+    charge of exactly this size for the rest of the block and the block's average
+    lands on `ceiling` EXACTLY, wherever in the block it started:
+
+        (acc + (held + headroom) * remaining) / 900
+            = projected + (900/remaining) * (ceiling - projected) * remaining/900
+            = ceiling
+
+    so 162 kW of headroom with 5 s left and 900 W of it with the whole quarter to
+    go are the same statement about the bill. `test_peakguard.py` part 13 sweeps
+    that identity across the block rather than arguing it here.
+
+    ------------------------------------------------------------------------
+    THE THREE ANSWERS
+
+    `None`  nothing measured it: the guard never ran (`meter_source: off`), or
+            it ran with no battery reading to size a floor from, or the block
+            had no seconds left to influence. ⚠️ None IS NOT UNLIMITED. A caller
+            that treats it as "charge away" is `arbitrage.guard_state()`'s
+            collapse of None into False, one layer down - a strategy creating
+            the billed quantity while nothing measures the quarter it lands in.
+    `0.0`   measured, and the answer is no charging: the guard is BLIND (its
+            claim already says so at `floor 0 W` and this agrees with it rather
+            than restating it), or it is holding and `wanted >= 0`.
+    `> 0`   the watts a charge may pull this cycle.
+
+    ⚠️ HOLDING IMPLIES ZERO, BY CONSTRUCTION AND NOT BY COINCIDENCE. Every state
+    that files a claim with `engaged=True` has `wanted > 0`, `wanted is None` or
+    `blind`, so this answers 0.0 or None there and can never hand a strategy
+    permission the guard's own `lo` is at that instant refusing.
+
+    ------------------------------------------------------------------------
+    ⚠️ WHY THIS IS A SIZING AND NOT A CLAIM, AND DO NOT "SIMPLIFY" IT INTO ONE
+
+    The obvious tidier answer is to delete `decide()`'s `wanted <= 0` gate and
+    let it file `lo = wanted` unconditionally - a NEGATIVE floor, meaning "you
+    may charge, but no harder than this". The arithmetic is identical, it is
+    continuous, and it would bind every claimant rather than only arbitrage. It
+    was measured, considered and REJECTED, and the reason is not style:
+
+      * `main.py`'s cheap-window maintenance charge files
+        `Claim.limit("maintenance", P_MAINT_SHAPE, hi=-floor)` - a NEGATIVE `hi`.
+        arbiter.py clause 2 applies EVERY limit at or above the winner's priority
+        and takes the most restrictive, with no notion of one limit out-ranking
+        another. A peak `lo = -300 W` against a shaping `hi = -1000 W` is
+        `lo > hi`: a CONTRADICTION, which resolves to 0 W - the battery PARKED,
+        in the one quarter of the month that sets the bill. That is the exact
+        failure `shaping_suspended()` exists to prevent, and the only way to
+        close it would be to key that suppression on "a claim exists", which on
+        every site this card is about suspends the maintenance charge-only
+        shaping PERMANENTLY.
+      * and it would change what `engaged` MEANS at five call sites outside this
+        module - `arbitrage.guard_state()`, `shaping_suspended()`, `claim()`,
+        main.py's edge-logged action line and main.py's status row - each of
+        which today reads it as "the guard is HOLDING".
+
+    `control.maintenance_charge_floor()` is a sizing and not a limit for the same
+    reason, which is why this is the shape that already fits.
+    DECISIONS/SAFETY-45-sizing-the-trade.md §2b carries the full argument.
+    """
+    if decision is None:
+        return None
+    if decision.blind:
+        return 0.0
+    if decision.wanted_w is None:
+        return None
+    return max(0.0, -float(decision.wanted_w))
+
+
 def shaping_suspended(decision, peak_forecast_w, cap_w) -> bool:
     """Must the maintenance charge-only shaping stand down this cycle?
 

goodwe_controller/app/price.py

@@ -151,8 +151,8 @@ from textwrap import dedent
 from urllib.parse import urlencode
 
 from .custom_formula import (
-    FormulaInvalid, PREVIEW_HOURS, parse_price_formula, preview_lines,
-    price_eur_kwh, to_resolution)
+    EXPORT_FORMULA_OPTION, FormulaInvalid, PREVIEW_HOURS, parse_export_formula,
+    parse_price_formula, preview_lines, price_eur_kwh, to_resolution)
 
 _LOG = logging.getLogger("goodwe.price")
 
@@ -818,6 +818,69 @@ def plan_is_provisional(read: PriceRead) -> bool:
 # Options: what a plugin may see, and what it may not
 # --------------------------------------------------------------------------- #
 
+# --------------------------------------------------------------------------- #
+# TARIFF-18: what `price_taxes_eur_kwh` IS MADE OF
+# --------------------------------------------------------------------------- #
+
+# ⚠️ THE DEFECT THIS TABLE PREVENTS IS THE ONE THE SHIPPED 0.06 WAS: A NUMBER
+# NOBODY COULD SOURCE. 0.06 EUR/kWh is roughly HALF the real Flemish non-energy
+# figure, and because no reader could see what it was made of there was nothing
+# to argue with. Every row below is one line of the Eneco residential card for
+# Flanders, September 2026, INCLUDING 6 % VAT, converted from the c EUR/kWh the
+# card prints to the EUR/kWh this option takes. `price_taxes_eur_kwh`'s default
+# is their sum, and test_price.py section 1b re-adds them and refuses a default
+# that is not exactly that.
+#
+# ⚠️ THIS IS A PER-DSO FIGURE, AND IT IS THE DISTRIBUTION ROW THAT MOVES. Across
+# the eight Fluvius DSOs that row runs 5,28 c EUR/kWh (Midden-Vlaanderen) to
+# 6,70 (West), so the all-in Flemish total runs about 0.117 to 0.131 EUR/kWh.
+# A site outside Antwerpen should type its own total; the other two rows are
+# Flanders-wide and do not move with the DSO.
+#
+# ⚠️ AND THE DEFAULT SITS NEAR THE LOW END OF THAT BAND ON PURPOSE, BECAUSE THE
+# TWO ERROR DIRECTIONS ARE NOT SYMMETRIC. This scalar is a LEVEL component: it
+# cancels exactly in `max - min` and cannot move which hour is cheapest
+# (test_price.py 16b measures that as a family). The one DECISION it reaches is
+# §17's negative-price guard in arbitrage.py, which tests the ABSOLUTE all-in
+# price of the sell hour. A figure set too HIGH carries a genuinely negative
+# hour up above zero, and the add-on exports into paid-for disposal - the exact
+# case §17 exists to refuse. A figure set too LOW only declines a trade that
+# would have paid. So where a default must stand in for eight different DSOs,
+# it belongs at the bottom of the band and not in the middle of it.
+#
+# ⚠️ `energiebijdrage` IS ZERO, AND IT IS A ROW HERE RATHER THAN AN ABSENCE.
+# "Vanaf 1 augustus 2026 bedraagt de energiebijdrage 0 EUR/MWh" - it was merged
+# into the bijzondere accijns. Anyone re-deriving this total from a guide
+# written before that date will find a separate energiebijdrage line and add it
+# on top of an accijns that already contains it. The zero row is here so that
+# the double-count is visible as a decision rather than as an omission.
+FLEMISH_TAXES_COMPONENTS_EUR_KWH = (
+    ("Fluvius distribution, Antwerpen", 0.0535),
+    ("Bijzondere accijns, 'Alle verbruik' - no volume bands", 0.04876),
+    ("Bijdrage groene stroom en WKK Vlaanderen", 0.0151),
+    ("Energiebijdrage - 0 EUR/MWh since 2026-08-01, inside the accijns", 0.0),
+)
+
+# ⚠️ TARIFF-18, AND IT IS NOT HOUSEKEEPING - IT DECIDES WHICH CONFIGS START.
+# TARIFF-17's rung in validate.py refuses a site that sets `price_taxes_profile`
+# AND leaves `price_taxes_eur_kwh` at something other than the shipped default,
+# because the table wins and the scalar would decide nothing. It compares
+# against the DEFAULT rather than against presence, because the Supervisor sets
+# `App.options = deepmerge(config.yaml defaults, stored options)` and a saved
+# blob therefore carries every schema key whether the operator typed it or not
+# (measured: the reference install's export is 70 of 71 keys - CHANGELOG 0.9.0,
+# `tools/supervisor_selfapi_probe.py` §D).
+#
+# So moving the default turns a previously ACCEPTED configuration into
+# `SystemExit(78)`. A site that stored 0.06 - which is every install that has
+# ever saved its configuration - and that also carries a taxes table would stop
+# starting on the upgrade, over a number it never typed and that decides
+# nothing. That refusal would be TRUE and USELESS: the rung's subject is a
+# number the OPERATOR typed, and a superseded shipped default is not one. It
+# still reads as "untouched" here, and the rung's sentence names both figures.
+SUPERSEDED_TAXES_DEFAULTS_EUR_KWH = (0.06,)     # TARIFF-02 .. TARIFF-17
+
+
 # ⚠️ CFG-03, AND HOW THIS TICKET AVOIDS WIDENING IT. Option defaults in this
 # add-on already live in three places - config.yaml, main.py's `o.get(k, X)`
 # fallbacks, and a dataclass default - held apart only by a tripwire in
@@ -836,7 +899,9 @@ def plan_is_provisional(read: PriceRead) -> bool:
 PRICE_OPTION_DEFAULTS = {
     "price_provider": "off",
     "price_markup_eur_kwh": 0.03,      # §14 tariffs.energy_price.markup_eur_kwh
-    "price_taxes_eur_kwh": 0.06,       # §14 tariffs.energy_price.taxes_eur_kwh
+    # TARIFF-18: the sum of FLEMISH_TAXES_COMPONENTS_EUR_KWH above, to the
+    # card's own last digit. §14 tariffs.energy_price.taxes_eur_kwh.
+    "price_taxes_eur_kwh": 0.11736,
     "export_price_eur_kwh": 0.04,      # §14 tariffs.export_price_eur_kwh (AC4)
     "price_csv_path": "/share/goodwe_prices.csv",
     "price_feed_url": "",
@@ -870,6 +935,20 @@ PRICE_OPTION_DEFAULTS = {
     # `static_profile` precedent exactly, and here for the same CFG-03 reason:
     # this dict is the ONE in-code mirror of config.yaml.
     "price_formula": "",
+    # TARIFF-16. The INJECTION leg, in `price_formula`'s OWN grammar and read
+    # by `custom_formula.parse_export_formula()` - the same parser with its
+    # option name as an argument, so a second unit table and a second unknown-
+    # key rule do not exist to diverge. "" is unset and the scalar
+    # `export_price_eur_kwh` above decides, which is every site today.
+    #
+    # ⚠️ IT IS IN FRAMEWORK_KEYS, for the reason the scalar is: a CONSUMPTION
+    # plugin that could read an injection curve could fold it into a
+    # consumption price, and nothing downstream could tell.
+    #
+    # ⚠️ AND IT LIVES HERE RATHER THAN IN custom_formula.py FOR CFG-03's SAKE,
+    # exactly as `price_formula` and `price_taxes_profile` do: this dict is the
+    # ONE in-code mirror of config.yaml.
+    "price_export_formula": "",
     # OPT-04. §10.1 priority 3, and §14's `optimizer.cycle_cost_threshold_eur`.
     #
     # ⚠️ THEY LIVE HERE FOR CFG-03's SAKE, exactly as `static_profile` does, and
@@ -902,6 +981,13 @@ FRAMEWORK_KEYS = frozenset({
     # derived from this set, so `code_leaks()` refuses a plugin that names it
     # without anything else being edited.
     "price_taxes_profile",
+    # TARIFF-16. The hour-varying spelling of `export_price_eur_kwh`, and it
+    # belongs here for the same reason the scalar does: a plugin that could
+    # read an INJECTION curve could fold it into the CONSUMPTION series it
+    # emits, and `assemble()` has no way to notice a component that arrived
+    # inside a RawPoint. `BANNED_IN_PLUGIN_CODE` is derived from this set, so
+    # `code_leaks()` refuses a plugin that names it with nothing else edited.
+    EXPORT_FORMULA_OPTION,
 })
 
 
@@ -1015,28 +1101,82 @@ def export_price_eur_kwh(opts: dict) -> float:
     consumption is at 6% - so it is a second per-contract formula, not a second
     copy of the first.
 
-    ⚠️ TARIFF-15 LANDED THE EVALUATOR AND DID NOT LAND THIS CURVE, and the
-    difference is the point rather than an omission. `custom_formula` can now
-    express `B x index + A` exactly - it is what it exists for - but it is a
-    CONSUMPTION provider: it declares {ENERGY, MARKUP}, the framework adds the
-    consumption taxes, and an injection leg carries its OWN coefficients
-    (Eneco: 0,102 consumption against 0,100 injection) and its own VAT
-    treatment (injection is exempt; consumption is at 6%). Pointing this
-    scalar at that machinery would mean pricing an injection curve with a
-    consumption card, which is the wrong-card defect the card self-check
-    exists to refuse. So until the injection card lands this scalar remains a
-    SIMPLIFICATION an operator enters by hand - an average of what they are
-    actually paid - and not a reflection of the market. When it does land, an
-    injection curve gets a `PriceProvider` of its own and this scalar becomes
-    its FIXED-product default; the seam is already the right shape for that.
+    ⚠️ TARIFF-16 LANDED THE INJECTION LEG, AND THIS FUNCTION IS UNCHANGED. The
+    curve lives in `price_export_formula` and is read by `export_formula()`
+    below; this reader still answers the FLAT injection price, still from one
+    option, still with no formula anywhere in its arithmetic. That is the
+    arrangement this docstring predicted before either existed - "an injection
+    curve gets a `PriceProvider` of its own and this scalar becomes its
+    FIXED-product default" - and it is why a site with a flat injection price
+    sees nothing change: `price_export_formula` ships "", `export_price_at()`
+    falls through to this function, and this function's body is byte-identical
+    to the one TARIFF-02 shipped.
 
     ⚠️ It is NOT reachable from a plugin: `export_price_eur_kwh` is in
     FRAMEWORK_KEYS, so a consumption plugin cannot quietly fold an injection
-    price into a consumption price.
+    price into a consumption price. `price_export_formula` is in the same set
+    for the same reason.
+
+    ⚠️ AND NOTHING IN THIS ADD-ON READS EITHER ONE TO TAKE A DECISION.
+    `arbitrage.py` prices the sell side as DISPLACED IMPORT and says so in its
+    own comment; both hours it compares are all-in consumption prices. This
+    reader has no caller under `app/` and neither does `export_price_at()`.
+    They are what an operator is shown and what a future export-aware strategy
+    would call - not a number any trade turns on today.
     """
     return float(price_option(opts, "export_price_eur_kwh"))
 
 
+def export_formula(opts: dict):
+    """The configured `price_export_formula` as a `FormulaSpec`, or None.
+
+    TARIFF-16. Raises `custom_formula.FormulaInvalid` on a malformed leg - and
+    ⚠️ THAT EXCEPTION IS NOT MEANT TO REACH A RUNNING SITE, by the rule
+    `taxes_profile()` states above and `static_profile` established:
+    validate.py parses the same option at STARTUP and refuses to start on it,
+    because a formula that only fails when something reads it is a defect
+    discovered at the worst possible moment and §11.4 makes every price
+    defect quiet.
+
+    ⚠️ THE PARSE IS THE SAME ONE THE CONSUMPTION LEG GETS. There is no second
+    parser, no second unit table and no second resolution rule -
+    `parse_export_formula()` is `parse_price_formula()` with its `option`
+    argument moved, so every refusal an operator can hit on this leg is a
+    refusal that already had checks over it.
+    """
+    return parse_export_formula(price_option(opts, EXPORT_FORMULA_OPTION))
+
+
+def export_price_at(opts: dict, index_eur_per_mwh: float) -> float:
+    """What the site is PAID for one exported kWh at one index value, EUR/kWh.
+
+    THE SEAM, AND ITS HONEST SCOPE. This is the one function a future
+    export-aware strategy calls, and it has NO CALLER UNDER `app/` today -
+    stated here rather than implied, because the add-on takes no decision on an
+    injection price (see `export_price_eur_kwh()` above and `arbitrage.py`'s
+    accounting-basis comment). What it buys now is that OPT-06 and anything
+    after it inherit a shape the market fits, instead of a scalar that cannot
+    hold its own factor, a negative offset, or a VAT rate different from the
+    consumption leg's.
+
+    ⚠️ THE FLAT PATH IS THE FALLTHROUGH AND IT IGNORES THE INDEX, which is
+    CORRECT rather than a simplification: a site with a flat injection price is
+    paid the same for every kWh whatever the market did, and that is what the
+    scalar means. With `price_export_formula` empty - every site today - this
+    returns exactly `export_price_eur_kwh(opts)` for every index.
+
+    ⚠️ A NEGATIVE ANSWER IS A REAL ANSWER. Eneco's `0,1 x BELPEX-H - 1,188` is
+    below zero for any BELPEX-H under 11,88 EUR/MWh, which is the middle of a
+    sunny day and precisely when a PV household exports. Nothing here floors
+    it: a caller that silently clamped it to zero would hide the hours in which
+    exporting COSTS money, which is the one thing an injection price is for.
+    """
+    spec = export_formula(opts)
+    if spec is None:
+        return export_price_eur_kwh(opts)
+    return price_eur_kwh(spec, index_eur_per_mwh)
+
+
 def taxes_profile(opts: dict):
     """The configured `price_taxes_profile` as a period table, or None.
 
