Rounds 2, 3 and 4 each closed exactly the survivor they were handed and each time
the reviewer found the same shape one step over: the reduction, the call site, the
sibling argument, and now the sibling MODULE. Round 4's enumeration stopped at the
`Controller` class boundary; round 5's four blockers were reductions in validate.py,
over a list DERIVED from the roster three calls away from it. Closing four more sites
by hand would have produced a fifth rejection, so this round widens the instrument
instead and lets it enumerate.
⚠️ THE BLOCKERS ARE NOT EQUIVALENT MUTANTS - a safety refusal disappears, verified by
calling the shipped validator both ways on the real tree:
roster max_w 5000 (inverter-a) beside 2000 (inverter-b), sign_disagree_w 3000
clean -> 1 problem, "...max_w (inverter-b) is 2000 W, so the
SAFETY-02 sign-disagreement watchdog can never fire"
min(caps[:1]) +4 B -> 0 problems. The site STARTS.
caps_ix[:1] +4 B -> 0 problems.
the SAME roster with the small cap FIRST (2000, 5000)
clean -> 1 problem, naming inverter-a
min(caps[-1:]) +5 B -> 0 problems.
⚠️ AND THE ONE-ROSTER FIXTURE COULD NOT HAVE SEEN THAT. On [5000, 2000] the `[-1:]`
mutant still refuses, because last IS min there. A fixture of N members cannot separate
two reductions that agree on N members - which is why the behavioural half below is a
SET and not a roster.
THE INSTRUMENT (test_peakguard.py part 12j, widened past `Controller`)
Every `.py` under app/ is read off disk and parsed - NO MODULE IS NAMED IN THE CHECK -
and the roster is found by transitive closure from ONE seed, the `inverters` option key:
through returns, through lists ACCUMULATED in a loop over a roster (which is exactly
what `caps`, `roster` and `problems` are, and what round 4's rule could not express),
through attributes and properties, and THROUGH CALL ARGUMENTS, which is how it walks
into peakguard, arbiter, allocator, circulation, maintenance and store without being
told they exist. A slice of a roster stays a roster so a mutation cannot cut the taint;
an index is one unit and does not.
183 roster reductions across 9 modules, out of 23 files parsed:
main 96, allocator 24, validate 19, arbiter 14, circulation 10, maintenance 10,
peakguard 4, inverter 3, store 3. 14 modules reduce over no roster at all.
⚠️ THE HAND-WRITTEN MODULE LIST WOULD HAVE BEEN WRONG IN BOTH DIRECTIONS. It named
watchdog.py, which reduces over no roster at all (SAFETY-30's sign watchdogs are
strictly per-unit), and omitted maintenance.py and store.py, which both do. A vacuous
claim about one module and no claim at all about two others - which is the argument for
computing the scope, made with data.
The pin rediscovers ALL FOUR blockers without being told where to look, and finds a
FIFTH beside them (validate.py:783, rule 5's own message) that no review round named.
Its counterfactual runs at two depths: every enumerated site's expression mutated with
each of the four cuts this card has been defeated by (183 x 4 = 732 spellings, all
reported), and `[:1]` written into app/validate.py at each blocker position with the
WHOLE analysis re-run over the mutated source.
THE SWEEP, AND THE NUMBER THAT MUST NOT BE QUOTED ALONE
All 183 sites mutated to `[:1]`, +4 B each, against the full 19-file suite in
goodwe-addon-ci (:ro, -B, fresh rsync per mutant, 0 .pyc before and after - a read-only
mount cannot write one): 183/183 RED. ⚠️ That is TAUTOLOGICAL on its own, because the
pin makes every slice red. So the 51 whose first red was test_peakguard.py were re-run
with the pin NEUTRALISED:
145 of 183 a behavioural fixture separates the site from a slice of itself
38 of 183 ONLY the structural claim. Behaviourally UNGRADED.