@@ -1174,8 +1314,8 @@ def code_leaks(cls) -> list:
         src = dedent(inspect.getsource(cls))
         tree = ast.parse(src)
     except (OSError, TypeError, IndentationError, SyntaxError) as e:
-        _LOG.warning("could not read %s's source for the framework-key scan "
-                     "(%s); the double-counting guard is NOT enforced for it",
+        _LOG.warning("Could not read the code of price source %s (%s), so its "
+                     "double-counting check is skipped.",
                      getattr(cls, "id", cls), e)
         return []
     for node in ast.walk(tree):
@@ -1313,9 +1453,8 @@ def _validate_raw(points, caps):
         if abs(p.eur_per_kwh) > MAX_PLAUSIBLE_EUR_KWH:
             raise SourceUnavailable(
                 f"point at {p.start.isoformat()} is {p.eur_per_kwh} EUR/kWh, "
-                f"beyond +-{MAX_PLAUSIBLE_EUR_KWH} - the usual cause is a feed "
-                f"in EUR/MWh being read as EUR/kWh, which is a factor of 1000 "
-                f"and would make every hour look like an emergency")
+                f"beyond +-{MAX_PLAUSIBLE_EUR_KWH}, so the feed is probably in "
+                f"EUR/MWh")
         u = p.start.astimezone(timezone.utc)
         if seen is not None and u <= seen:
             raise SourceUnavailable(
@@ -1568,25 +1707,19 @@ def _points_from_columnar_json(body, expect_unit, scale,
     if len(times) != len(prices):
         raise SourceUnavailable(
             f"{COLUMNAR_TIME_KEY} has {len(times)} entries and "
-            f"{COLUMNAR_PRICE_KEY} has {len(prices)}; refusing to zip them. "
-            f"The short array would truncate the series silently, and a price "
-            f"series missing its last hours is one missing the evening peak - "
-            f"traded on as if complete, where no data at all would have "
-            f"switched arbitrage off (§11.4)")
+            f"{COLUMNAR_PRICE_KEY} has {len(prices)}, so the feed is cut short "
+            f"and none of it is used")
     unit = _columnar_unit(doc.get(COLUMNAR_UNIT_KEY, ""))
     if unit != _columnar_unit(expect_unit):
         raise SourceUnavailable(
             f"the feed reports {doc.get(COLUMNAR_UNIT_KEY)!r}, not "
-            f"{expect_unit!r}. This provider converts with a fixed factor of "
-            f"{scale}, so a changed unit is a factor of 1000 on every price "
-            f"with nothing downstream able to notice it")
+            f"{expect_unit!r}, so its prices cannot be converted")
     if doc.get("deprecated"):
         # Not a refusal: today's prices are still prices. But §11.4 makes a
         # dead feed look exactly like a quiet one, so the warning that the
         # source is going away has to be emitted while it still works.
-        _LOG.warning("the price feed reports deprecated=%r; it still answers, "
-                     "but this endpoint is scheduled to stop",
-                     doc.get("deprecated"))
+        _LOG.warning("The price feed says it will stop (deprecated=%r), "
+                     "though it still answers for now.", doc.get("deprecated"))
     out = []
     dropped = []
     for i, (t, v) in enumerate(zip(times, prices)):
@@ -1605,9 +1738,8 @@ def _points_from_columnar_json(body, expect_unit, scale,
         out.append(RawPoint(start=start, eur_per_kwh=float(v) * scale,
                             provisional=bool(provisional_default)))
     if dropped:
-        _LOG.warning("the feed published no price for %d of %d instants "
-                     "(index %s); those instants are left OUT of the series, "
-                     "never zero-filled - a missing hour is not a free hour",
+        _LOG.warning("The price feed gave no price for %d of %d times (index "
+                     "%s). Those times are left out, not counted as free.",
                      len(dropped), len(times),
                      ", ".join(str(i) for i in dropped[:5])
                      + (", ..." if len(dropped) > 5 else ""))
@@ -1656,16 +1788,16 @@ def dayahead_feed_url(plugin_id, opts, since, until, base, bzn) -> str:
     override = str(opts.get("price_feed_url") or "").strip()
     if override:
         _LOG.warning(
-            "price_feed_url is set, so %s is requesting %s exactly as "
-            "given and is adding NO date range to it. The public feed "
-            "answers a single Brussels day to a request that names no "
-            "range, and every hour past that day is then carried forward "
-            "from yesterday's profile and flagged provisional - §8.3 "
-            "drops provisional hours from the trade set, so arbitrage "
-            "would never see tomorrow as firm. Clear price_feed_url to "
-            "let this plugin ask for the %s..%s it was given.",
+            "price_feed_url is set, so %s asks for %s as given, and "
+            "tomorrow's prices may stay provisional. Clear it to ask for %s "
+            "to %s.",
             plugin_id, override, *(d.isoformat()
                                    for d in brussels_date_range(since, until)))
+        _LOG.debug(
+            "The public feed answers one Brussels day to a request that names "
+            "no range. Every later hour is then copied from yesterday and "
+            "marked provisional, and §8.3 leaves provisional hours out of "
+            "trading.")
         return override
     first, last = brussels_date_range(since, until)
     return dated_feed_url(base, bzn=bzn, start=first.isoformat(),
@@ -1871,11 +2003,9 @@ class CustomFormula(PriceProvider):
             raise SourceUnavailable(f"price_formula: {e}")
         if spec is None:
             raise SourceUnavailable(
-                "price_provider is 'custom_formula' but price_formula is "
-                "empty, so there are no coefficients to price anything with. "
-                "validate.py refuses this configuration at startup; reaching "
-                "it here means the options blob changed under a running "
-                "add-on")
+                "“Dynamic price source” (price_provider) is 'custom_formula', "
+                "but “Your own tariff formula” (price_formula) is empty. "
+                "Restart the add-on to check the settings again")
         url = dayahead_feed_url(self.id, opts, since, until,
                                 self.FEED_BASE, self.BZN)
         check_egress(url, self.capabilities())
@@ -1951,8 +2081,8 @@ def _emit_startup_preview(plugin, pid: str, points) -> None:
     try:
         lines = list(plugin.startup_preview(points))
     except Exception as e:                                    # noqa: BLE001
-        _LOG.warning("%s's startup preview raised (%s: %s); prices are "
-                     "unaffected - this is a log line, not a decision",
+        _LOG.warning("%s could not show its start-up preview (%s: %s). Prices "
+                     "are not affected.",
                      pid, type(e).__name__, e)
         return
     for line in lines:
@@ -1999,12 +2129,12 @@ async def load_prices(opts: dict, since: datetime, until: datetime,
         # Not silent, and not a traceback into the 30 s tick. validate.py
         # should have refused this at startup; if the add-on is running with it
         # anyway, the operator is told which key and what is wrong with it.
-        _LOG.error("price_taxes_profile cannot be used (%s: %s), so this fetch "
-                   "has NO tax component to add - it is not falling back to "
-                   "price_taxes_eur_kwh, because a silently different tax "
-                   "basis is the defect this option exists to remove. Fix the "
-                   "table or clear it; validate.py refuses it at startup",
+        _LOG.error("price_taxes_profile cannot be used (%s: %s), so no taxes "
+                   "are added to this price update. Fix the table or clear it.",
                    type(e).__name__, e)
+        _LOG.debug("price_taxes_eur_kwh is not used instead, because a "
+                   "silently different tax basis is the fault this setting "
+                   "exists to remove.")
         return PriceRead.no_data(
             f"price_taxes_profile cannot be used: {e}")
     if table is not None:

goodwe_controller/app/price_history.py

@@ -345,8 +345,8 @@ def _row_of(day: str, points: int, hours: int) -> str:
     whole day to carry, and that is the HOUR figure; the point count says how
     finely it is priced. Neither answers for the other.
     """
-    return (f"{day} ({points} point{'' if points == 1 else 's'} "
-            f"over {hours} h)")
+    return (f"{day} ({points} price{'' if points == 1 else 's'} "
+            f"over {hours} hour{'' if hours == 1 else 's'})")
 
 
 def _bad_rows(rec) -> int:
@@ -437,9 +437,9 @@ class PriceHistory:
             # exactly what this handler says, and a third `ValueError` subclass
             # nobody has thought of is how this defect arrived the first time.
             self.last_error = f"unreadable ({err})"
-            _LOG.warning("price history at %s is %s - starting from empty. "
-                         "§8.3 carry-forward has nothing to carry until the "
-                         "next refresh has written a full day",
+            _LOG.warning("Price history at %s is %s, so it starts empty. "
+                         "Missing hours cannot be filled in until a full day "
+                         "is saved.",
                          self.path, self.last_error)
             return
         found = blob.get("version") if isinstance(blob, dict) else None
@@ -775,8 +775,8 @@ class PriceHistory:
                 f"which is not a PriceProduct. The optimiser switches on that "
                 f"enum, so a record that cannot name one cannot be a series")
         if bad:
-            _LOG.warning("price history: %s in the %s record were dropped; "
-                         "%d point(s) carried forward", bad, want, len(points))
+            _LOG.warning("Price history: %s in the %s record were dropped, "
+                         "and %d points were kept.", bad, want, len(points))
         return PriceRead.series(points, product,
                                 str(rec.get("provider") or "price_history"),
                                 stamp)

goodwe_controller/app/pv.py

@@ -0,0 +1,274 @@
+"""TEL-11/TEL-12 - the site's PV production, read from Home Assistant entities.
+
+WHY THIS IS AN ENTITY AND NOT A REGISTER. This add-on's RS485 bus carries the
+BATTERY inverter it drives. A household's PV inverter is, on nearly every site,
+a different box from a different vendor that reports into Home Assistant
+through its own integration - so the only place a product can read production
+for an arbitrary install is an HA entity. `pv_entities` therefore takes whatever
+`sensor.*` the site's own PV integration provides.
+
+⚠️ AND THERE IS USUALLY MORE THAN ONE OF THEM, WHICH IS TEL-12. TEL-11 shipped
+`pv_entity` as a single string and the owner of the reference site reported
+within minutes of 0.11.0 going live that they have SEVERAL PV inverters and
+could configure one. That is not a property of one house: a multi-string or
+multi-orientation roof routinely carries two or three inverters, each
+publishing its own power sensor. `entities()` below is the roster and `total()`
+is the site figure over it.
+
+⚠️ AND A PARTIAL TOTAL IS WORSE THAN NO TOTAL, WHICH IS THE WHOLE OF TEL-12.
+Three inverters configured, one `unavailable`, and the sum of the other two is A
+SMALLER NUMBER INDISTINGUISHABLE FROM A REAL ONE. Fed into OPT-10's attribution
+that reads as "there was less PV than there was" - which is the "no irradiance"
+conclusion the card exists to TEST rather than to manufacture. So `total()`
+answers `None` the moment ANY configured entity is absent. See the note on
+`total()` for the alternative that was weighed and why it lost.
+
+WHY THE CHANNEL EXISTS AT ALL. OPT-10 measured that 20.5 kWh of surplus left the
+site in 16 days while the pack had room, 12.6 kWh of it with the battery not
+charging at all - and could not say WHY, because PV production is recorded
+NOWHERE. Three causes need three different fixes (no irradiance: nothing to fix;
+a charge-power limit; the optimiser declining to charge - the only software
+defect), and guessing between them is how an optimiser gets tuned to solve a
+cloud problem. This module is the missing measurement and NOTHING ELSE.
+
+⚠️ NOTHING HERE MAY EVER REACH A CONTROL DECISION, AND THAT IS THE CARD'S FIRST
+CONSTRAINT RATHER THAN A STYLE NOTE. The add-on regulates a real battery; adding
+production as a term of the control law would be an unrequested behaviour change
+AND it would destroy the measurement, because the loop would then be reacting to
+the quantity being measured. `tools/tel11_pv_trace.py` is what says the path is
+untouched: it grades a control document that contains none of this material on
+both trees and with `pv_entity` set and unset.
+
+⚠️ ABSENCE IS NEVER ZERO, AND THAT IS THE SECOND CONSTRAINT. Every refusal below
+returns `None` with a REASON, never `0.0`. A PV channel that reported 0 W for a
+dead sensor would manufacture exactly the "there was no surplus to store"
+conclusion the card exists to TEST - and it would do it silently, in a week of
+recorder history nobody would re-derive. `app/hass.py`'s own note on `state()`
+is the same rule one layer down. ⚠️ TEL-12 EXTENDS THAT RULE RATHER THAN
+WEAKENING IT: at a roster of three, "one of them is absent" is an absence of the
+SITE figure, and it publishes as an absence. A partial sum is a second way of
+reporting 0-where-there-was-production, one layer up, and it is refused for the
+same reason.
+
+THE SIGN CONVENTION: POSITIVE IS PRODUCTION, as for `meter_entity` and
+`batt_entity` ("power arriving at the house's AC bus"). TEL-14: a kWh meter or
+power clamp in the PV circuit reads the other way, so `pv_invert_entities`
+flips the sign per entity. See `DECISIONS/TEL-14-pv-sign.md`.
+"""
+
+from .hass import BAD_STATES
+
+# Home Assistant's OWN power units, each as the number of watts one of it is.
+# ⚠️ READ OUT OF HA, NOT LISTED FROM MEMORY: `UnitOfPower` in
+# `homeassistant/const.py` (github.com/home-assistant/core, `dev`, retrieved
+# 2026-09-24) declares mW, W, kW, MW, GW, TW and BTU/h. Every factor here is an
+# exact power of ten, so none of them is a number anybody chose.
+#
+# ⚠️ BTU/h IS IN HA's ENUM AND DELIBERATELY NOT HERE. Its factor (0.293071…)
+# is a measured conversion rather than a decimal shift, no PV integration
+# publishes in it, and a wrong constant in the one channel that exists to
+# attribute a 20.5 kWh shortfall is worse than a refusal an operator can read.
+# It lands in the "not a power unit" refusal below, BY NAME.
+WATTS_PER = {
+    "mW": 0.001,
+    "W": 1.0,
+    "kW": 1000.0,
+    "MW": 1000000.0,
+    "GW": 1000000000.0,
+    "TW": 1000000000000.0,
+}
+
+# What `watts()` answers when there is nothing to report. ⚠️ THE REASON IS PART
+# OF THE RETURN VALUE, not a log line: it is what the status page prints, and an
+# absence whose cause is invisible sends an operator to look at the wrong box.
+UNIT_KEY = "unit_of_measurement"
+
+
+def watts(state: dict | None) -> tuple:
+    """`(watts, why)` from a Home Assistant state object.
+
+    `watts` is `None` whenever there is no reading - and `why` then says which
+    of the five refusals it was, in words an operator can act on. On a good read
+    `why` is the unit the value was read in, because "1234 W" and "1234, unit
+    unknown" are different claims and the page has to be able to make the first.
+
+    ⚠️ THE UNIT IS READ OFF THE ENTITY AND NOT ASSUMED, AND THERE IS NO
+    MAGNITUDE HEURISTIC. `read_inputs()` guesses kW-or-W for
+    `peak_forecast_entity` with `abs(raw) < 50`, which is safe there because
+    nobody's quarter-hour demand forecast is 50 W. It is NOT safe here: 30 W of
+    real production at dusk is an ordinary reading, and that heuristic would
+    publish it as 30 kW - a fabricated number, in the channel whose entire
+    purpose is to be believed a week later. A sensor whose unit this cannot read
+    is REFUSED rather than guessed at.
+    """
+    if state is None:
+        # `hass.state()` answers None for a non-existent entity, a 404 and a
+        # transport failure alike. All three are "no reading", and HA does not
+        # consider a non-existent entity an error - see `hass.state()`.
+        return None, "no state (entity missing, or the read failed)"
+    raw = str(state.get("state", "")).strip()
+    if raw.lower() in BAD_STATES:
+        # ⚠️ THE SAME LIST `hass.number()` REFUSES ON, IMPORTED RATHER THAN
+        # RESPELLED. A second copy of it is how one path starts treating
+        # `unavailable` as a number the other one rejects.
+        return None, f"entity is {raw or 'empty'}"
+    try:
+        value = float(raw)
+    except ValueError:
+        return None, f"state {raw!r} is not numeric"
+    unit = str((state.get("attributes") or {}).get(UNIT_KEY) or "").strip()
+    if not unit:
+        return None, ("no unit_of_measurement on the entity - it cannot be "
+                      "read in watts")
+    if unit not in WATTS_PER:
+        return None, (f"unit {unit!r} is not one of "
+                      f"{', '.join(WATTS_PER)} - it cannot be read in watts")
+    return value * WATTS_PER[unit], unit
+
+
+# --- TEL-12: the ROSTER, and the SITE figure over it --------------------------
+
+def entities(opts: dict) -> tuple:
+    """Every PV entity this configuration names, in configured order. TEL-12.
+
+    ⚠️ ONE ANSWER TO "WHICH ENTITIES ARE THE PV CHANNEL", and it is the answer
+    BOTH sides read. `Controller.pv_roster` is this call and
+    `mqtt.optional_keys()` is `bool()` of this call, so the thing that decides
+    whether the row is ANNOUNCED, the thing that decides whether it is READ and
+    the thing that decides HOW MANY entities are summed cannot disagree. TEL-11
+    already had that discipline for one entity and spelled the predicate TWICE
+    - `str(opts.get("pv_entity") or "").strip()` in `main.py` and again in
+    `mqtt.py`. Two spellings of one predicate is how an entity gets announced
+    that nothing feeds; a roster makes it how a SUM gets taken over a different
+    list from the one that was announced. It is one function now.
+
+    ⚠️ `pv_entities` REPLACES `pv_entity` RATHER THAN EXTENDING IT, and that is
+    CFG-04's shipped precedent (`inverters:` replaces the six flat keys) applied
+    to the only upgrade path that matters. The install this card exists for HAS
+    `pv_entity` set, to inverter A. Opening the Configuration tab, the natural
+    action is to put ALL the inverters in the new repeatable field - and under a
+    UNION rule that double-counts A unless the operator also remembers to clear
+    the old key. A doubled total is the same defect as a partial one in the
+    other direction, in the one channel that exists to be believed a week later.
+    Under REPLACE the effective roster is exactly what one key says, and no
+    arithmetic depends on a de-duplication rule the operator has to know about.
+    ⚠️ `Controller.checks()` says WHICH key is in use whenever both are set, so
+    the replacement is stated on the page rather than being silent.
+
+    ⚠️ AND IT DE-DUPLICATES WITHIN THE LIST, ORDER PRESERVED. A site cannot have
+    two sensors with one entity_id, so a repeated id in the list is never a
+    second inverter - it is a typo that would DOUBLE that inverter's production
+    in the total. `dict.fromkeys` is the order-preserving spelling.
+    """
+    listed = [e for e in (str(x or "").strip()
+                          for x in (opts.get("pv_entities") or [])) if e]
+    if listed:
+        return tuple(dict.fromkeys(listed))
+    one = str(opts.get("pv_entity") or "").strip()
+    return (one,) if one else ()
+
+
+def entity_is_ignored(opts: dict) -> bool:
+    """Is a set `pv_entity` being REPLACED by a set `pv_entities`? TEL-12.
+
+    ⚠️ HERE RATHER THAN IN `Controller.checks()`, for the reason `entities()`
+    exists: the rule and the sentence that reports the rule must not be two
+    readings of the options. This is the negative half of `entities()`' first
+    branch and it is spelled once, beside it, where an edit to one is in front
+    of whoever is editing the other.
+    """
+    return bool(str(opts.get("pv_entity") or "").strip()
+                and [x for x in (opts.get("pv_entities") or [])
+                     if str(x or "").strip()])
+
+
+def inverted(opts: dict) -> frozenset:
+    """The entity ids `pv_invert_entities` flips. TEL-14."""
+    return frozenset(e for e in (str(x or "").strip()
+                                 for x in (opts.get("pv_invert_entities") or []))
+                     if e)
+
+
+def stray_inverts(opts: dict) -> list:
+    """`pv_invert_entities` entries naming no entity in the roster - a typo
+    that would otherwise leave a sign unflipped with nothing said. TEL-14."""
+    roster = set(entities(opts))
+    return sorted(e for e in inverted(opts) if e not in roster)
+
+
+# TEL-14: a reading below this is not standby draw. A correctly signed meter in
+# the PV circuit reads a few watts NEGATIVE at night (the owner's: 13 W); -50 W
+# clears that with room for a couple of such devices on one entity, while a
+# reversed sensor in daylight reads hundreds to thousands of watts below zero.
+NEGATIVE_W = -50.0
+
+
+def total(readings, flip=frozenset()) -> tuple:
+    """`(watts, why, parts)` - the SITE's production, or an ABSENCE. TEL-12.
+
+    `readings` is `[(entity_id, state), ...]` in `entities()` order, one entry
+    per configured entity, each `state` shaped as `hass.state()` returns.
+
+    `parts` is `[(entity_id, watts, why), ...]` - EVERY entity's own answer from
+    `watts()`, kept because the operator surfaces have to be able to name which
+    sensor is missing. `watts` is the sum when every entity answered, and `None`
+    otherwise; `why` always says which of those it was, in words a status page
+    can print.
+
+    ⚠️ ONE OR MORE ABSENT -> THE TOTAL IS ABSENT. NOT THE PARTIAL SUM. This is
+    the decision the card turns on and it was taken deliberately against the
+    alternative, which was to publish the partial sum ALONGSIDE a count of how
+    many entities contributed. Both are defensible; this one wins on the ONE
+    question that matters, which is who reads the number and when:
+
+      * the MQTT row is read back COLD, a week later, by OPT-10's attribution
+        and by whatever plots `sensor.goodwe_pv_power` over that week. A partial
+        sum there is a smaller number indistinguishable from a real one, and the
+        count that would have qualified it lives in a SECOND entity with its own
+        history - so believing the total requires joining two recorder series by
+        timestamp to find out which samples to distrust. Nobody re-derives that,
+        which is the same "nobody will re-derive it" TEL-11's note names. And it
+        is worse than a gap in exactly the direction that matters: a gap makes
+        the attribution say "I do not know", a partial sum makes it say "there
+        was less sun than there was".
+      * the STATUS PAGE is read LIVE, by a human, who wants the diagnostic. So
+        the partial information is not thrown away - `Controller.checks()` names
+        every entity that DID report, with its watts, and every one that did
+        not, with its reason, in a row that states plainly that there is no site
+        total. Different reader, different instant, different rule.
+
+    A count published beside the total would also carry no information in the
+    state this function actually admits: the total is published ONLY when every
+    entity contributed, so the count would be the constant `len(parts)`.
+
+    ⚠️ AND `0 W` IS STILL A READING AT EVERY ROSTER SIZE - the test is
+    `watts is None`, never falsiness. An inverter honestly reporting 0 W at dusk
+    beside two that are producing must give the SUM of the three, not blank the
+    site: shading, a tripped string and nightfall are all real 0s, and a roster
+    that went to `unknown` whenever one member read zero would report an absence
+    on every clear evening and defeat the channel from the other end.
+
+    ⚠️ TEL-14: `flip` is `inverted(opts)`; each member's sign is applied HERE,
+    before the sum, so every surface reads the corrected figure. `0.0 - w`
+    rather than `-w`, so a flipped 0 W is `0.0` and never `-0.0` on the wire.
+    """
+    parts = [(ent, w if w is None or ent not in flip else 0.0 - w, why)
+             for ent, (w, why) in ((e, watts(st)) for e, st in readings)]
+    if not parts:
+        # No roster. `Controller` does not call this in that state - the gate is
+        # `pv_roster` - but a reader of `parts` should never have to wonder.
+        return None, "not configured", parts
+    if len(parts) == 1:
+        # ⚠️ AT ONE ENTITY THIS IS `watts()` AND NOTHING ELSE: the same value
+        # and the SAME `why` string, passed through rather than re-composed, so
+        # 0.11.0's single-entity surfaces are byte-identical rather than
+        # similar. `tools/tel11_pv_trace.py` grades that identity across trees.
+        return parts[0][1], parts[0][2], parts
+    missing = [(ent, why) for ent, w, why in parts if w is None]
+    if missing:
+        return None, (
+            f"only {len(parts) - len(missing)} of {len(parts)} entities are "
+            f"reporting and a partial sum would understate production: "
+            + "; ".join(f"{ent} - {why}" for ent, why in missing)), parts
+    return (sum(w for _e, w, _y in parts),
+            f"{len(parts)} entities", parts)