All 38 are listed by site with what a `[:1]` there would cost, in the DECISIONS record
and in part 12j itself: 15 are rows and counts on the operator's page, 3 are
`len(targets)` arithmetic beside a write path that IS graded, 6 are allocator internals
ALLOC-01 reaches but not with enough units to separate. NONE of the 38 is closed
behaviourally by this card and none is counted as covered.
THE BEHAVIOURAL HALF, because a shape pin grades an identity and never a meaning
test_validate.py grows a ROSTER SET for the three rules that reduce over
`unit_caps_indexed()`: widths 2, 3, 4, 5 with the one small cap at EVERY position,
14 rosters x 3 rules = 42 runs of the real validator, each asserting the refusal fires
AND names the unit the number came off. Beside it a COMPUTED family table of twelve
candidates - max, first, last, the mean, [:1], [-1:], [:2], [:3], [1:], [:-1], [::2] -
each compared against what the shipped validator actually answered on the same roster.
Only `min` agrees everywhere; a member no roster kills is printed as a NAMED SURVIVOR.
⚠️ A THIRD RULE WAS READING THE FLAT `max_w`, AND IT IS SAFETY-30's
Found by reading the three branches side by side, NOT by the pin - and said that way
because it is the shape of what the pin cannot see. `unit_sign_disagree_w` was graded
against `_number(opts, "max_w", 2000.0)`, three lines under a branch that had already
stopped doing that. Both directions were measured before the fix:
two 2000 W units + a leftover `max_w: 5000` + unit_sign_disagree_w 3000 -> 0 problems.
The site started, the status page said `armed`, and the per-inverter watchdog could
not trip on EITHER unit. Identical sentence to the blocker, one branch over.
two 5000 W units with NO flat key -> REFUSED against a 2000 W default the operator
never wrote, for a threshold both units can reach.
It takes the same `weakest` the branch above takes and names the same unit. At a roster
of one `unit_caps()` is `[max_w]`, so the shipped single-inverter refusal is the same
comparison, the same boundary and the same sentence.
MUTATION PROOF (each: bytecode purged and counted 0 before and 0 after, the edit
re-read FROM DISK with the new text present and the old absent, byte delta printed)
B1 validate min(caps) -> min(caps[:1]) +4 B RED test_validate.py
B2 validate min(caps) -> min(caps[-1:]) +5 B RED test_validate.py
B3 validate caps_ix -> caps_ix[:1] +4 B RED test_validate.py
B4 validate rule 6 min -> min(caps_ix[-1:]) +5 B RED test_validate.py
B5 validate rule 5 msg -> min(caps_ix[:1]) +4 B RED test_validate.py
B6 validate rule 5b msg -> min(caps_ix[-1:]) +5 B RED test_validate.py
B7 CONTROL: weakest -> max(0.0, weakest) +10 B GREEN, as intended
R3a peakguard max(floors) -> min(floors) 0 B RED test_peakguard.py
R3b peakguard max(floors) -> max(floors[-2:]) +5 B RED test_peakguard.py
R3c main call site packs -> self.packs[:2] +4 B RED test_peakguard.py
R4a main pack_floor_soc -> vals[:2] +4 B RED test_peakguard.py
R4b main pack_floor_soc -> vals[-2:] +5 B RED test_peakguard.py
R4c main pack_floor_soc -> vals[:3] +4 B RED test_peakguard.py
R4d main cycle() any(...) -> self.inverters[:1] +4 B RED test_watchdog.py
B1-B6 are caught by the BEHAVIOURAL set in test_validate.py, before the pin is reached.
B7 is a deliberate no-op control: `max(0.0, weakest)` is `weakest` for weakest > 0, and
it stays green, so the battery is not merely red for everything.
R3a is a ZERO-byte delta, so the shipped function was called both ways as well:
packs floors [15.0, 30.0, 20.0], peak_soc_floor 15
binding_soc_floor(...) = 30.0 the 0-byte mutant would answer 15.0 (+15.0 pp)
-> the site would discharge to 15 % while pack-b's own BMS cuts out at 30 %.