goodwe_controller/app/selfconfig.py

@@ -381,8 +381,8 @@ async def save(selfcfg: SelfConfig, proposed: dict, expect: str, *,
     """
     problems = await problems_for(proposed, hass)
     if problems:
-        _LOG.warning("panel REFUSED to save: %d configuration problem(s); "
-                     "nothing written. First: %s", len(problems), problems[0])
+        _LOG.warning("The settings page did not save, because of %d "
+                     "problems. The first: %s", len(problems), problems[0])
         raise SaveRefused("invalid", problems=problems)
 
     info = await selfcfg.info()
@@ -390,8 +390,8 @@ async def save(selfcfg: SelfConfig, proposed: dict, expect: str, *,
     actual = fingerprint(stored)
     if actual != expect:
         changed = changed_keys(stored, proposed)
-        _LOG.warning("panel REFUSED to save: the stored options changed "
-                     "underneath this page (keys: %s); nothing written",
+        _LOG.warning("The settings page did not save, because the settings "
+                     "changed while it was open (keys: %s).",
                      ", ".join(changed) or "none this page also edited")
         raise SaveRefused("stale", changed=changed, stored=stored)
 

goodwe_controller/app/shadow.py

@@ -0,0 +1,506 @@
+"""SAFETY-10 - shadow mode: the whole decision path, and no command.
+
+WHAT DEFECT THIS PREVENTS
+=========================
+Not one defect - the CLASS of them. Every optimiser fault this repository has
+found was invisible from outside while it was happening, and each one was paid
+for at the meter before anybody could see it:
+
+  * SAFETY-45  arbitrage against a binding `peak_cap_w` ran 28 charge onsets an
+               hour, the grid swinging -455 .. +3200 W, and put a billed
+               quarter 59 W over the cap;
+  * TARIFF-14  the price lookup answered for the wrong quarter-hour 45 minutes
+               in every 60, and traded on it;
+  * SAFETY-46  the SoC ceiling churns 598 Wh to gain 310 Wh, no hysteresis.
+
+There was no way to WATCH what the optimiser would do without letting it do it.
+A commissioning engineer could arm arbitrage and find out, or not arm it and
+learn nothing. Shadow mode is the third option: strategies, arbiter, clamps and
+guards all run, the decision is recorded with its reason, and NOTHING THE
+CONTROLLER DECIDES REACHES THE INVERTER.
+
+⚠️ AND OF THOSE THREE, A SHADOW RUN CAN SHOW YOU EXACTLY ONE - SEE THE NEXT
+   SECTION. This header used to name SAFETY-45's limit cycle as the example
+   of what shadow mode surfaces. That was false, and SAFETY-47 measured it.
+
+⚠️ WHAT A SHADOW RUN CAN AND CANNOT SHOW  (SAFETY-47)
+=====================================================
+SHADOW MODE CANNOT SURFACE A CLOSED-LOOP DEFECT. Not badly, not partially -
+NOT AT ALL, and by the same construction that makes it safe. The actuator is
+held at WIRE_W and the carried command is re-seeded to WIRE_W, so every
+MEASURED input - the meter, the quarter accumulator behind it, the battery
+power, the state of charge - describes a plant that DID NOT RESPOND. A
+closed-loop defect is by definition one whose stimulus is the plant's response
+to the controller. No response, no stimulus, no defect to see.
+
+That is not a gap to be closed later. Feeding the guards a simulated plant
+instead is what SAFETY-10 §4 refuses for the sign watchdogs, for a reason that
+applies to all of this: a controller reacting to a plant that does not exist
+drifts further from reality every tick, and three cycles in its numbers
+describe nothing. THE CLOSED-LOOP ANSWER COMES FROM A CLOSED-LOOP RIG
+(TEST-23 stage 3) OR FROM A LIVE RUN. There is no third place.
+
+So, of the three defects above, measured on that rig at `peak_cap_w` 1500 /
+house 1200 / `max_w` 2000, one hour at a 5 s cycle:
+
+  * SAFETY-45's limit cycle    NOT VISIBLE. Live: 28 charge onsets, the grid
+                               swinging -455.5 .. +3200.0 W, the guard engaged
+                               on 410 of 720 cycles. Shadow, same hour, same
+                               code: 1 onset, the grid flat at the 1200 W
+                               house, the guard engaged on 0 of 720. Every
+                               term of `wanted = batt_w + excess` is measured.
+  * SAFETY-46's SoC churn      NOT VISIBLE. The SoC moves 0.000000000 pp in a
+                               shadow run, because it is the pack's integral of
+                               what the pack was commanded and the pack was
+                               commanded 0 W. No SoC limit can be REACHED in a
+                               shadow run; the ones already crossed when it
+                               started are reported, and that is all.
+  * TARIFF-14's wrong quarter  VISIBLE, and it is the one. The price lookup's
+                               inputs are the CLOCK and the PRICE SERIES, and
+                               neither is a function of what the battery did.
+                               Measured: which hour the strategy picked, its
+                               price and the spread it cleared are identical
+                               live and shadow on 720 of 720 charging cycles,
+                               AT A BINDING CAP.
+
+⚠️ THE EXEMPTION THAT USED TO BE HERE WAS TRUE UNTIL SAFETY-45 MERGED. This
+module, DOCS.md and DECISIONS/SAFETY-10-shadow-mode.md all said "the strategies
+are unaffected - they ask for a fixed power from inputs that do not depend on
+what the battery did". SAFETY-45 made the buy leg `min(asked, headroom)` with
+
+    headroom = (900 / remaining) x (ceiling - projected)
+
+and `projected` reads the OPEN QUARTER'S ACCUMULATOR - the meter - which is a
+function of what the battery did earlier in that same quarter. The strategy
+became closed-loop the day that landed. What survives of the exemption, and
+only this:
+
+    WHICH hour a strategy picks, and WHY, are unaffected.
+    HOW HARD it trades is not.
+
+⚠️ AND THE SIZE A SHADOW RUN RECORDS IS THE RIGHT ANSWER TO A QUESTION NOBODY
+   ASKED. `900/remaining` is correct arithmetic for a meter that is genuinely
+under the ceiling - and in shadow the meter genuinely IS under it, because the
+battery is not charging. So the number is not a bug; it is an answer computed
+for a plant that did not exist. Measured on the same rig, shipped code:
+
+    cap / house      live commanded      shadow recorded      over
+    1500 / 1200         -302.4 W            -2000.0 W         6.61x
+    3500 / 3000         -502.6 W            -2000.0 W         3.98x
+    3500 / 2000        -1502.6 W            -2000.0 W         1.33x
+    3500 / 1800        -1702.6 W            -2000.0 W         1.17x
+   15000 /  350        -2000.0 W            -2000.0 W         1.00x
+
+The last row is the fixture SAFETY-10's own evidence was taken on, which is why
+nothing reported this. `words()` carries the caveat rather than a re-computed
+number, and `DECISIONS/SAFETY-47-what-a-shadow-run-can-show.md` §3 records the
+three alternatives that were rejected and why.
+
+⚠️ "REACHES NOTHING" IS NOT "WRITES NOTHING", AND THE DIFFERENCE IS THE WHOLE
+   SAFETY ARGUMENT
+=======================================================================
+The inverter holds its last command FOREVER - it has no meter timeout
+(HANDOVER.md §6), and firmware/goodwe-master.yaml's header records what that
+cost when a controller stopped refreshing: Illusmart went silent mid-command
+and the inverter held +5000 W for 113 s. main.py's own header carries the same
+measurement. So a shadow mode that
+simply stopped writing would leave whatever was standing when it was switched
+on standing for as long as it was left on. That is the exact failure this
+repository keeps finding - LOOKS HEALTHY BUT IS INERT - with the status page
+calmly reporting that nothing is being commanded.
+
+So shadow mode does write, and it writes ONE number:
+
+    the actuator is held at WIRE_W (0.0 W), refreshed on the ordinary
+    heartbeat, by the ordinary single writer.
+
+That is a DEFINED, SAFE actuator state, it is the same state the operator's
+stop button reaches, and it honours the contract firmware/goodwe-master.yaml
+§"CONTRACT CHANGE" imposes on us - HA must rewrite the setpoint every ~10 s or
+the ESP32's 30 s stale-input watchdog cannot tell "steady" from "dead". Going
+silent would put that board into a tripped-watchdog state for the whole shadow
+run, which is an ALARM being used as a MODE: the operator who learns that
+`wd_tripped` is normal during shadow runs is the operator who ignores it when
+the add-on has actually died.
+
+⚠️ AND IT IS NOT A SECOND WRITE PATH. SAFETY-28's rule is one actuator, one
+writer. Shadow mode files no claim, owns no transport and calls nothing in
+hass.py. It is a SUBSTITUTION inside `Controller._write_unit()` - the single
+choke point every write in this add-on already goes through - in exactly the
+form the three substitutions above it take (non-finite -> 0 W, unauthorised ->
+0 W, clamped -> the rating). It is the LAST of them, so SAFETY-28's
+authorisation gate and SAFETY-03's clamp still grade the number the decision
+path actually produced, and a shadow run therefore records that the clamp WOULD
+have engaged.
+
+THE DEFAULT, AND WHY IT IS NOT A PLAIN `true`  (§ the ticket's own warning)
+==========================================================================
+The card is titled "default-on". Taken literally - `shadow_mode: true` in
+`config.yaml`'s `options:` block - it is the worst change in this repository's
+history. Home Assistant's Supervisor composes an add-on's effective options as
+`{**config.yaml defaults, **the stored user options}`, so a NEW key with a new
+default reaches EVERY install on the next update, including the one regulating
+a real battery in the author's house today. Literal default-on silently stops
+an existing install from controlling, and the only symptom is a battery that
+has stopped doing anything.
+
+There is no mechanism in the add-on options system that lets one key default
+differently for a new install and an existing one: `options:` IS the default,
+and there is exactly one of it. So "default-on for new" has to be expressed as
+a value the add-on RESOLVES, not as a constant the Supervisor merges.
+
+Hence three values rather than two, defaulting to `auto`:
+
+    off    never shadow. The controller commands the battery.
+    on     always shadow, whatever the start/stop button says.
+    auto   shadow WHILE CONTROL IS STOPPED; live once it is started.
+
+`auto` is default-on for a new install and a no-op for an existing one, and it
+is that without any persisted marker, any migration, and any guess:
+
+  * a FRESH install ships `auto_start: false` and has no stored `auto` key, so
+    it comes up stopped -> shadow. It observes a day of decisions before it is
+    ever allowed to command anything. That is the card's intent, delivered.
+  * an install that is CONTROLLING - `auto_start: true`, or the operator has
+    pressed *Start / stop control* and the store carries `auto: true` - is
+    started, so `auto` resolves to LIVE and its behaviour does not change by
+    one watt.
+  * an install that is STOPPED keeps its actuator at 0 W exactly as before -
+    the same number, from the same writer, on the same heartbeat - and gains
+    the recording. The only thing that changes for it is what the status page
+    and the action log SAY.
+
+⚠️ AND `auto` MEANS THE START BUTTON LEAVES SHADOW MODE. That is deliberate:
+under `auto` the button reads "Start / stop control" and pressing Start is the
+operator saying "control the battery". An operator who wants the decisions
+recorded WHILE the loop runs sets `shadow_mode: on` explicitly - that is the
+configuration this card exists to make possible, and it is the one that cannot
+be reached by accident.
+
+⚠️ AN UNRECOGNISED VALUE RESOLVES TO SHADOW, NOT TO LIVE. `validate.py` refuses
+it at startup so this is not meant to be reachable, but the fail-safe direction
+for "the operator's intent is unreadable" is the one that does not move energy.
+
+THE FAILSAFES, ONE BY ONE (the card asks for each to be decided and recorded)
+============================================================================
+| failsafe                       | in shadow mode                            |
+|--------------------------------|-------------------------------------------|
+| SAFETY-02/30 sign watchdogs    | INERT, and by construction rather than by |
+| (per-unit and site)            | a special case. They grade                |
+|                                | `Inverter.standing_w()` - what this       |
+|                                | controller has standing on the wire - and |
+|                                | shadow mode holds that at 0 W. A 0 W      |
+|                                | command cannot oppose a meter, so the     |
+|                                | detector never arms. ⚠️ THIS IS THE ONE   |
+|                                | THAT HAD TO BE GOT RIGHT: fed the SHADOW  |
+|                                | decision instead, every shadow run would  |
+|                                | latch a trip within `sign_disagree_s` -   |
+|                                | the decision opposes a meter that never   |
+|                                | saw it - and that latch SURVIVES INTO     |
+|                                | LIVE OPERATION and a restart. Shadow mode |
+|                                | would manufacture the failsafe it is      |
+|                                | meant to help debug.                      |
+| SAFETY-03 clamp                | OBSERVES. It runs on the number the       |
+|                                | decision path produced, `clamp_last` is   |
+|                                | set and every engagement goes to the      |
+|                                | action log, because "it would have hit    |
+|                                | the rating" is part of what a shadow run  |
+|                                | is for. It changes no command: the value  |
+|                                | it narrows is replaced by 0 W below it.   |
+| SAFETY-28 write authorisation  | OBSERVES, for the same reason and in the  |
+|                                | same place - above the substitution, so   |
+|                                | it still asks who chose the number.       |
+| SAFETY-18 meter freeze         | OBSERVES, unchanged. It takes no action   |
+|                                | in live operation either; it grades the   |
+|                                | resolved intent against a meter that has  |
+|                                | stopped moving, and both halves are as    |
+|                                | true in shadow as out of it.              |
+| SAFETY-07/24/25 peak guard     | OBSERVES, AND SEES ONLY THE HOUSE. It is  |
+|                                | level-triggered and unlatched and it files|
+|                                | its claim as usual, so the recorded       |
+|                                | decision is the real one FOR THIS METER - |
+|                                | but every term of `wanted = batt_w +      |
+|                                | excess` is measured, and in shadow mode   |
+|                                | the battery contributes nothing to either.|
+|                                | ⚠️ SAFETY-47: this row used to claim      |
+|                                | SAFETY-45's limit cycle was visible from a|
+|                                | shadow run. It is not - 410/720 engaged   |
+|                                | cycles live against 0/720 in shadow, on   |
+|                                | the same hour and the same code.          |
+| SAFETY-31 circulation          | OBSERVES AND MAY LATCH, legitimately. Its |
+| SAFETY-42 delivery             | evidence is MEASURED power, not a         |
+|                                | command: packs pushing against each other |
+|                                | while every one of them is told 0 W is a  |
+|                                | real fault and a latch is the right       |
+|                                | answer to it.                             |
+| operator stop (`auto` False)   | SUPPRESSED AS A CLAIM, ENFORCED AT THE    |
+|                                | WIRE. It is the one deliberate change.    |
+|                                | Its `P_SAFETY` 0 W claim out-ranks        |
+|                                | everything, so leaving it in would make   |
+|                                | the recorded decision "stopped" on every  |
+|                                | cycle - the shadow run would answer the   |
+|                                | wrong question. The actuator state is     |
+|                                | identical either way, and the wire        |
+|                                | substitution is STRICTLY STRONGER than    |
+|                                | the claim: a claim can be out-ranked, and |
+|                                | this cannot.                              |
+| inputs missing, non-finite,    | UNCHANGED. All of them resolve to 0 W,    |
+| allocator refusal, arbiter     | which is what the wire gets in shadow     |
+| contradiction                  | mode anyway, so they act redundantly and  |
+|                                | are recorded as they always were.         |
+
+⚠️ MAINTENANCE IS NOT IN THAT TABLE BECAUSE SHADOW MODE DOES NOT TOUCH IT. The
+state machines are ticked on every cycle today whether control is started or
+not, so a stopped install already runs them against a battery that does not
+move. Shadow mode inherits that, unchanged and unimproved; it is a pre-existing
+property of `auto_start: false` and it is recorded here rather than quietly
+fixed under another card's name.
+
+LEAVING SHADOW MODE
+===================
+`Controller.cycle()` re-seeds its carried command (`self.target` and each
+`inv.target`) to WIRE_W at the END of every shadow cycle, AFTER every in-cycle
+guard has read the decision. Two things follow, and both are safety properties:
+
+  * the loop's `prev_w` and its integrator track WHAT IS ACTUALLY STANDING ON
+    THE WIRE, so every shadow cycle answers "from where the plant really is,
+    what would this controller do NOW" - a true statement about the present,
+    rather than a simulation of a counterfactual plant that drifts further from
+    reality every tick;
+  * the exit is safe BY CONSTRUCTION. The carried command already equals the
+    standing command, so the first live cycle slews from 0 W like any other
+    cycle. Carrying the shadow decision instead would let the slew limiter
+    depart from a base that never existed - up to a full `slew_w` step onto a
+    battery sitting at zero.
+
+The entry is safe for the ordinary reason: the substitution happens on the very
+first write of the very first shadow cycle, and `last_write` was not 0 W, so
+that write is issued rather than skipped as unchanged.
+"""
+from __future__ import annotations
+
+from . import messages
+
+# ⚠️ CFG-03's mirror. `test_defaults_pin.py` part 2 discovers every
+# module-level name ending in OPTION_DEFAULTS and asserts each value
+# reproduces config.yaml EXACTLY, so this table cannot drift from the shipped
+# default. Nothing in the add-on may carry a literal fallback for a key a
+# mirror answers for - part 3 scans for that - which is why `main.py` asks the
+# functions below and never reads `shadow_mode` itself.
+SHADOW_OPTION_DEFAULTS = {
+    "shadow_mode": "auto",
+}
+
+#: The three values `shadow_mode` may take, in the order config.yaml's schema
+#: lists them. `validate.py` refuses anything else by name.
+MODES = ("auto", "on", "off")
+
+#: What stands on the wire while shadow mode is engaged. ⚠️ A NUMBER, NOT A
+#: SILENCE - see this module's header. It is 0.0 W for the same reason every
+#: other refusal in this add-on is 0.0 W: fail toward inaction, and keep
+#: commanding it so the inverter cannot be left latched on anything else.
+WIRE_W = 0.0
+
+#: SAFETY-47. What the recorded watts mean when a MEASURED billed quarter sized
+#: them.
+#:
+#: ⚠️ "UPPER BOUND" AND NOT "SMALLER", AND THE DIFFERENCE WAS MEASURED RATHER
+#: THAN ARGUED. Charging only ADDS offtake, so a live meter's `projected` is
+#: never below a shadow meter's and the headroom is never above it: the shadow
+#: size is >= the live size, with EQUALITY at the start of every quarter, where
+#: `900/remaining` is 1.0 and neither plant has moved. Measured pairwise over
+#: 3600 charging cycles in five configurations - 0 cycles below, 730 exactly
+#: equal. A sentence reading "smaller" would have been false on every one of
+#: those 730.
+#:
+#: ⚠️ AND IT NAMES NO FACTOR. How far under the bound a live run lands is a
+#: property of the site - 6.61x at a 1500 W cap under a 1200 W house, 1.00x at
+#: a cap that does not bind - and a number invented for the row would be a
+#: second helping of the defect this constant exists to disclose.
+SIZED_FROM_METER = (
+    "This is an upper limit, not a forecast, because the meter did not see "
+    "the battery move.")
+
+
+def mode(opts: dict) -> str:
+    """The configured `shadow_mode`, normalised to one of `MODES`.
+
+    ⚠️ AN UNRECOGNISED VALUE ANSWERS `"on"`, NOT `"auto"` AND NOT `"off"`.
+    `validate.py` refuses such a value at startup, so this branch is not meant
+    to be reachable at all; it exists because the fail-safe direction for "the
+    operator's intent cannot be read" is the one that does not move energy. A
+    typo that silently resolved to `off` would put a battery under a controller
+    whose configuration nobody could parse.
+    """
+    raw = opts.get("shadow_mode", SHADOW_OPTION_DEFAULTS["shadow_mode"])
+    text = str("" if raw is None else raw).strip().lower()
+    if text in MODES:
+        return text
+    return "on"
+
+
+def engaged(opts: dict, *, control_started: bool) -> bool:
+    """Is the battery being left alone right now?
+
+    `control_started` is `Controller.auto` - the persisted start/stop state,
+    which a fresh install gets from `auto_start` and an operator moves with the
+    *Start / stop control* button. See the header on why `auto` reads it.
+    """
+    m = mode(opts)
+    if m == "off":
+        return False
+    if m == "on":
+        return True
+    return not control_started
+
+
+def why(opts: dict, *, control_started: bool) -> str:
+    """Which rung decided, in the words an operator can act on.
+
+    ⚠️ THE REASON, NOT ONLY THE VERDICT - MUTATION.md's masking rule. `on` and
+    `auto`-while-stopped produce the same boolean and want different operator
+    actions: one is turned off by editing an option, the other by pressing a
+    button. A surface that showed only "shadow" would make a mutation that
+    swapped the two rungs invisible.
+    """
+    # ⚠️ THE LIVE SENTENCES SAY "NOT IN SHADOW MODE", NOT "THE BATTERY IS
+    # BEING CONTROLLED". The second is FALSE on a stopped install with
+    # `shadow_mode: off` - nothing is regulating there either - and a row that
+    # is false in one of the four live states is a row an operator learns to
+    # discount. What is true in every live state is that what this add-on
+    # decides reaches the inverter; whether control is RUNNING is the
+    # `Stopped` banner's question and it is answered there.
+    # UX-08: the same four rungs, in plain words. The setting is named by its
+    # value, "automatic" for `auto`, so each rung still reads differently.
+    m = mode(opts)
+    live = "what the add-on decides reaches the inverters"
+    inert = "the add-on decides but sends nothing"
+    if m == "off":
+        return f"Off, {live}"
+    if m == "on":
+        return f"On, {inert}"
+    if control_started:
+        return f"Off (automatic, control is started), {live}"
+    return f"On (automatic, control is stopped), {inert}"
+
+
+def words(opts: dict, *, control_started: bool, would_w: float | None,
+          sized_from_meter: bool, reason: str = "") -> str:
+    """The status page's `Shadow mode` row.
+
+    ⚠️ THE ROW IS RENDERED IN EVERY STATE, INCLUDING `off`. A surface whose
+    ABSENCE is how you learn which mode you are in is a surface an operator
+    has to already know about; TARIFF-11's rule is that the rendered text is
+    what gets graded, so there has to be text in both states.
+
+    `would_w` is the decision the path reached this cycle - what a live
+    controller would have put on the wire GIVEN THIS METER AND A BATTERY AT
+    0 W - and `reason` is `Resolution.explain()`, the same sentence the `Why`
+    row carries. Together they are the whole of "what would it have done, and
+    why"; without them the row would say a shadow run happened and nothing
+    about what it found.
+
+    ⚠️ `sized_from_meter` HAS NO DEFAULT, AND THAT IS SAFETY-47's WHOLE POINT.
+    It is True when a MEASURED billed-quarter headroom sized the number being
+    recorded - `arbitrage.sized_from_meter()` answers it, and it is the one
+    place the question is asked. A default of False here would be a caller
+    that forgot the caveat rendering a row that reads exactly like a caller
+    that decided it did not apply, which is the shape of defect this card is
+    about. TEST-14's rule with a new name on it.
+
+    ⚠️ AND THE PHRASE IS "THIS CYCLE", UNCONDITIONALLY, NOT ONLY WHEN THE
+    CAVEAT FIRES. Every number a shadow run records was reached from a plant
+    that did not respond; "would ask for -2 000 W" alone reads as a forecast
+    of a live run and no number here is one. UX-08 2d put it in plain words. The ⚠️ below is the STRONGER,
+    conditional statement about the cycles where the answer can be multiples
+    out - see this module's header for the measured table.
+
+    ⚠️ AND IT IS NOT KEYED ON WHETHER THE TRADE WAS CAPPED. `arbitrage`'s own
+    sentence says "SIZED BY THE CAPACITY-TARIFF GUARD" only when the headroom
+    came out BELOW the ask - which in a shadow run is the START of the
+    quarter, where the two runs still agree. By the end of the quarter
+    `900/remaining` has multiplied the headroom past the ask, the trade is
+    NOT capped, the sentence is silent and the recorded number is at its most
+    wrong. A caveat keyed on that sentence would be quietest exactly where it
+    is needed loudest. `test_arbitrage.py` part 3d-8 drives that.
+    """
+    head = why(opts, control_started=control_started)
+    if not engaged(opts, control_started=control_started):
+        return head
+    if would_w is None:
+        return (f"{head}. No decision yet, the inverters stay at "
+                f"{WIRE_W:.0f} W.")
+    # ⚠️ THE THOUSANDS SEPARATOR IS SWAPPED ON THE NUMBER ALONE. Applied to
+    # the whole sentence it ate the comma out of `head` - and `head` is the
+    # half that says WHICH RUNG decided, which is the claim MUTATION.md's
+    # masking rule says must survive.
+    num = f"{float(would_w):+,.0f}".replace(",", " ")
+    out = (f"{head}. This cycle it would ask for {num} W, the inverters stay "
+           f"at {WIRE_W:.0f} W.")
+    if sized_from_meter:
+        out += f" {SIZED_FROM_METER}"
+    if reason:
+        out += f" Why: {reason}."
+    return out
+
+
+def log_line(*, would_w: float, reason: str, sized_from_meter: bool) -> str:
+    """The action-log line for one change of shadow decision.
+
+    ⚠️ IT IS A FUNCTION FOR THE REASON `words()` IS ONE, AND SAFETY-47 LEARNED
+    IT THE EXPENSIVE WAY. This sentence used to be an f-string inside
+    `Controller._shadow_settle()`. Deleting the caveat from it there left all
+    29 files GREEN - the only check that could see the line drove a fixture
+    with `meter_source: off`, where no arbitrage decision and therefore no
+    caveat can ever be reached. A sentence assembled at a call site is a
+    sentence no check can grade, and the page would have said one thing while
+    the record a later analysis reads said another.
+
+    ⚠️ AND IT IS THE SAME `SIZED_FROM_METER` CONSTANT THE ROW CARRIES, not a
+    second wording of it. Two sentences meaning one thing is how the two
+    surfaces start disagreeing about which cycles are caveated.
+    """
+    out = (f"SHADOW: would have commanded {float(would_w):+.0f} W ON THIS "
+           f"CYCLE - {reason}")
+    if sized_from_meter:
+        out += f" {SIZED_FROM_METER}"
+    return out
+
+
+def banner(opts: dict, *, control_started: bool, latched: tuple = ()) -> tuple:
+    """`(level, text)` for the top of the status page, or `None` when live.
+
+    ⚠️ IT GOES RED FOR A STANDING LATCH. The shadow banner sits ABOVE every
+    other branch of the cascade, because "the battery is not controlled" is
+    the one sentence that may never be displaced - but a failsafe latch that
+    is up while the controller is inert is up when it stops being inert. So the
+    banner says a safety stop outlasts shadow mode, and each latch keeps its
+    own red row below, which names it and says how it clears. The words are
+    `messages.banner_shadow()`'s (UX-09); `latched` names them for callers.
+    """
+    if not engaged(opts, control_started=control_started):
+        return None
+    return ("bad" if latched else "warn", messages.banner_shadow(bool(latched)))
+
+
+def problems(opts: dict) -> list:
+    """`validate.py`'s rule: `shadow_mode` must be one of the three values.
+
+    ⚠️ THE SENTENCE SPELLS `shadow_mode`. `configui.problems_by_field()` files
+    a refusal under the field whose key its text contains; a rule that never
+    names a key lands in the page's top-level block instead, where the operator
+    cannot see which control is wrong. UX-02's whole point is that the shipped
+    validator is the only rule surface, so the rule has to be readable there.
+
+    ⚠️ AND IT IS A REFUSAL RATHER THAN A COERCION. `mode()` resolves an
+    unreadable value to shadow, which is the safe direction but is also a
+    SILENT reinterpretation of what the operator wrote - and an install left in
+    shadow mode by a typo commands nothing at all, indefinitely.
+    """
+    raw = opts.get("shadow_mode", SHADOW_OPTION_DEFAULTS["shadow_mode"])
+    text = str("" if raw is None else raw).strip().lower()
+    if text in MODES:
+        return []
+    return [f"{messages.setting('shadow_mode')} is {messages.shown(raw)}. Choose "
+            + ", ".join(f"'{m}'" for m in MODES[:-1])
+            + f" or '{MODES[-1]}'."]

goodwe_controller/app/static_tariff.py

@@ -204,6 +204,7 @@ import math
 from dataclasses import dataclass
 from datetime import datetime, timedelta, timezone
 
+from . import messages
 from .price import (
     MAX_PLAUSIBLE_EUR_KWH, Absence, PricePoint, PriceProduct, PriceRead,
     Uncertainty, _Outcome, brussels, load_prices, price_option,
@@ -262,9 +263,8 @@ def _minutes(value, field: str) -> int:
     parts = text.split(":")
     if len(parts) != 2:
         raise ProfileInvalid(
-            f"{field} is {value!r}; it must be \"HH:MM\" local Belgian time, "
-            f"e.g. \"22:00\". A bare hour or a decimal is refused rather than "
-            f"guessed at - 7.5 could be 07:30 or 07:50.")
+            f"{field} is {value!r}. Write it as \"HH:MM\" in Belgian time, "
+            f"for example \"22:00\".")
     try:
         h, m = int(parts[0]), int(parts[1])
     except ValueError:
@@ -272,9 +272,8 @@ def _minutes(value, field: str) -> int:
                              f"integers, e.g. \"07:00\"")
     if not (0 <= m < 60) or not (0 <= h <= 24) or (h == 24 and m != 0):
         raise ProfileInvalid(
-            f"{field} is {value!r}, which is not a time of day. Hours run 0-23, "
-            f"minutes 0-59; \"24:00\" is accepted only as an END meaning "
-            f"midnight at the end of the day.")
+            f"{field} is {value!r}, which is not a time of day. Use 00:00 to "
+            f"23:59, or \"24:00\" as an end time.")
     return h * 60 + m
 
 
@@ -286,11 +285,8 @@ def _days(value, field: str) -> frozenset:
     """
     if value is None:
         raise ProfileInvalid(
-            f"{field} is missing. Name the days this period applies to - "
-            f"\"mon-fri\", \"sat,sun\" or \"all\". It is required rather than "
-            f"defaulted to every day, because a Belgian night tariff that "
-            f"silently covered the weekend too would misprice 48 h a week with "
-            f"nothing reporting it.")
+            f"{field} is missing. Name the days, for example \"mon-fri\", "
+            f"\"sat,sun\" or \"all\".")
     tokens = []
     if isinstance(value, (list, tuple)):
         for item in value:
@@ -367,10 +363,8 @@ def _price(value, field: str, means: str = None) -> float:
         raise ProfileInvalid(f"{field} is {value!r}, which is not finite")
     if abs(out) > MAX_PLAUSIBLE_EUR_KWH:
         raise ProfileInvalid(
-            f"{field} is {out} EUR/kWh, beyond +-{MAX_PLAUSIBLE_EUR_KWH}. The "
-            f"usual cause is a figure in cents or in EUR/MWh - 34 instead of "
-            f"0.34 - which would make every hour look like an emergency. Same "
-            f"bound the fetched feeds are held to (price.py `_validate_raw`).")
+            f"{field} is {out} EUR/kWh, beyond +-{MAX_PLAUSIBLE_EUR_KWH}. "
+            f"Write the price in EUR/kWh, for example 0.34 and not 34.")
     return out
 
 
@@ -422,9 +416,8 @@ class StaticProfile:
         self.option = option
         if not self.periods:
             raise ProfileInvalid(
-                f"{option} has no periods. A profile with no periods is "
-                f"not a fixed tariff, it is an absent one - leave the option "
-                f"empty to say that on purpose (§11.4 then applies).")
+                f"{option} has no periods. Add at least one, or leave the "
+                f"setting empty.")
         _check_tiling(self.periods, option=option)
 
     # -- what kind of tariff this is, DERIVED --------------------------------
@@ -558,10 +551,7 @@ def _raise_gap(weekday, start, end, option="static_profile"):
     raise ProfileInvalid(
         f"{option} leaves {DAY_NAMES[weekday]} "
         f"{_hhmm(start)}-{_hhmm(end)} with no period, so those hours have no "
-        f"price. Refused rather than defaulted: an invented price is one an "
-        f"optimiser would trade on, and §11.4 already says what a missing price "
-        f"means. Add a period covering it - remember a window written "
-        f"\"22:00-07:00 mon-fri\" does NOT cover Saturday morning.")
+        f"price. Add a period that covers them.")
 
 
 def _raise_overlap(weekday, over, end, periods, option="static_profile"):
@@ -569,9 +559,8 @@ def _raise_overlap(weekday, over, end, periods, option="static_profile"):
     names = [p.name for p in periods if p.covers(weekday, start)]
     raise ProfileInvalid(
         f"{option} gives {DAY_NAMES[weekday]} {_hhmm(start)}-"
-        f"{_hhmm(end)} {n} prices at once ({', '.join(names)}). Two prices for "
-        f"one hour means one of them silently wins on list order. Narrow one of "
-        f"the windows or split the day selector.")
+        f"{_hhmm(end)} {n} prices at once ({', '.join(names)}). Make the "
+        f"periods stop overlapping.")
 
 
 def parse_static_profile(value, *, option: str = "static_profile",
@@ -609,28 +598,21 @@ def parse_static_profile(value, *, option: str = "static_profile",
             value = json.loads(text)
         except ValueError as e:
             raise ProfileInvalid(
-                f"{option} is not valid JSON ({e}). It is a JSON object "
-                f"with a \"periods\" list, on one line, e.g.\n"
-                f'  {{"periods": [{{"name":"day","from":"07:00","to":"22:00",'
-                f'"days":"mon-fri","eur_per_kwh":0.34}}, ...]}}\n'
-                f"Leave it empty for a dynamic-only or price-free site.")
+                f"{messages.not_valid(option, e)}. Copy the example from the "
+                f"documentation, or leave it empty if you have no fixed "
+                f"tariff.")
 
     if isinstance(value, dict):
         tz = str(value.get("timezone", "") or "").strip().lower()
         if tz not in SUPPORTED_TZ:
             raise ProfileInvalid(
                 f"{option}.timezone is {value.get('timezone')!r}. Only "
-                f"Europe/Brussels is supported: the shipped image carries no tz "
-                f"database (see app/price.py), so any other zone could not be "
-                f"honoured and would be silently treated as Brussels - which is "
-                f"wrong by an hour for part of the year.")
+                f"Europe/Brussels is supported.")
         rows = value.get("periods")
         if rows is None:
             raise ProfileInvalid(
-                f"{option} has no \"periods\" list. Even a fully-fixed "
-                f"tariff is written as one period covering 00:00-24:00 all days "
-                f"- one shape for both products, so nothing downstream branches "
-                f"on which kind of site this is.")
+                f"{option} has no \"periods\" list. A fixed price is one "
+                f"period from 00:00 to 24:00 on all days.")
     else:
         rows = value
 
@@ -1137,18 +1119,24 @@ class TariffPlan:
         for 76 % of a 40-hour soak and mixed 900/3600 s for 70 %, and no HTTP
         surface said either.
         """
+        # UX-08: plain words, every figure in its own slot as before.
         if not self.has_prices:
-            return f"no tariff - {self.read.reason}"
-        tag = {"provider": self.read.provider, "static": "static_profile",
-               "fallback": "static_profile (feed down)"}.get(self.origin,
-                                                             self.origin)
+            return f"no prices, {self.read.reason}"
+        tag = {"provider": "the price feed", "static": "your fixed tariff",
+               "fallback": "your fixed tariff, because the feed is down"}.get(
+                   self.origin, self.origin)
+        what = {PriceProduct.DAY_AHEAD: "day-ahead prices",
+                PriceProduct.REALTIME: "real-time prices",
+                PriceProduct.STATIC: "day/night prices",
+                PriceProduct.FIXED: "a fixed price"}.get(self.product,
+                                                         str(self.product))
         gaps = self.spacings_s
-        return (f"{self.product.value} from {tag}, "
-                f"{self.n_points} points over {self.hours} h, "
-                f"{self.n_firm} firm / {self.n_carried} carried"
-                + (f", {'+'.join(str(g) for g in gaps)} s spacing"
+        return (f"{what} from {tag}, "
+                f"{self.n_points} prices over {self.hours} hours, "
+                f"{self.n_firm} published and {self.n_carried} estimated"
+                + (f", {'+'.join(str(g) for g in gaps)} s apart"
                    if gaps else "")
-                + (", provisional" if self.provisional else ""))
+                + (", not final yet" if self.provisional else ""))
 
 
 def _whole_hours(points) -> int:
@@ -1242,21 +1230,22 @@ def static_status(opts: dict, now: datetime):
         plan = static_plan(opts, now, now + timedelta(days=MEAN_WINDOW_DAYS),
                            now=now)
     except ProfileInvalid as e:
-        _LOG.warning("static_profile is unusable (%s); no cheap window. This "
-                     "should have been refused at startup - see validate.py", e)
-        return False, f"static_profile unusable: {e}"
+        _LOG.warning("static_profile cannot be used (%s), so there is no "
+                     "cheap window. The start-up check should have refused "
+                     "it.", e)
+        return False, f"Fixed tariff cannot be used: {e}"
     if not plan.has_prices:
-        return False, "no static profile"
+        return False, "No fixed tariff set"
     cheap = plan.cheap_now(now)
     window = plan.window_at(now)
     price = plan.price_at(now)
     when = plan.profile.next_change(now)
     until = "" if when is None else f" until {brussels(when):%H:%M}"
-    kind = ("fixed" if plan.product is PriceProduct.FIXED else "day/night")
-    return cheap, (f"{kind}: {window}{until} at {price:.4f} EUR/kWh, "
-                   f"mean {plan.mean_eur_kwh():.4f} over "
-                   f"{MEAN_WINDOW_DAYS} d - "
-                   f"{'CHEAP window' if cheap else 'not a cheap window'}")
+    kind = ("Fixed" if plan.product is PriceProduct.FIXED else "Day/night")
+    return cheap, (f"{kind} tariff, {window}{until}: {price:.4f} EUR/kWh, "
+                   f"{'cheap' if cheap else 'not cheap'} against the "
+                   f"{MEAN_WINDOW_DAYS}-day average of "
+                   f"{plan.mean_eur_kwh():.4f}")
 
 
 async def resolve_tariff(opts: dict, since: datetime, until: datetime,
@@ -1353,13 +1342,12 @@ def _degrade(opts, read, since, until, stamp) -> TariffPlan:
                      "(%s), so there is no tariff at all", e)
         profile = None
     if profile is None:
-        _LOG.warning("§11.4: %s, and no static_profile is configured to fall "
-                     "back to. The plan is provisional and arbitrage is off; "
-                     "self-consumption, peak shaving and reserve management "
-                     "continue (§6, §10.1).", read.reason)
+        _LOG.warning("%s, and no static_profile is set to fall back to, so "
+                     "prices are provisional and trading is off. Peak "
+                     "limiting and home use go on.", read.reason)
         return TariffPlan(read, None, "none")
-    _LOG.warning("§11.4: %s - falling back to the static profile, plan marked "
-                 "PROVISIONAL, arbitrage off.", read.reason)
+    _LOG.warning("%s, so the static_profile tariff is used instead, marked "
+                 "provisional, and trading is off.", read.reason)
     points = profile.series(since, until, provisional=True)
     return TariffPlan(
         PriceRead.series(points, profile.product, "static_profile", stamp),

goodwe_controller/app/store.py

@@ -328,8 +328,8 @@ def migrate_unit_keys(store, unit: str, roster=None) -> MigrationReport:
         # ⚠️ NOT MARKED DONE. A migration that lost state must run again on the
         # next start rather than be recorded as finished - the one thing worse
         # than a failed migration is a failed migration a later version skips.
-        _LOG.error("per-inverter store migration LOST STATE and has not been "
-                   "marked done: %s", rep.explain())
+        _LOG.error("Moving the saved state to one part per inverter lost "
+                   "data, so it is not marked done: %s", rep.explain())
     return rep
 
 

goodwe_controller/app/validate.py

@@ -322,15 +322,20 @@ WHAT IS DELIBERATELY *NOT* REFUSED, because it is untidy rather than unsafe:
 
 import logging
 
+from . import messages
 from .arbitrage import enabled as arbitrage_on
 from .control import SLEW_RAIL_FRAC, LOOP_TICK_S, PLANT_SETTLE_S
 from .custom_formula import (
-    FormulaInvalid, implausible_all_in, parse_price_formula, stale_card)
+    EXPORT_FORMULA_OPTION, FormulaInvalid, implausible_all_in,
+    parse_export_formula, parse_price_formula, stale_card)
 from .inverter import roster_entries
 from .maintenance import MAINT_OPTION_DEFAULTS
 from .p1 import is_enabled, validate_meter_options
 from .peakguard import PEAK_OPTION_DEFAULTS
-from .price import PRICE_OPTION_DEFAULTS, PROVIDERS, RETIRED_PROVIDERS
+from .price import (
+    PRICE_OPTION_DEFAULTS, PROVIDERS, RETIRED_PROVIDERS,
+    SUPERSEDED_TAXES_DEFAULTS_EUR_KWH)
+from .shadow import problems as shadow_problems
 from .static_tariff import (
     ProfileInvalid, TAXES_PROFILE_OPTION, parse_static_profile,
     parse_taxes_profile)
@@ -567,6 +572,17 @@ def _unit_label(opts: dict, index: int) -> str:
     return f" ({name or f'inverters[{index}]'})"
 
 
+def S(key: str, where: str = "") -> str:
+    """A setting as a refusal names it; `where` is `_unit_label()`'s " (name)"."""
+    return messages.setting(key, where.strip().strip("()"))
+
+
+def _labels(keys, joiner: str = "and") -> str:
+    """Several settings, each with its key: the config panel files a refusal
+    under every key it names (`configui.problems_by_field()`)."""
+    return f" {joiner} ".join(S(k) for k in keys)
+
+
 def _roster_problems(opts: dict) -> list[str]:
     """Rule 9 (CFG-04): the `inverters:` roster, refused where it cannot mean
     what it says.
@@ -621,11 +637,9 @@ def _roster_problems(opts: dict) -> list[str]:
     if raw is None or raw == "" or raw == []:
         return problems
     if not isinstance(raw, (list, tuple)):
-        return [f"inverters is {type(raw).__name__} {raw!r}, and it must be a "
-                "LIST of inverter objects - one per inverter, each naming its "
-                "own name, setpoint_entity and max_w. A single inverter needs "
-                "no list at all: leave `inverters` empty and the flat "
-                "setpoint_entity/soc_entity/batt_entity/max_w keys describe it."]
+        return [f"{S('inverters')} is {type(raw).__name__} {raw!r}, not a list. "
+                "Add one entry per inverter, or leave it empty for a single "
+                "inverter."]
 
     entries = roster_entries(opts)
     seen: dict = {}
@@ -633,45 +647,31 @@ def _roster_problems(opts: dict) -> list[str]:
         where = f"inverters[{i}]"
         if not isinstance(entry, dict):
             problems.append(
-                f"{where} is {type(entry).__name__} {entry!r}, and every entry "
-                "must be an object with at least name, setpoint_entity and "
-                "max_w.")
+                f"{where} in the “Inverter list” is {messages.shown(entry)}. Each entry needs "
+                "a name, a setpoint entity and an inverter rating.")
             continue
         name = str(entry.get("name") or "").strip()
         if not name:
             problems.append(
-                f"{where} has no name. Every inverter needs one: the Store "
-                "namespaces this unit's SAFETY-02 latch, its heartbeat and its "
-                "write bookkeeping under it, so two unnamed units would share "
-                "one namespace and a trip caused by one would latch the other. "
-                "Any short identifier works - inverter-a, inverter-b, garage.")
+                f"{where} in the “Inverter list” has no name. Give every "
+                "inverter a short name, for example inverter-a.")
         elif name in seen:
             problems.append(
-                f"{where} and {seen[name]} are both called {name!r}. The Store "
-                "keys every per-unit latch under the unit's name, so two units "
-                "with one name share one SAFETY-02 latch and one heartbeat "
-                "deadline - a trip caused by either would stop both, and an "
-                "operator clearing it would clear both. Give them different "
-                "names.")
+                f"{where} and {seen[name]} are both called {name!r}. Give every "
+                "inverter its own name.")
         else:
             seen[name] = where
         who = f"{where} ({name})" if name else where
         if not str(entry.get("setpoint_entity") or "").strip():
             problems.append(
-                f"{who} has no setpoint_entity, so this add-on cannot command "
-                "it. It would sit in the roster, take a share of the site "
-                "target every cycle and deliver none of it, while the status "
-                "page showed a site running at full strength. Give it the "
-                "ESPHome number entity that carries ITS setpoint, or remove "
-                "the entry.")
+                f"{who} has no {S('setpoint_entity')}, so the add-on cannot "
+                "control it. Set its ESPHome number entity, or remove the "
+                "entry.")
         if _number(entry, "max_w", None) is None or (_number(entry, "max_w", None) or 0) <= 0:
             problems.append(
-                f"{who} has no usable max_w (got {entry.get('max_w')!r}). It is "
-                "the supervised cap on what may be written to THIS inverter, it "
-                "is not shared with any other unit and it is deliberately not "
-                "inherited from the flat max_w - a rating borrowed from a "
-                "sibling is exactly what DEV-02 removed. State this unit's own "
-                "rating in watts.")
+                f"{who} has no usable {S('max_w')}: it is "
+                f"{messages.shown(entry.get('max_w'))}. Set this inverter's own rating in "
+                "watts.")
 
     # --- (f) and (g): OPT-09's capacity, which is optional but not partial ---
     stated, blank = [], []
@@ -690,35 +690,21 @@ def _roster_problems(opts: dict) -> list[str]:
             val = None
         if val is None or not (val > 0.0):
             problems.append(
-                f"{who} has capacity_kwh {raw!r}, which is not a usable number "
-                "of kilowatt-hours. It is THIS pack's usable capacity and it is "
-                "read to weight the split of the site target by ENERGY headroom "
-                "rather than by power rating; a zero or an unparseable value is "
-                "a pack the split would quietly stop preferring while the box "
-                "still shows a value. State it in kWh, or leave it empty on "
-                "every entry.")
+                f"{who} has {S('capacity_kwh')} {messages.shown(raw)}, which is not a usable "
+                "number. Set it in kWh, or leave it empty on every inverter.")
         else:
             stated.append(who)
     if stated and blank:
         problems.append(
-            f"capacity_kwh is stated on {', '.join(stated)} and left empty on "
-            f"{', '.join(blank)}. It is OPTIONAL but it is not PARTIAL: the "
-            "split weights one pack's energy headroom against another's, so a "
-            "pack measured in kWh beside a sibling that weighs a dimensionless "
-            "1.0 is not a comparison - the add-on answers 'no opinion' for the "
-            "whole roster and the value you filled in changes nothing. State a "
-            "capacity for every inverter, or for none of them.")
+            f"{S('capacity_kwh')} is set on {', '.join(stated)} but empty on "
+            f"{', '.join(blank)}. Set it on every inverter, or on none.")
 
     flat_sp = str(opts.get("setpoint_entity") or "").strip()
     if entries and flat_sp:
         problems.append(
-            f"setpoint_entity is set to {flat_sp} AND an inverters list of "
-            f"{len(entries)} is declared. The flat setpoint_entity/soc_entity/"
-            "batt_entity/max_w keys are the SINGLE-inverter shape and are not "
-            "read at all once a roster exists, so this config declares an "
-            "actuator that nothing will ever write - a site running quietly "
-            "smaller than its own configuration. Move that inverter into the "
-            "list as its own entry and clear setpoint_entity.")
+            f"{S('setpoint_entity')} is set to {flat_sp}, but the "
+            f"{S('inverters')} is also filled in. Move that inverter into the "
+            "list and clear this setting.")
     return problems
 
 
@@ -756,17 +742,14 @@ def validate_unit_ranges(units, *, skip_entity: str = "") -> list[str]:
         name = getattr(unit, "name", entity)
         if dev_max is not None and cap > float(dev_max):
             problems.append(
-                f"{name}: max_w is {cap:.0f} W but {entity} accepts at most "
-                f"{float(dev_max):.0f} W - THE DEVICE WINS, so the {cap:.0f} W "
-                f"configured for this inverter would silently never happen. "
-                f"Lower this entry's max_w to {float(dev_max):.0f} W or less.")
+                f"{name}: {S('max_w')} is {cap:.0f} W, but {entity} accepts at "
+                f"most {float(dev_max):.0f} W. Lower this inverter's rating to "
+                f"{float(dev_max):.0f} W or less.")
         elif dev_min is not None and -cap < float(dev_min):
             problems.append(
-                f"{name}: max_w is {cap:.0f} W, so this controller may command "
-                f"{-cap:.0f} W, but {entity} accepts no less than "
-                f"{float(dev_min):.0f} W - THE DEVICE WINS on the charge side. "
-                f"Lower this entry's max_w to {abs(float(dev_min)):.0f} W or "
-                "less.")
+                f"{name}: {S('max_w')} is {cap:.0f} W, but {entity} accepts no "
+                f"less than {float(dev_min):.0f} W when charging. Lower this "
+                f"inverter's rating to {abs(float(dev_min)):.0f} W or less.")
     return problems
 
 
@@ -799,11 +782,8 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     writers = actuator_writers(opts)
     if not writers:
         problems.append(
-            "setpoint_entity is not set, so this add-on has no actuator: every "
-            "write is a no-op, the device's own rating is never read, and the "
-            "ESP32 heartbeat that holds off the layer-1 failsafe never happens. "
-            "It would run, look healthy, and move no energy at all. Set it to "
-            "the ESPHome number entity that carries the setpoint.")
+            f"{S('setpoint_entity')} is empty, so the add-on cannot control the "
+            "inverter. Set it to the ESPHome number entity for the setpoint.")
     # SAFETY-28. The §1.5 non-goal, graded on the writers rather than on the
     # count of option keys. Read `actuator_writers()` for why the old check went
     # green on the very config this one is here to refuse.
@@ -818,15 +798,9 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     for actuator, who in sorted(writers.items()):
         if len(who) > 1:
             problems.append(
-                f"{len(who)} configured writers can reach the one actuator "
-                f"{actuator}: {', '.join(who)}. specs §1.5 makes any "
-                "configuration in which two writers can reach one actuator a "
-                "non-goal - two independent setpoints on one inverter is the "
-                "arbitration problem this add-on refuses to have, and at "
-                "runtime it is a meter-emulation target being written twice a "
-                "second by two strategies that cannot see each other. Give "
-                "each actuator exactly one writer, or point the second one at "
-                "its own entity.")
+                f"{len(who)} settings point at the same inverter entity "
+                f"{actuator}: {', '.join(who)}. Give each inverter its own "
+                "setpoint entity.")
 
     # --- 9. CFG-04's roster, graded BEFORE anything reads a per-unit number --
     # ⚠️ FIRST, THOUGH IT IS THE NEWEST RULE. Rules 5 and 6 below now ask the
@@ -837,6 +811,18 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     # missing rating one line up.
     problems.extend(_roster_problems(opts))
 
+    # --- 11. SAFETY-10's shadow mode, and it is a REFUSAL ---------------------
+    # `shadow_mode` decides whether this controller commands the battery at all,
+    # so an unreadable value is not a detail to log and carry on past.
+    # `shadow.mode()` resolves an unrecognised one to SHADOW - the direction
+    # that does not move energy - and an install silently reinterpreted that way
+    # commands nothing, indefinitely, while its status page calmly explains
+    # that this is intentional. UX-02 made this validator the ONE rule surface
+    # both editors read, so the refusal belongs here rather than in a coercion
+    # nobody can see. The sentence spells `shadow_mode` so
+    # `configui.problems_by_field()` can file it under the field.
+    problems.extend(shadow_problems(opts))
+
     # --- 2. the configured ceiling against the device's own rating -----------
     # ⚠️ THE FLAT `max_w`, AND ONLY THE FLAT ONE. `dev_min`/`dev_max` are ONE
     # device's range - the flat `setpoint_entity`'s - so this rule can only ever
@@ -845,7 +831,8 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     # has answered; it is not called from here because at startup no device has.
     max_w = _number(opts, "max_w", 2000.0)
     if max_w is None:
-        problems.append(f"max_w {opts.get('max_w')!r} is not a number")
+        problems.append(f"{S('max_w')} is {messages.shown(opts.get('max_w'))}, which is not "
+                        "a number. Set it in watts.")
     # ⚠️ config.yaml's int(100,5000) already blocks this on a real install, so
     # the check is not for the Supervisor path - it is because
     # validate_startup_config() is now also sim/inject.py's entry point and can
@@ -856,24 +843,19 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     # nonsense config it is.
     elif max_w <= 0:
         problems.append(
-            f"max_w is {max_w:.0f} W and must be positive - it is a magnitude, "
-            "not a signed setpoint. At or below zero the arbiter's supervised "
-            f"limit becomes lo={-max_w:.0f} / hi={max_w:.0f}, which is a "
-            "contradiction it resolves to 0 W, so the controller would look "
-            "like it was tripping rather than misconfigured.")
+            f"{S('max_w')} is {max_w:.0f} W. Set it above 0 W.")
     elif dev_max is not None and max_w > dev_max:
         problems.append(
-            f"max_w is {max_w:.0f} W but {opts.get('setpoint_entity') or 'the setpoint device'} accepts at "
-            f"most {dev_max:.0f} W - THE DEVICE WINS, so the {max_w:.0f} W you "
-            f"configured would silently never happen. Lower max_w to "
-            f"{dev_max:.0f} W or less, or point setpoint_entity at a device that "
-            f"can take {max_w:.0f} W.")
+            f"{S('max_w')} is {max_w:.0f} W, but "
+            f"{opts.get('setpoint_entity') or 'the setpoint entity'} accepts at "
+            f"most {dev_max:.0f} W. Lower the rating to {dev_max:.0f} W or "
+            "less.")
     elif dev_min is not None and -max_w < dev_min:
         problems.append(
-            f"max_w is {max_w:.0f} W, so this controller may command "
-            f"{-max_w:.0f} W, but {opts.get('setpoint_entity') or 'the setpoint device'} accepts no less "
-            f"than {dev_min:.0f} W - THE DEVICE WINS on the charge side. Lower "
-            f"max_w to {abs(dev_min):.0f} W or less.")
+            f"{S('max_w')} is {max_w:.0f} W, but "
+            f"{opts.get('setpoint_entity') or 'the setpoint entity'} accepts no "
+            f"less than {dev_min:.0f} W when charging. Lower the rating to "
+            f"{abs(dev_min):.0f} W or less.")
 
     # --- 3. a meter that can actually read -----------------------------------
     # ⚠️ Not a second copy of these rules - p1.py owns them, because
@@ -882,9 +864,10 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     phases = _number(opts, "meter_phases", 1.0)
     max_age_s = _number(opts, "meter_max_age_s", 30.0)
     if phases is None or max_age_s is None:
-        problems.append("meter_phases and meter_max_age_s must both be numbers "
-                        f"(got {opts.get('meter_phases')!r} / "
-                        f"{opts.get('meter_max_age_s')!r})")
+        problems.append(f"{S('meter_phases')} and {S('meter_max_age_s')} must "
+                        f"both be numbers. They are "
+                        f"{messages.shown(opts.get('meter_phases'))} and "
+                        f"{messages.shown(opts.get('meter_max_age_s'))}.")
     else:
         problems.extend(validate_meter_options(opts, int(phases), max_age_s))
 
@@ -905,15 +888,9 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     if (is_enabled(opts) and max_age_s is not None
             and max_age_s > FIRMWARE_INGEST_VETO_S):
         problems.append(
-            f"meter_max_age_s is {max_age_s:.0f} s but the ESP32 firmware vetoes "
-            f"any P1 sample at {FIRMWARE_INGEST_VETO_S:.0f} s and forces the "
-            "layer-1 failsafe - THE FIRMWARE WINS, and it wins silently. This "
-            f"add-on would treat a {max_age_s - 1:.0f} s reading as fresh and "
-            "keep commanding, while the inverter sat at 0 W with a healthy-"
-            "looking meter on the status page. Lower meter_max_age_s to "
-            f"{FIRMWARE_INGEST_VETO_S:.0f} s or less (30 s is the tested value), "
-            "or rebuild the firmware with a matching max_age_s and update "
-            "validate.FIRMWARE_INGEST_VETO_S.")
+            f"{S('meter_max_age_s')} is {max_age_s:.0f} s, but the control "
+            f"board stops the inverter after {FIRMWARE_INGEST_VETO_S:.0f} s. "
+            f"Set it to {FIRMWARE_INGEST_VETO_S:.0f} s or less.")
 
     # --- 5. a sign watchdog that can actually fire ---------------------------
     # ⚠️ Strictly `>=`, matching the predicate exactly: watchdog.py tests
@@ -940,19 +917,15 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     caps = [cap for _, cap in caps_ix]
     weakest = min(caps) if caps else None
     if sign_w is None:
-        problems.append(f"sign_disagree_w {opts.get('sign_disagree_w')!r} is not a number")
+        problems.append(f"{S('sign_disagree_w')} is "
+                        f"{messages.shown(opts.get('sign_disagree_w'))}, which is not a "
+                        "number. Set it back to 300 W.")
     elif weakest is not None and weakest > 0 and sign_w >= weakest:
         where = _unit_label(opts, min(caps_ix, key=lambda p: p[1])[0])
         problems.append(
-            f"sign_disagree_w is {sign_w:.0f} W but max_w{where} is "
-            f"{weakest:.0f} W, so "
-            "the SAFETY-02 sign-disagreement watchdog can never fire: the "
-            "arbiter never lets a command exceed max_w, and the watchdog needs "
-            f"a command over {sign_w:.0f} W. It would sit there reporting "
-            "'armed' on the status page while being incapable of tripping - the "
-            f"one runaway failure mode this system has actually observed. Lower "
-            f"sign_disagree_w below {weakest:.0f} W (300 W is the measured "
-            "default), or raise max_w.")
+            f"{S('sign_disagree_w')} is {sign_w:.0f} W, not below "
+            f"{S('max_w', where)} at {weakest:.0f} W, so this safety stop can "
+            f"never trip. Lower it or raise the rating.")
 
     # ⚠️ AND THE SAME RULE FOR SAFETY-30's PER-UNIT THRESHOLD, WHICH IS A
     # SEPARATE COMPARISON AND THEREFORE A SEPARATE WAY TO DISARM. It grades a
@@ -998,20 +971,15 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     unit_where = (_unit_label(opts, min(caps_ix, key=lambda p: p[1])[0])
                   if caps_ix else "")
     if unit_sign_w is None:
-        problems.append(f"unit_sign_disagree_w "
-                        f"{opts.get('unit_sign_disagree_w')!r} is not a number")
+        problems.append(f"{S('unit_sign_disagree_w')} is "
+                        f"{messages.shown(opts.get('unit_sign_disagree_w'))}, which is not a "
+                        "number. Set it back to "
+                        f"{SIGN_OPTION_DEFAULTS['unit_sign_disagree_w']:.0f} W.")
     elif weakest is not None and weakest > 0 and unit_sign_w >= weakest:
         problems.append(
-            f"unit_sign_disagree_w is {unit_sign_w:.0f} W but max_w{unit_where}"
-            f" is {weakest:.0f} W, so the SAFETY-30 per-inverter sign-disagreement "
-            "watchdog can never fire: no inverter is ever commanded past max_w, "
-            f"and the watchdog needs a command over {unit_sign_w:.0f} W. At two "
-            "inverters that is the guard which catches a unit doing the "
-            "OPPOSITE of what it was told while its sibling covers for it at "
-            "the meter - the case the site-level watchdog is structurally "
-            f"blind to. Lower unit_sign_disagree_w below {weakest:.0f} W "
-            f"({SIGN_OPTION_DEFAULTS['unit_sign_disagree_w']:.0f} W is the "
-            "measured default), or raise max_w.")
+            f"{S('unit_sign_disagree_w')} is {unit_sign_w:.0f} W, not below "
+            f"{S('max_w', unit_where)} at {weakest:.0f} W, so this safety stop "
+            f"can never trip. Lower it or raise the rating.")
 
     # --- 6. a maintenance charge the ceiling can actually accommodate --------
     # ⚠️ Strictly `>`, matching the arbiter exactly. The shaping is
@@ -1084,18 +1052,14 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     maint_where = _unit_label(opts, maint_index)
     if charge_w is None:
         problems.append(
-            f"maintenance_charge_w {opts.get('maintenance_charge_w')!r} is not a number")
+            f"{S('maintenance_charge_w')} is "
+            f"{messages.shown(opts.get('maintenance_charge_w'))}, which is not a number. Set "
+            "it in watts.")
     elif maint_cap is not None and maint_cap > 0 and charge_w > maint_cap:
         problems.append(
-            f"maintenance_charge_w is {charge_w:.0f} W but max_w{maint_where} is "
-            f"{maint_cap:.0f} W, so a maintenance charge in a cheap window can "
-            "never happen: the shaping asks the arbiter for at most "
-            f"{-charge_w:.0f} W while the supervised limit allows no less than "
-            f"{-maint_cap:.0f} W, which is a contradiction it resolves to 0 W - "
-            "THE CEILING WINS, and what you would see is an ARBITER "
-            "CONTRADICTION line that reads like a bug rather than like these "
-            f"two numbers. Lower maintenance_charge_w to {maint_cap:.0f} W or "
-            f"less, or raise max_w to at least {charge_w:.0f} W.")
+            f"{S('maintenance_charge_w')} is {charge_w:.0f} W, but the "
+            f"{S('max_w', maint_where)} is {maint_cap:.0f} W, so the monthly "
+            f"recharge cannot run. Lower it to {maint_cap:.0f} W or less.")
 
     # --- 10. a slew rate the plant can actually follow -----------------------
     # ⚠️ SAFETY-39. The one rule here that grades a RATIO rather than a
@@ -1124,34 +1088,19 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     slew_w = _number(opts, "slew_w", 0.0)
     rail = site_rail_w(opts)
     if slew_w is None:
-        problems.append(f"slew_w {opts.get('slew_w')!r} is not a number")
+        problems.append(f"{S('slew_w')} is {messages.shown(opts.get('slew_w'))}, which is "
+                        "not a number. Set it to 0 to follow the inverter "
+                        "rating.")
     elif slew_w < 0:
         problems.append(
-            f"slew_w is {slew_w:.0f} W and must not be negative - it is a "
-            "magnitude, and 0 means 'follow max_w' (the recommended setting).")
+            f"{S('slew_w')} is {slew_w:.0f} W and cannot be negative. Set it to "
+            "0 to follow the inverter rating.")
     elif slew_w and rail is not None and rail > 0:
         bound = SLEW_RAIL_FRAC * rail
         if slew_w > bound + 1.0:
-            ticks = rail / slew_w
             problems.append(
-                f"slew_w is {slew_w:.0f} W against a site rail of {rail:.0f} W, "
-                f"so the loop crosses its whole output range in {ticks:.1f} "
-                f"cycles - {ticks * LOOP_TICK_S:.0f} s at the {LOOP_TICK_S:.0f} s "
-                f"tick this site was measured running - while the plant takes "
-                f"{PLANT_SETTLE_S:.0f} s to settle (goodwe/NOTES.md §5.10, a "
-                "1.78 kW step). The controller would command its entire range "
-                "before it could observe its answer to the first step, which is "
-                "not a slow loop, it is a loop that MANUFACTURES the error it "
-                "then chases: measured on this system 2026-09-05, a 3.4 kW "
-                "export drove the setpoint 380 -> 5000 W in five ticks, the "
-                "battery to -5154 W past a 5000 VA rating, and the grid from "
-                "3.4 kW of export to 2.8 kW of import. The stated limit - the "
-                "command moves at most slew_w per cycle, so it cannot jump "
-                "ahead of the inverter - is untrue at this rail; THE PLANT "
-                f"WINS, and it has no status row. Set slew_w to 0, which means "
-                f"'follow the rail' and resolves to {bound:.0f} W here and "
-                "moves on its own if the rail does, or write a value at or "
-                f"below {bound:.0f} W. Lower is always accepted.")
+                f"{S('slew_w')} is {slew_w:.0f} W, too fast for a {rail:.0f} W "
+                f"site. Set it to 0 or to at most {bound:.0f} W.")
 
     # --- 7. two price sources on one site ------------------------------------
     problems.extend(_price_problems(opts))
@@ -1182,32 +1131,23 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
         where = _unit_label(opts, _ix)
         if soc_floor is None or bms_floor is None:
             problems.append(
-                f"peak_soc_floor and bms_soc_floor{where} must both be numbers "
-                f"(got {opts.get('peak_soc_floor')!r} / {_raw!r})")
+                f"{S('peak_soc_floor')} and {S('bms_soc_floor', where)} must "
+                f"both be numbers. They are {messages.shown(opts.get('peak_soc_floor'))} and "
+                f"{messages.shown(_raw)}.")
         elif soc_floor <= bms_floor:
             problems.append(
-                f"peak_soc_floor is {soc_floor:.0f} % but the pack's own cut-out "
-                f"(bms_soc_floor{where}) is {bms_floor:.0f} %, so SAFETY-07's forced "
-                "discharge has no EMS-side bound at all - THE BMS WINS, and it is "
-                "the pack's protection rather than yours. The guard would report a "
-                "SoC floor on its status page while being incapable of ever being "
-                "the thing that stops the discharge, and the symptom of that is a "
-                "battery repeatedly sitting at the BMS limit with no record of why "
-                f"- which looks exactly like the SoC drift the maintenance cycle "
-                f"exists to correct. Raise peak_soc_floor above {bms_floor:.0f} % "
-                f"(the shipped default is "
-                f"{PEAK_OPTION_DEFAULTS['peak_soc_floor']:.0f} %), or correct "
-                f"bms_soc_floor{where} if it does not match this pack.")
+                f"{S('peak_soc_floor')} is {soc_floor:.0f} %, not above the "
+                f"{S('bms_soc_floor', where)} of {bms_floor:.0f} %. Raise the "
+                f"reserve above {bms_floor:.0f} %, or correct the cut-out "
+                "level.")
 
     # --- warnings: real, but not worth refusing over -------------------------
     integ = opts.get("integrator_max_w")
     integ_w = None if not integ else _number(opts, "integrator_max_w", None)
     if integ_w is not None and max_w is not None and integ_w > max_w:
         _LOG.warning(
-            "integrator_max_w %.0f W is above max_w %.0f W. Not refused - the "
-            "arbiter still bounds the wire to +-max_w - but the only thing the "
-            "extra headroom buys is more wrong-direction power to unwind after "
-            "saturation. 0 (follow max_w) is the recommended value.",
+            "integrator_max_w %.0f W is above max_w %.0f W. This is allowed, "
+            "but it only adds overshoot, so 0 is recommended.",
             integ_w, max_w)
 
     # ⚠️ THE SIBLING OF RULE 6, AND NOT THE SAME CASE - see the docstring. The
@@ -1230,15 +1170,13 @@ def validate_startup_config(opts: dict, dev_min=None, dev_max=None) -> list[str]
     if (disch_w is not None and maint_cap is not None and maint_cap > 0
             and disch_w > maint_cap):
         _LOG.warning(
-            "maintenance_discharge_w %.0f W is above max_w%s %.0f W. Not "
-            "refused - the drain phase SETS the setpoint and the arbiter clamps "
-            "it to %.0f W and names the clamp ('limited by supervised(max_w)'), "
-            "so nothing is silent and the cycle still completes. But it drains "
-            "at %.0f W, not the %.0f W you configured, and the drain phase has "
-            "a 720 min timeout. Lower it to %.0f W or raise max_w to remove the "
-            "surprise.",
-            disch_w, maint_where, maint_cap, maint_cap, maint_cap, disch_w,
-            maint_cap)
+            "maintenance_discharge_w %.0f W is above max_w%s %.0f W, so "
+            "draining runs at %.0f W. Lower it to %.0f W or raise max_w.",
+            disch_w, maint_where, maint_cap, maint_cap, maint_cap)
+        _LOG.debug(
+            "Not refused: the drain phase sets the setpoint, the arbiter "
+            "clamps it to %.0f W and names the clamp, and the drain phase has "
+            "a 720 min timeout.", maint_cap)
 
     return problems
 
@@ -1290,43 +1228,19 @@ def _price_problems(opts: dict) -> list[str]:
         # fall back to, the site has had no tariff at all - a worse state, and
         # one this message must not paper over.
         been_running = (
-            f"the static day/night tariff in static_profile"
+            f"the {S('static_profile')}"
             if str(opts.get("static_profile", "") or "").strip()
-            else "NOTHING AT ALL - static_profile is empty too, so there was "
-                 "no tariff to fall back to either")
+            else "no tariff at all")
         problems.append(
-            f"price_provider is {pid!r}, which WAS a shipped plugin and has "
-            f"been WITHDRAWN (TARIFF-07). This is not a typo and you did not "
-            f"mistype it - the add-on offered this id, accepted it, and has "
-            f"said nothing at every startup since. "
-            f"⚠️ IT HAS NEVER FETCHED A PRICE, HERE OR ANYWHERE: "
-            f"{RETIRED_PROVIDERS[pid]}. Every fetch it ever made ended in "
-            f"SourceUnavailable, and §11.4 turns that into a SILENT fall back "
-            f"- so what this site has actually been running since the day the "
-            f"id was set is {been_running}. Nothing you could see would have "
-            f"differed from a working provider that simply never found a cheap "
-            f"hour, which is why you are being told now rather than left on "
-            f"it. WHAT TO DO: set price_provider to 'generic_dayahead' for the "
-            f"wholesale EPEX BE day-ahead curve, to which the add-on adds your "
-            f"price_markup_eur_kwh and price_taxes_eur_kwh - that APPROXIMATES "
-            f"a Belgian dynamic tariff and cannot reproduce your supplier's "
-            f"B x spot + A formula, so the level will be off even when the "
-            f"shape is right; or 'manual_csv' to enter all-in prices you "
-            f"compute yourself; or 'off' to run on static_profile "
-            f"deliberately. There is deliberately NO alias to your old "
-            f"supplier: aliasing would need your contract's own two "
-            f"coefficients, which live behind your klantenzone login and are "
-            f"in no public index, so the add-on would have to invent the "
-            f"numbers it prices your battery against.")
+            f"{S('price_provider')} is {pid!r}, which was withdrawn and never "
+            f"fetched a price. This site ran on {been_running}. Choose "
+            "'generic_dayahead', 'manual_csv' or 'off'.")
         return problems      # nothing below can be judged against a dead id
 
     if pid != "off" and pid not in PROVIDERS:
         problems.append(
-            f"price_provider is {pid!r}, which is not a shipped plugin. The "
-            f"ids that exist are: off, {', '.join(sorted(PROVIDERS))}. "
-            "Refused rather than defaulted, per the §14 warning box - a "
-            "silent fall back to 'off' would look exactly like a working "
-            "provider that happens never to find a cheap hour.")
+            f"{S('price_provider')} is {pid!r}, which does not exist. Choose "
+            f"one of: off, {', '.join(sorted(PROVIDERS))}.")
         return problems          # nothing below can be judged against an unknown id
 
     # ⚠️ THE HA-SIDE OVERLAP THE PM TOLD US TO DECIDE ABOUT, DECIDED HERE.
@@ -1370,19 +1284,9 @@ def _price_problems(opts: dict) -> list[str]:
                 if str(opts.get(k, "") or "").strip()]
     if pid != "off" and ha_price:
         problems.append(
-            f"price_provider is {pid!r} AND {' and '.join(ha_price)} "
-            f"{'is' if len(ha_price) == 1 else 'are'} set, which is two price "
-            "sources on one site. THE HOME ASSISTANT ENTITIES WIN: they are "
-            "what main.py reduces to the `cheap` flag the maintenance cycle "
-            "reads, and read_inputs() never looks at the other source once "
-            "they are set. The provider series is consumed - "
-            "app/static_tariff.py builds a tariff plan and an arbitrage "
-            "verdict, and app/arbitrage.py trades on it off a background "
-            "refresh - but the `cheap` flag those entities own is a separate "
-            "decision they would silently keep. Clear "
-            "price_now_entity and price_avg_entity to use the "
-            f"{pid!r} plugin, or set price_provider to 'off' to keep the "
-            "Home Assistant sensors.")
+            f"{S('price_provider')} is {pid!r}, but {_labels(ha_price)} would "
+            f"win over it. Clear {'it' if len(ha_price) == 1 else 'them'}, or "
+            "set the source to 'off'.")
 
     # ⚠️ THE SAME RULE FOR THE SOURCE TARIFF-03 ADDED, AND THIS ONE IS A LIVE
     # CONFLICT RATHER THAN A LATENT ONE. main.py's read_inputs() takes `cheap`
@@ -1391,14 +1295,9 @@ def _price_problems(opts: dict) -> list[str]:
     # day/night tariff has no way to see that it lost.
     if ha_price and str(opts.get("static_profile", "") or "").strip():
         problems.append(
-            f"static_profile is set AND {' and '.join(ha_price)} "
-            f"{'is' if len(ha_price) == 1 else 'are'} set, which is two "
-            "tariff sources feeding one cheap-window flag. THE HOME ASSISTANT "
-            "ENTITIES WIN: main.py reads them first and never looks at the "
-            "static profile, so the day/night tariff you typed would decide "
-            "nothing and nothing would say so. Clear price_now_entity and "
-            "price_avg_entity to use static_profile, or clear static_profile "
-            "to keep the Home Assistant sensors.")
+            f"{S('static_profile')} is set, but {_labels(ha_price)} would win "
+            f"over it. Clear the fixed tariff or "
+            f"{'the entity' if len(ha_price) == 1 else 'the two entities'}.")
 
     # ⚠️ THE PROFILE ITSELF, PARSED AT STARTUP RATHER THAN AT 02:00. A profile
     # that does not tile the day has hours with no price, and the only ways to
@@ -1411,7 +1310,7 @@ def _price_problems(opts: dict) -> list[str]:
             profile = parse_static_profile(raw_profile)
         except ProfileInvalid as e:
             profile = None
-            problems.append(f"static_profile cannot be used: {e}")
+            problems.append(f"“{messages.LABELS['static_profile']}” cannot be used. {e}")
         if profile is not None and profile.product is not None \
                 and len(set(profile.prices)) == 1:
             _LOG.info(
@@ -1436,7 +1335,7 @@ def _price_problems(opts: dict) -> list[str]:
         try:
             taxes_table = parse_taxes_profile(raw_taxes_profile)
         except ProfileInvalid as e:
-            problems.append(f"{TAXES_PROFILE_OPTION} cannot be used: {e}")
+            problems.append(f"“{messages.LABELS[TAXES_PROFILE_OPTION]}” cannot be used. {e}")
 
     if taxes_table is not None:
         # ⚠️ TWO WRITERS OF ONE QUANTITY, ONE OF WHICH SILENTLY LOSES - the
@@ -1444,21 +1343,34 @@ def _price_problems(opts: dict) -> list[str]:
         # the price-entity/static_profile pair above. The table decides when it
         # is set, so a non-default scalar left beside it is a number the
         # operator typed that changes nothing, on the quantity §11.4 makes
-        # hardest to notice. It is compared against the SHIPPED DEFAULT rather
+        # hardest to notice. It is compared against the SHIPPED DEFAULTS rather
         # than against presence, because the Supervisor writes every schema key
-        # into the options file whether the operator touched it or not.
+        # into the options file whether the operator touched it or not - so
+        # "the operator did not type this" has to be read off the VALUE.
+        #
+        # ⚠️ TARIFF-18: "UNTOUCHED" IS A SET, NOT ONE NUMBER, AND THE DEFECT
+        # THAT MAKES IT ONE IS AN UPGRADE THAT STOPS A BATTERY CONTROLLER
+        # STARTING. The Supervisor sets `App.options = deepmerge(config.yaml
+        # defaults, stored options)`, so a saved blob carries every schema key
+        # whether the operator typed it or not - the reference install's export
+        # is 70 of 71. When TARIFF-18 moved this default 0.06 -> 0.11736, every
+        # such blob went from "equal to the shipped default" to "not equal to
+        # it" without anybody editing anything, and a site that also carries a
+        # taxes table would have met `SystemExit(78)` on the upgrade. The
+        # sentence below is about a number the OPERATOR TYPED; a superseded
+        # shipped default is not one, so it still reads as untouched. The set
+        # is in price.py beside the default it supersedes, because the two only
+        # ever move together.
         scalar = _number(opts, "price_taxes_eur_kwh",
                          PRICE_OPTION_DEFAULTS["price_taxes_eur_kwh"])
         shipped = PRICE_OPTION_DEFAULTS["price_taxes_eur_kwh"]
-        if scalar is not None and abs(scalar - shipped) > 1e-12:
+        untouched = (shipped,) + tuple(SUPERSEDED_TAXES_DEFAULTS_EUR_KWH)
+        if scalar is not None \
+                and not any(abs(scalar - u) <= 1e-12 for u in untouched):
             problems.append(
-                f"{TAXES_PROFILE_OPTION} is set AND price_taxes_eur_kwh is "
-                f"{scalar} rather than its shipped {shipped}. THE TABLE WINS: "
-                f"the add-on reads the per-period figures and never looks at "
-                f"the scalar, so the number you typed there would decide "
-                f"nothing and nothing would say so. Set price_taxes_eur_kwh "
-                f"back to {shipped}, or clear {TAXES_PROFILE_OPTION} to keep "
-                f"the flat figure.")
+                f"{S(TAXES_PROFILE_OPTION)} is set, so "
+                f"{S('price_taxes_eur_kwh')} is not used. Set it back to "
+                f"{shipped} from {scalar}, or clear the table.")
 
         # ⚠️ THE UNITS RUNG, AND IT IS A SECOND QUANTITY RATHER THAN A
         # RESTATEMENT. Every Belgian DSO prints these bands in c EUR/kWh
@@ -1473,13 +1385,8 @@ def _price_problems(opts: dict) -> list[str]:
                         if abs(p.eur_per_kwh) >= 1.0})
         if steep:
             problems.append(
-                f"{TAXES_PROFILE_OPTION} carries {steep} EUR/kWh. Belgian "
-                f"levies and distribution run about 0.05-0.25 EUR/kWh, so "
-                f"these are almost certainly the CENT figures off the tariff "
-                f"card (ORES prints `13,27`, which is 0.1327 EUR/kWh) typed "
-                f"without the conversion - a factor of 100 that would make "
-                f"every hour look like an emergency. Divide by 100, or clear "
-                f"the option.")
+                f"{S(TAXES_PROFILE_OPTION)} has {steep} EUR/kWh, which looks "
+                "like cents. Divide the figures by 100, or clear this setting.")
         negative = sorted({p.eur_per_kwh for p in taxes_table.periods
                            if p.eur_per_kwh < 0})
         if negative:
@@ -1490,10 +1397,9 @@ def _price_problems(opts: dict) -> list[str]:
             # observe. §14's warning box governs CONTRADICTIONS, and this is
             # not one.
             _LOG.warning(
-                "%s carries negative levies %s EUR/kWh. That is accepted, but "
-                "a tax component below zero is usually a sign error: the "
-                "add-on will SUBTRACT it from the published price in those "
-                "hours.", TAXES_PROFILE_OPTION, negative)
+                "%s has negative levies %s EUR/kWh, which are subtracted from "
+                "the price. This is allowed, but it is usually a sign error.",
+                TAXES_PROFILE_OPTION, negative)
 
     # ⚠️ TARIFF-15: THE FORMULA, GRADED AGAINST THE OPERATOR'S OWN CARD, AT
     # STARTUP RATHER THAN AT 03:00.
@@ -1523,30 +1429,21 @@ def _price_problems(opts: dict) -> list[str]:
     # CARD AGAINST REALITY. A consistent-but-wrong pair - both numbers off the
     # wrong product - reproduces its own printed price and passes. Nothing can
     # catch that.
+    spec = None                 # TARIFF-16 reads this back, below
     raw_formula = opts.get("price_formula", "")
     has_formula = bool(str(raw_formula or "").strip()) \
         or isinstance(raw_formula, dict)
     if pid == "custom_formula" and not has_formula:
         problems.append(
-            "price_provider is 'custom_formula' but price_formula is empty, "
-            "so the add-on has no coefficients to price anything with. Every "
-            "fetch would return no-price-data and §11.4 would fall back "
-            "silently - which is the shape of defect this provider exists to "
-            "remove, arrived at by leaving one field blank. Copy the "
-            "Tariefformule line off your supplier's tariff card, e.g. "
-            "{\"index\":\"epex_be\",\"resolution\":\"hourly\","
-            "\"factor\":0.102,\"offset\":1.00,"
-            "\"units\":\"c_eur_per_kwh\",\"vat_pct\":6,"
-            "\"card\":{\"month\":\"2026-09\","
-            "\"index_eur_per_mwh\":133.9905,\"expect_incl_vat\":15.55}} "
-            "- see DOCS.md. Or set price_provider to 'generic_dayahead' for "
-            "the wholesale curve with a flat markup.")
+            f"{S('price_provider')} is 'custom_formula', but "
+            f"{S('price_formula')} is empty. Copy the formula from your "
+            "supplier's tariff card, or choose 'generic_dayahead'.")
     elif has_formula:
         try:
             spec = parse_price_formula(raw_formula)
         except FormulaInvalid as e:
             spec = None
-            problems.append(f"price_formula cannot be used: {e}")
+            problems.append(f"“{messages.LABELS['price_formula']}” cannot be used. {e}")
         if spec is not None and pid != "custom_formula":
             # ⚠️ A WARNING AND NOT A REFUSAL. This is not two price sources
             # fighting over one flag - it is one that is simply not wired to
@@ -1555,11 +1452,9 @@ def _price_problems(opts: dict) -> list[str]:
             # silent loser this module's case (a) is about, so it is said out
             # loud rather than left to be discovered from a bill.
             _LOG.warning(
-                "price_formula is filled in but price_provider is %r, so the "
-                "coefficients decide NOTHING - only 'custom_formula' reads "
-                "them. Set price_provider to 'custom_formula' to use them, or "
-                "clear price_formula so the configuration says what the "
-                "add-on is doing.", pid)
+                "price_formula is filled in, but price_provider is %r, so the "
+                "formula is not used. Set price_provider to 'custom_formula' "
+                "or clear price_formula.", pid)
         if spec is not None and pid == "custom_formula":
             taxes = _number(opts, "price_taxes_eur_kwh",
                             PRICE_OPTION_DEFAULTS["price_taxes_eur_kwh"])
@@ -1574,6 +1469,97 @@ def _price_problems(opts: dict) -> list[str]:
                 # cannot start.
                 _LOG.warning("%s", aged)
 
+    # ⚠️ TARIFF-16: THE INJECTION LEG, REFUSED AT STARTUP ON THE SAME RULE.
+    #
+    # THE DEFECT THIS EXISTS TO PREVENT: `export_price_eur_kwh` models
+    # injection as ONE scalar, and the published market is a line -
+    # Eneco `0,1 x BELPEX-H - 1,188` c EUR/kWh, "het injectietarief is
+    # dynamisch en kan per uur wijzigen", identical on the January and the
+    # September 2026 cards. A scalar cannot hold its own factor (0,100 against
+    # 0,102 on the same supplier's consumption leg), cannot hold a negative
+    # offset, cannot state that injection is VAT-EXEMPT while consumption is
+    # at 6%, and cannot go below zero in the midday hours a PV household
+    # actually exports in.
+    #
+    # ⚠️ AND WHAT IT DOES NOT AFFECT TODAY, said here rather than left to be
+    # inferred: `arbitrage.py` does not read the injection price at all. Both
+    # hours it compares are all-in CONSUMPTION prices, by its own
+    # accounting-basis comment. No trade turns on this option. What it changes
+    # is what the operator is told and what a future export-aware strategy
+    # rests on - which is why it is validated here rather than trusted.
+    raw_export = opts.get(EXPORT_FORMULA_OPTION, "")
+    has_export = bool(str(raw_export or "").strip()) \
+        or isinstance(raw_export, dict)
+    if has_export:
+        try:
+            xspec = parse_export_formula(raw_export)
+        except FormulaInvalid as e:
+            xspec = None
+            problems.append(f"“{messages.LABELS[EXPORT_FORMULA_OPTION]}” cannot be used. {e}")
+        if xspec is not None:
+            # ⚠️ THE 6% ASYMMETRY, PRINTED RATHER THAN ASSUMED. The two legs
+            # carry INDEPENDENT `vat_pct` values and a Belgian site's are 6 and
+            # 0. Printing both beside each other is the only place an operator
+            # can see that the add-on knows it - a status page shows one price
+            # and no arithmetic.
+            _LOG.info(
+                "%s is set: injection priced as (%g x index %+g) x "
+                "(1 + %g/100) %s, i.e. %.4g x the wholesale price with a "
+                "%+.5f EUR/kWh offset. ⚠️ NO STRATEGY IN THIS ADD-ON READS "
+                "IT: arbitrage.py prices the sell side as displaced IMPORT "
+                "and compares two all-in CONSUMPTION prices, so this option "
+                "changes no decision the add-on takes today. It is what you "
+                "are shown, and the shape a future export-aware strategy "
+                "would read.",
+                EXPORT_FORMULA_OPTION, xspec.factor, xspec.offset,
+                xspec.vat_pct, xspec.units, xspec.passthrough,
+                xspec.offset_eur_kwh)
+            if spec is not None:
+                # ⚠️ THE ASYMMETRY, AS AN ORDERED PAIR RATHER THAN TWO NUMBERS
+                # IN ONE SENTENCE (MUTATION.md habit 14). "6 and 0 appear
+                # somewhere" is satisfied by the two legs transposed, which is
+                # the sentence telling an operator that the add-on has their
+                # VAT treatment exactly backwards.
+                _LOG.info(
+                    "the two legs are priced independently: consumption "
+                    "factor %g at vat_pct %g, injection factor %g at vat_pct "
+                    "%g. In Belgium those differ - \"injectietarieven zijn "
+                    "vrijgesteld van btw\" while consumption is at 6%% - and "
+                    "%s is the option that makes the difference "
+                    "expressible; a single scalar could not state it.",
+                    spec.factor, spec.vat_pct, xspec.factor, xspec.vat_pct,
+                    EXPORT_FORMULA_OPTION)
+            if not xspec.card_graded:
+                # ⚠️ A WARNING AND NEVER A REFUSAL, AND THE GAP IS NAMED
+                # RATHER THAN WORKED AROUND. `price_formula`'s card block is
+                # required because a Belgian card prints the consumption
+                # formula, the reference index AND the resulting price. Eneco's
+                # INJECTION formula is printed with no price beside it, so on
+                # that card there is nothing to reproduce. Requiring a block
+                # here would make the market's own published line
+                # inexpressible; inventing the estimate would grade the
+                # coefficients against arithmetic done with the same
+                # coefficients. So the leg is accepted, the two coefficient
+                # bounds in `implausible_injection()` are applied, and the
+                # operator is told which of the two checks did NOT run.
+                _LOG.warning(
+                    "%s has no \"card\" block, so its numbers are not checked "
+                    "against a printed price, only their shape (pass-through "
+                    "%.4g, offset %+.5f EUR/kWh).",
+                    EXPORT_FORMULA_OPTION, xspec.passthrough,
+                    xspec.offset_eur_kwh)
+                _LOG.debug(
+                    "Accepted because some suppliers (Eneco) print the "
+                    "injection formula with no price beside it. If your card "
+                    "prints an injection estimate, add {\"month\": ..., "
+                    "\"index_eur_per_mwh\": ..., \"expect_incl_vat\": ...} "
+                    "and the add-on refuses to start unless your numbers "
+                    "reproduce it.")
+            else:
+                xaged = stale_card(xspec)
+                if xaged:
+                    _LOG.warning("%s", xaged)
+
     # ⚠️ A WARNING, NOT A REFUSAL, AND THE ASYMMETRY IS DELIBERATE. §11.4 says a
     # site with no price data falls back to the static profile; a dynamic site
     # with none configured has nothing to fall back to when its feed dies. That
@@ -1581,11 +1567,9 @@ def _price_problems(opts: dict) -> list[str]:
     # every install TARIFF-02 shipped, none of which could have had one.
     if pid != "off" and not str(opts.get("static_profile", "") or "").strip():
         _LOG.warning(
-            "price_provider is %r but static_profile is empty. §11.4's "
-            "degradation row is 'no price data -> fall back to the static "
-            "profile'; with none configured, a feed outage leaves this site "
-            "with no tariff at all rather than with a coarse one. Not refused, "
-            "but filling it in is what makes that row work.", pid)
+            "price_provider is %r but static_profile is empty, so a price "
+            "feed outage leaves no tariff at all. Fill in static_profile as a "
+            "fallback.", pid)
 
     # ⚠️ OPT-04. THE THREE WAYS `arbitrage_enabled: true` CAN BE A LIE, refused
     # rather than logged, because a strategy that is armed in the UI and cannot
@@ -1600,62 +1584,39 @@ def _price_problems(opts: dict) -> list[str]:
                      PRICE_OPTION_DEFAULTS["cycle_cost_threshold_eur"])
     if thresh is None or thresh < 0:
         problems.append(
-            f"cycle_cost_threshold_eur is "
-            f"{opts.get('cycle_cost_threshold_eur')!r} and must be a "
-            f"non-negative number of EUR/kWh - it is what one round trip COSTS "
-            f"(§10.1). A negative threshold is one that every spread clears, "
-            f"including a spread of nothing, which is arbitrage with the brake "
-            f"removed rather than arbitrage tuned aggressively.")
+            f"{S('cycle_cost_threshold_eur')} is "
+            f"{messages.shown(opts.get('cycle_cost_threshold_eur'))}. Set it to 0 or more, "
+            "in EUR/kWh.")
 
     if arbitrage_on(opts):
         if pid == "off" and not str(opts.get("static_profile", "") or "").strip():
             problems.append(
-                "arbitrage_enabled is on but price_provider is 'off' and "
-                "static_profile is empty, so this site has NO PRICES AT ALL. "
-                "§10.1's priority 3 is 'charge cheap, discharge expensive' and "
-                "there is nothing here to tell cheap from expensive, so the "
-                "strategy would refuse on every cycle forever while the "
-                "configuration said it was running. Configure a price_provider "
-                "or a static_profile, or turn arbitrage_enabled off.")
+                f"{S('arbitrage_enabled')} is on, but the site has no prices. "
+                f"Set {_labels(['price_provider', 'static_profile'], 'or')}, "
+                "or turn trading off.")
         if not is_enabled(opts):
             problems.append(
-                "arbitrage_enabled is on but meter_source is 'off', so there "
-                "is no P1 telegram stream, the capacity-tariff peak guard "
-                "never runs, and nothing measures the 15-minute average this "
-                "strategy's charging would land in. §9.1 gives peak shaving "
-                "priority over arbitrage; an unmeasured peak cannot be shaved, "
-                "so arbitrage would be deliberately creating the billed "
-                "quantity with the one guard that limits it switched off. "
-                "app/arbitrage.py refuses to trade in that state anyway - this "
-                "refuses the configuration that asks it to. Set meter_source, "
-                "or turn arbitrage_enabled off.")
+                f"{S('arbitrage_enabled')} is on, but no meter is set in "
+                f"{S('meter_source')}. Choose a meter, or turn trading off.")
         floor = _number(opts, "arbitrage_soc_floor",
                         PRICE_OPTION_DEFAULTS["arbitrage_soc_floor"])
         ceiling = _number(opts, "arbitrage_soc_ceiling",
                           PRICE_OPTION_DEFAULTS["arbitrage_soc_ceiling"])
         if floor is None or ceiling is None:
             problems.append(
-                f"arbitrage_soc_floor {opts.get('arbitrage_soc_floor')!r} and "
-                f"arbitrage_soc_ceiling {opts.get('arbitrage_soc_ceiling')!r} "
-                f"must both be numbers - they are percentages of pack charge.")
+                f"{S('arbitrage_soc_floor')} and {S('arbitrage_soc_ceiling')} "
+                "must both be numbers, in %.")
         elif floor >= ceiling:
             problems.append(
-                f"arbitrage_soc_floor is {floor:g} % and arbitrage_soc_ceiling "
-                f"is {ceiling:g} %, so there is no band left between them: "
-                f"every state of charge is either at or under the floor (no "
-                f"discharge) or at or over the ceiling (no charge), and the "
-                f"strategy can never act. The floor is the reserve it may not "
-                f"spend and the ceiling is the headroom it may not overfill, "
-                f"so the floor must be the SMALLER number.")
+                f"{S('arbitrage_soc_floor')} is {floor:g} %, not below "
+                f"{S('arbitrage_soc_ceiling')} at {ceiling:g} %. Make the lower "
+                "limit the smaller number.")
 
     if pid == "manual_csv" and not str(opts.get("price_csv_path", "") or "").strip():
         problems.append(
-            "price_provider is 'manual_csv' but price_csv_path is empty, so "
-            "the offline fallback has no file to read. Every fetch would "
-            "return no-price-data with a filesystem error as its reason - "
-            "which is §11.4 behaviour arrived at by accident rather than by "
-            "configuration. Point it at the CSV, or set price_provider to "
-            "'off', which says the same thing on purpose.")
+            f"{S('price_provider')} is 'manual_csv', but "
+            f"{S('price_csv_path')} is empty. Set the path to the CSV file, or "
+            "choose 'off'.")
 
     return problems
 
@@ -1681,11 +1642,9 @@ def refuse(problems: list[str]) -> None:
     at all and even the exit status distinguishes the two.
     """
     _LOG.error("=" * 72)
-    _LOG.error("REFUSING TO START: the add-on configuration is not usable.")
-    _LOG.error("This is a CONFIGURATION problem, not a crash. Nothing is broken;")
-    _LOG.error("the add-on will start as soon as the settings below are fixed.")
-    _LOG.error("Fix them in Settings > Add-ons > GoodWe RS485 Controller >")
-    _LOG.error("Configuration, then start the add-on again.")
+    _LOG.error("The add-on did not start, because its settings have problems.")
+    _LOG.error("Nothing is broken. Fix the settings below, then start it again.")
+    _LOG.error("They are on the add-on's Configuration tab.")
     _LOG.error("-" * 72)
     for i, problem in enumerate(problems, 1):
         _LOG.error("  %d. %s", i, problem)

goodwe_controller/app/web.py

@@ -31,7 +31,7 @@ import logging
 
 from aiohttp import web
 
-from . import selfconfig
+from . import messages, selfconfig
 from .config_page import CONFIG_PAGE
 from .configui import changed_keys, field_model, problems_by_field
 
@@ -125,11 +125,8 @@ refresh(); setInterval(refresh, 3000);
 # them too, and says so, because a green page that is green for a reason the
 # operator cannot see is the exact failure this add-on keeps refusing to ship.
 DEVICE_NOTE = (
-    "%s did not report a range, so the two checks that compare a configured "
-    "ceiling against what the device itself accepts were skipped - here and at "
-    "startup, identically. Everything else was checked. If the device answers "
-    "later and disagrees, the add-on refuses to start then, with the same "
-    "message you would have seen here.")
+    "%s did not report its power range, so two checks were skipped, here and "
+    "at start. If they fail later, the add-on will not start then.")
 
 
 def build_app(controller, selfcfg=None) -> web.Application:
@@ -264,7 +261,8 @@ def build_app(controller, selfcfg=None) -> web.Application:
             _LOG.error("saving options failed: %s", err)
             return web.json_response({"error": str(err)}, status=502)
         controller.log_event("configuration saved from the panel - "
-                             "not applied until the add-on restarts")
+                             "not applied until the add-on restarts",
+                             hint=messages.hint("settings_saved"))
         return web.json_response({"ok": True, **result})
 
     async def config_restart(request):
@@ -288,7 +286,8 @@ def build_app(controller, selfcfg=None) -> web.Application:
         except selfconfig.SupervisorUnavailable as err:
             _LOG.error("restart request failed: %s", err)
             return web.json_response({"error": str(err)}, status=502)
-        controller.log_event("restart requested from the configuration panel")
+        controller.log_event("restart requested from the configuration panel",
+                             hint=messages.hint("restart_requested"))
         return web.json_response({"ok": True})
 
     app = web.Application()

goodwe_controller/config.yaml

@@ -1,5 +1,5 @@
 name: GoodWe RS485 Controller
-version: "0.9.0"
+version: "0.12.0"
 slug: goodwe_controller
 description: >-
   Drives a GoodWe ES/BP battery inverter over RS485 by emulating its smart
@@ -93,7 +93,7 @@ options:
   # against a sibling's numbers; an entry silently inheriting `soc_entity` would
   # rebuild that defect in YAML. `name`, `setpoint_entity`, `max_w` and
   # `bms_soc_floor` are therefore REQUIRED of every entry (the schema below enforces it, and
-  # validate.py rule 9 enforces it again for the callers the Supervisor never
+  # validate.py rules 8 and 9 enforce it again for the callers the Supervisor never
   # sees). An omitted `soc_entity`/`batt_entity` means THIS UNIT HAS NO SUCH
   # SENSOR - `inputs_ok` already stops the site for that - and never means
   # "use the other one's".
@@ -147,6 +147,76 @@ options:
   inverters: []
   estop_fitted: false
 
+  # TEL-11 - THE SITE'S PV PRODUCTION, IN WATTS, AND IT IS READ BY NOTHING THAT
+  # DECIDES ANYTHING. Optional, empty on every install that does not set it, and
+  # when it is empty the add-on reads no entity, announces no entity, publishes
+  # no topic and shows no status row.
+  #
+  # ⚠️ AN HA ENTITY AND NOT A REGISTER, BECAUSE MOST SOLAR INVERTERS ARE NOT ON
+  # THIS BUS. The RS485 bus this add-on speaks carries the BATTERY inverter it
+  # drives; a household's PV inverter is normally a different box from a
+  # different vendor, reporting into Home Assistant through its own integration.
+  # So this takes whatever `sensor.*` the site's PV integration provides, any
+  # brand Home Assistant can read.
+  #
+  # POSITIVE IS PRODUCTION. An entity that reads the other way round goes in
+  # `pv_invert_entities` below - see DECISIONS/TEL-14-pv-sign.md.
+  #
+  # ⚠️ THE ENTITY'S OWN `unit_of_measurement` IS WHAT IS BELIEVED - W, kW, MW
+  # and the rest of Home Assistant's power units. A sensor with no unit, or with
+  # a unit that is not power, is REFUSED and the status page says which: there
+  # is no magnitude heuristic that can tell 30 W of dusk from 30 kW of noon, and
+  # a factor of 1000 in the one channel that exists to be believed a week later
+  # is worse than a refusal an operator can read.
+  pv_entity: ""
+
+  # TEL-12 - THE SAME CHANNEL WHEN THE ROOF HAS SEVERAL INVERTERS, WHICH IS THE
+  # ORDINARY CASE AND NOT AN EDGE ONE. A multi-string or multi-orientation roof
+  # routinely carries two or three PV inverters, each publishing its own power
+  # sensor; 0.11.0 shipped `pv_entity` as a single string and the reference
+  # site's owner reported within minutes that they could configure one of
+  # theirs. List them all here and the row carries the SITE total.
+  #
+  # ⚠️ DECLARED, THIS REPLACES `pv_entity` - it does not extend it. Set both and
+  # ONLY this list is read, and the status page says so. That is CFG-04's rule
+  # for `inverters:` applied to the upgrade path this key exists for: the
+  # install being upgraded HAS `pv_entity` set, and an operator who adds all
+  # their inverters to this list while the old key still names one of them would
+  # DOUBLE that inverter under a union rule. Clear `pv_entity` when you fill
+  # this in.
+  #
+  # ⚠️ AND IF ANY ONE OF THEM IS NOT REPORTING, THERE IS NO SITE TOTAL - the row
+  # publishes `unknown` and the recorder records a GAP. It does NOT publish the
+  # sum of the ones that answered: two of three inverters add up to a smaller
+  # number that is indistinguishable from a real one, and a week later that
+  # reads as "there was less sun than there was" - the exact conclusion this
+  # channel exists to TEST rather than to manufacture. The status page names
+  # which entity is missing and why, and lists what the others reported, because
+  # a human reading it live wants the diagnostic; the recorded number does not,
+  # because nobody re-derives a week of history. See
+  # DECISIONS/TEL-12-several-pv-inverters.md.
+  #
+  # ⚠️ THE FIX IS NOT A TEMPLATE SENSOR THAT SUMS THEM. You may legitimately
+  # prefer one, but a template sensor summing an `unavailable` source yields the
+  # partial total silently - the same defect one layer down, in a place this
+  # add-on cannot see or report.
+  #
+  #   pv_entities:
+  #     - sensor.pv_east_power
+  #     - sensor.pv_west_power
+  #     - sensor.pv_garage_power
+  #
+  # Each entity's OWN `unit_of_measurement` is read, so a kW inverter beside a W
+  # one sums correctly. Empty is the shipped default and means "use `pv_entity`,
+  # which is also empty" - i.e. no PV channel at all, which is every install.
+  pv_entities: []
+
+  # TEL-14. Every PV entity listed here (in `pv_entity` or `pv_entities`) has
+  # its sign flipped, for a kWh meter or power clamp that reads production as
+  # negative. Per entity, because one roster can mix both conventions. `[]` is
+  # load-bearing like `pv_entities: []`; see DECISIONS/TEL-14-pv-sign.md.
+  pv_invert_entities: []
+
   # ==========================================================================
   # METER - where the grid reading comes from
   # ==========================================================================
@@ -156,7 +226,7 @@ options:
   # ha_signed reads ONE signed HA entity (+ import / - export), which is what a
   # HomeWizard P1 publishes and what ha_dsmr cannot consume.
   # homewizard_local skips Home Assistant entirely and polls the meter's own
-  # local API. ⚠️ It is the ONLY mode whose sensor.p1_sample_age_s measures when
+  # local API. ⚠️ It is the ONLY mode whose sensor.goodwe_p1_sample_age measures when
   # the meter REPORTED rather than when the value last CHANGED - HA emits
   # nothing at all for a repeated reading - so it is the only mode a firmware
   # watchdog may threshold. See DOCS.md.
@@ -291,13 +361,58 @@ options:
   # price_markup_eur_kwh is ignored under it, with a line in the log saying so.
   price_provider: "off"
   price_markup_eur_kwh: 0.03
-  price_taxes_eur_kwh: 0.06
+
+  # TARIFF-18. The all-in Flemish non-energy figure, EUR/kWh, incl. 6 % VAT.
+  # Its components are named in app/price.py's FLEMISH_TAXES_COMPONENTS_EUR_KWH
+  # and test_price.py section 1b re-adds them:
+  #
+  #   Fluvius distribution (Antwerpen)              5,35  c EUR/kWh
+  #   Bijzondere accijns, "Alle verbruik"           4,876
+  #   Bijdrage groene stroom en WKK Vlaanderen      1,51
+  #   Energiebijdrage (0 EUR/MWh since 2026-08-01)  0
+  #                                                ------
+  #                                                11,736 c EUR/kWh = 0.11736
+  #
+  # ⚠️ THIS IS PER-DSO AND YOURS IS PROBABLY DIFFERENT. Only the distribution
+  # row moves: across the eight Fluvius DSOs it runs 5,28 c EUR/kWh
+  # (Midden-Vlaanderen) to 6,70 (West), so the Flemish total runs about 0.117
+  # to 0.131. Antwerpen is near the LOW end, which is the direction this
+  # default should err in - it is inert on which hour is cheapest, but §17's
+  # negative-price guard reads the ABSOLUTE all-in price, and a figure set too
+  # high would carry a genuinely negative hour above zero.
+  #
+  # ⚠️ WALLONIA AND BRUSSELS DO NOT BELONG IN THIS SCALAR AT ALL. Their
+  # distribution tariff has a day and a night band; use price_taxes_profile.
+  price_taxes_eur_kwh: 0.11736
 
   # §9.3: injection is priced SEPARATELY, and in Belgium it is often near zero -
-  # which by itself strongly favours self-consumption over export. A scalar, not
-  # a second series: no shipped supplier publishes a dynamic injection curve.
+  # which by itself strongly favours self-consumption over export. This is the
+  # FLAT injection price, for a site paid the same for every exported kWh.
+  #
+  # ⚠️ THE REASON THIS COMMENT USED TO GIVE - "no shipped supplier publishes a
+  # dynamic injection curve" - WAS FALSE, and TARIFF-07 struck the same
+  # sentence from app/price.py and DOCS.md without reaching this file. Eneco
+  # publishes `0,1 x BELPEX-H - 1,188` c EUR/kWh on the same card as its
+  # consumption formula, ENGIE publishes `(B x eSpot_15) - A`, and Aspiravi
+  # `0,07 x Belpex - 2`. A site on one of those sets price_export_formula
+  # below; this scalar stays the fixed-product default and is what every site
+  # uses today.
   export_price_eur_kwh: 0.04
 
+  # TARIFF-16. The INJECTION leg as a formula, in price_formula's own grammar
+  # and with its OWN coefficients: Eneco uses 0,102 on consumption and 0,100 on
+  # injection, and injection is VAT-EXEMPT where consumption is at 6%, so
+  # `vat_pct` here is normally 0. A negative `offset` is expected - it is what
+  # the published lines carry - and the resulting price legitimately goes below
+  # zero in the midday hours a PV household exports in.
+  #
+  # ⚠️ NO STRATEGY IN THIS ADD-ON READS IT. arbitrage.py prices the sell side
+  # as displaced IMPORT and compares two all-in CONSUMPTION prices; it does not
+  # read the injection price at all. This option is what the operator is shown
+  # and the shape a future export-aware strategy would rest on. Empty by
+  # default, which leaves every existing site on the scalar above.
+  price_export_formula: ""
+
   # §14's `tariffs.static_profile`, and "" is its `null`. §9.2: "a large share
   # of the installed base is on [a static profile]" - this is what makes those
   # sites first-class rather than "price_provider: off, good luck".
@@ -359,7 +474,10 @@ options:
   #
   # ⚠️ SET THIS *OR* price_taxes_eur_kwh, NOT BOTH. Two writers of one quantity,
   # one of which silently wins, is refused at startup: leave the scalar at its
-  # shipped default when you fill this in.
+  # shipped default when you fill this in. A scalar still sitting on the
+  # SUPERSEDED 0.06 is accepted too (TARIFF-18 moved that default, and your
+  # stored options carry the old number whether you typed it or not) - the
+  # refusal is about a figure you chose, not about one this add-on wrote.
   price_taxes_profile: ""
 
   # TARIFF-15. YOUR OWN TARIFF CARD, as two fixed coefficients. Used only when
@@ -698,6 +816,38 @@ options:
   # and not 150 or 200. 37 control cycles.
   delivery_hold_s: 185
 
+  # SAFETY-10. Run the whole decision path and command NOTHING - strategies,
+  # arbiter, clamps and guards all run, the decision and its reason are
+  # recorded, and every inverter is held at 0 W. `app/shadow.py` carries the
+  # argument; the three things to know before changing this line are:
+  #
+  #   auto  shadow WHILE CONTROL IS STOPPED, live once it is started. This is
+  #         the shipped value and it is what "default-on" means here.
+  #   on    always shadow, whatever the Start / stop button says. This is the
+  #         one an operator picks to watch a day of decisions on an armed site
+  #         before letting it trade.
+  #   off   ordinary control.
+  #
+  # ⚠️ IT IS NOT A BOOLEAN DEFAULTING TO `true`, AND THAT IS THE WHOLE CARD.
+  # The Supervisor composes an add-on's options as `{**these defaults, **the
+  # stored user options}`, so a NEW key with a new default reaches every
+  # EXISTING install on the next update - including one regulating a real
+  # battery. `shadow_mode: true` would silently stop it, and the only symptom
+  # would be a battery that has stopped doing anything. There is no mechanism
+  # in this options system that lets one key default differently for a new
+  # install and an existing one, so "default-on for new" has to be a value the
+  # add-on RESOLVES. `auto` is that value: a fresh install ships
+  # `auto_start: false` and therefore comes up in shadow mode; an install that
+  # is controlling is started, so `auto` resolves to live and NOTHING about it
+  # changes.
+  #
+  # ⚠️ AND UNDER `auto` THE START BUTTON LEAVES SHADOW MODE. Pressing *Start /
+  # stop control* is the operator saying "control the battery". Somebody who
+  # wants the decisions recorded WHILE the loop runs sets `on` explicitly -
+  # which is the configuration this option exists for, and the one that cannot
+  # be reached by accident.
+  shadow_mode: "auto"
+
   # ==========================================================================
   # ADVANCED - the control law and diagnostics
   # ==========================================================================
@@ -768,12 +918,13 @@ schema:
   # batteries, whereas an absent capacity has an honest answer - no opinion
   # about the split, every unit weighs 1.0, which is what shipped.
   #
-  # ⚠️ THREE KEYS ARE REQUIRED PER ENTRY AND THAT IS DELIBERATE. An entry with
+  # ⚠️ FOUR KEYS ARE REQUIRED PER ENTRY AND THAT IS DELIBERATE. An entry with
   # no `name` has no Store namespace and would share another unit's SAFETY-02
   # latch; one with no `setpoint_entity` is a unit nothing can command; one with
   # no `max_w` would have to borrow a rating, which is the sibling-grading
-  # defect DEV-02 removed. The optional pair is the sensors, whose absence
-  # honestly means "this unit reports none".
+  # defect DEV-02 removed; `bms_soc_floor` is SAFETY-32's (options block above).
+  # The optional keys are the sensors, whose absence honestly means "this unit
+  # reports none", and `capacity_kwh`.
   #
   # ⚠️ THIS BLOCK IS DECLARED BEFORE `max_w:` ON PURPOSE. `max_w` now appears
   # TWICE under `schema:` - once nested here, once flat below - and a reader
@@ -792,6 +943,41 @@ schema:
       capacity_kwh: float(0.1,200)?
 
   estop_fitted: bool
+  # TEL-11. Optional, and OPTIONAL WITHOUT A COMPANION RULE - unlike
+  # `price_now_entity`/`price_avg_entity`, which are legal only while
+  # `price_provider` is `off` and make the add-on REFUSE TO START otherwise.
+  # Nothing in validate.py mentions this key: it cannot conflict with anything,
+  # because nothing else reads it.
+  pv_entity: str?
+
+  # TEL-12. ⚠️ A SECOND KEY RATHER THAN A LIST SHAPE ON `pv_entity`, AND THAT IS
+  # A MEASUREMENT AND NOT A PREFERENCE. `pv_entity` shipped in 0.11.0 as `str?`
+  # and the reference site has a string persisted in it. Declared as a list,
+  # Supervisor 2026.08.0 answers that stored string with
+  #
+  #   Invalid list for option 'pv_entity' in GoodWe RS485 Controller
+  #
+  # and `deepmerge`'s list strategy is `override`, so a shipped `[]` default does
+  # NOT rescue it - the operator's string stands and is refused. That is CFG-04
+  # §B's trap in the other direction: an add-on that will not start, and the
+  # schema needed to fix it pinned to the version that cannot be installed. The
+  # only single-key spelling Supervisor accepts for BOTH shapes is `match(.*)?`,
+  # which validates nothing at all (it admits a number, a dict, any list of
+  # anything) and renders as a plain text box. Measured, both of them, by
+  # `tools/supervisor_shape_probe.py` §G - the transcript is in
+  # DECISIONS/TEL-12-several-pv-inverters.md §1.
+  #
+  # ⚠️ AND `pv_entities: []` IN THE `options:` BLOCK IS LOAD-BEARING, exactly as
+  # `inverters: []` is. §G measures the same isolated counterfactual: the
+  # shipped defaults MINUS only this key are refused with `Missing option
+  # 'pv_entities' in root`, which is every options blob written before 0.12.
+  # `p1_phase_import_entities` is the shipped precedent for the pair.
+  pv_entities:
+    - str
+  # TEL-14. A parallel list, not a prefix or a dict: measured by
+  # tools/supervisor_shape_probe.py section H, DECISIONS/TEL-14-pv-sign.md.
+  pv_invert_entities:
+    - str
 
   # ==========================================================================
   # METER - where the grid reading comes from
@@ -876,6 +1062,15 @@ schema:
   # bottoms out at 0 would make that site inexpressible.
   export_price_eur_kwh: float(-1,1)
 
+  # TARIFF-16. A JSON string in `price_formula`'s grammar, parsed by
+  # `custom_formula.parse_export_formula()` - the SAME parser with its option
+  # name as an argument, so a second unit table and a second card rule do not
+  # exist to diverge. The `card` block is OPTIONAL on this leg and required on
+  # the other: Eneco prints its injection formula with no price beside it, so
+  # on that card there is nothing to grade against, and the add-on says at
+  # startup that the leg is ungraded rather than inventing an estimate.
+  price_export_formula: str?
+
   # A JSON string rather than a nested schema, deliberately: it is ONE option
   # key (§14 has one), it survives config.yaml's flat options block, and
   # parse_static_profile() accepts an already-parsed dict too, so a future
@@ -1008,6 +1203,15 @@ schema:
   # running short of one unit's share must be reported well inside one.
   delivery_hold_s: int(30,900)
 
+  # SAFETY-10. ⚠️ A THREE-VALUED LIST AND NOT A `bool`, for the reason written
+  # against the default in the options block above: a boolean has one default
+  # and the Supervisor gives it to every install, new and existing alike.
+  # `app/shadow.MODES` is this tuple and `validate.py` rule 11 refuses anything
+  # else BY NAME, because `shadow.mode()` resolves an unreadable value to
+  # SHADOW - safe, but a silent reinterpretation that commands nothing for as
+  # long as nobody notices.
+  shadow_mode: list(auto|on|off)
+
   # ==========================================================================
   # ADVANCED - the control law and diagnostics
   # ==========================================================================

goodwe_controller/named_absence.py

@@ -0,0 +1,99 @@
+"""Read a value a check prints or grades without raising (TEST-26).
+
+Each test file is one script, so an IndexError in a print or a check name
+kills every check after it (MUTATION.md, FCST-06). Read through these instead,
+and conjoin `present(x)` in the check so the absence grades as a named FAIL.
+
+`ABSENT` values never raise: they format as `<ABSENT ...>` under any spec,
+index and attribute to themselves, compare unequal AND not-unequal, and are
+falsy. `not x`, `"a" not in x` and `all(... for _ in x)` are therefore TRUE of
+one, which is why the check needs the `present()` term. `int()`, `range()` and
+use as a list index still raise: guard those with `present()`.
+"""
+
+_NAN = float("nan")
+
+
+class Absent:
+    __slots__ = ("what",)
+
+    def __init__(self, what):
+        object.__setattr__(self, "what", what)
+
+    def __repr__(self):
+        return f"<ABSENT {self.what}>"
+
+    __str__ = __repr__
+
+    def __format__(self, spec):
+        return repr(self)
+
+    def __bool__(self):
+        return False
+
+    def __eq__(self, other):
+        return False
+
+    __ne__ = __lt__ = __le__ = __gt__ = __ge__ = __eq__
+
+    def __hash__(self):
+        return id(self)
+
+    def __getitem__(self, _):
+        return self
+
+    def __getattr__(self, _):
+        return self
+
+    def __call__(self, *_a, **_k):
+        return self
+
+    def __len__(self):
+        return 0
+
+    def __iter__(self):
+        return iter(())
+
+    def __contains__(self, _):
+        return False
+
+    def __float__(self):
+        return _NAN
+
+    def _same(self, *_):
+        return self
+
+    __add__ = __radd__ = __sub__ = __rsub__ = __mul__ = __rmul__ = _same
+    __truediv__ = __rtruediv__ = __floordiv__ = __rfloordiv__ = _same
+    __mod__ = __rmod__ = __neg__ = __pos__ = __abs__ = __round__ = _same
+
+
+def present(*xs):
+    """True when none of `xs` is an ABSENT stand-in."""
+    return not any(isinstance(x, Absent) for x in xs)
+
+
+def nth(seq, i=0, what=None):
+    """`seq[i]`, or an ABSENT saying how many items there were."""
+    n = 0 if seq is None else len(seq)
+    if -n <= i < n:
+        return seq[i]
+    return Absent(what or f"[{i}] of {n} item(s)")
+
+
+def first(it, what="no match"):
+    """`next(it)`, or ABSENT when it is exhausted."""
+    return next(iter(it), Absent(what))
+
+
+def field(mapping, key, what=None):
+    """`mapping[key]`, or ABSENT when the key (or the mapping) is missing."""
+    try:
+        return mapping[key]
+    except (KeyError, IndexError, TypeError):
+        return Absent(what or f"key {key!r}")
+
+
+def given(x, what="None"):
+    """`x`, or ABSENT when it is None - so `:.2f` and arithmetic cannot raise."""
+    return Absent(what) if x is None else x