⚠️ PRODUCTION IS DEGENERATE ON THE FLOOR AXIS. SPIKE-04: pack A and pack B BOTH floor
at 10 %, so a differing floor exists ONLY in the fixtures. That is the argument for
keeping them, not for simplifying them - collapsing them deletes the only data in this
repository that can see the reduction at all. Restated in config.yaml's example, in the
probe and in the fixtures.
⚠️ INVERTER B DOES NOT PHYSICALLY EXIST (~2026-09-12). Every second-unit figure here -
4600 W FROM ITS DATASHEET, 15 % illustrative, the whole roster SET - is SIMULATED and
labelled. Only inverter A's 10 % is read off hardware.
REBASED onto 67e649a. Two conflicts with SPIKE-04a, both in the blocks this card had
rewritten (config.yaml's roster example and the probe's C/D sections). Resolved to carry
BOTH claims, and the probe was RE-RUN rather than hand-merged: `all cases passed` on
ghcr.io/home-assistant/amd64-hassio-supervisor:2026.08.0, transcript updated with the
date. MUTATION.md habit 8 - a committed transcript stitched together out of two runs is
not a measurement.
Suite: 19/19 green in goodwe-addon-ci, mounted :ro, bytecode purged and verified 0
before and after. CI-06: test_peakguard.py run four times in isolation, green each time
(288 ok lines); test_validate.py three times, green each time.
MUTATION.md gains habits 12 and 13: build the instrument once the same shape has been
found twice AND make it discover its own scope, and say what the instrument cannot see
with sizes in the same breath.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU
GoodWe RS485 Controller — Home Assistant add-on repository
Replaces a GoodWe battery inverter's vendor controller with a local one: holds net grid exchange at zero by emulating the inverter's smart meter over RS485, and runs the monthly battery maintenance cycle the vendor box was doing.
repository.yaml add-on repository metadata
goodwe_controller/ the add-on
config.yaml manifest + options schema (the per-site config form)
app/ the controller
control.py the control law — pure functions, no I/O
maintenance.py the monthly cycle state machine
hass.py Supervisor/Core API access
store.py persistent state in /data
mqtt.py optional status entities
web.py ingress UI
main.py orchestration, heartbeat, failsafe behaviour
test_control.py runnable checks — no framework needed
test_maintenance.py runnable checks — walks a full cycle in fake time
DOCS.md the add-on's documentation tab
MUTATION.md how to run a mutation so the result means something
tools/mutation_run.sh the mutation harness - purges bytecode, then grades
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/build_guide.py its single source - rebuilds the HTML and PDF
FIELD-GUIDE.md how to edit and rebuild the guide
Picking this up after a break? Read HANDOVER.md first — current state,
what is known broken, and what to do next.
Install
Settings → Add-ons → Add-on store → ⋮ → Repositories → add
https://gittea.kammenstraatha.duckdns.org/admin/goodwe-addon
then install GoodWe RS485 Controller.
⚠️ 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
goodwe_controller/ into the machine's /addons/ folder, then
ha store reload — it appears as a Local add-on.
⚠️ Bump version: in goodwe_controller/config.yaml for every change.
Supervisor keys the built image by that version, so without a bump it silently
reuses the old image and your fix appears not to work — on your bench and on
every client's machine.
Requires Home Assistant OS or Supervised. Add-ons cannot be installed on HA Container or Core.
Read this first
The inverter holds its last command forever. It has no meter-timeout of its own — a controller that dies mid-command leaves the battery running until a human intervenes. Measured on real hardware: 5 kW of discharge held for 113 seconds after a controller went silent.
Three layers exist because of that, and only the third covers the Home Assistant machine itself dying:
- ESP32 watchdog — no fresh setpoint for ~30 s → command 0 W, and keep commanding it.
- Wind-down before firmware updates — 0 W written before the update starts.
- 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.
Development
The control law and the maintenance machine are pure Python with no Home Assistant imports, so they run anywhere:
cd goodwe_controller
python3 test_control.py
python3 test_maintenance.py
Both must pass before shipping any change. To prove a check bites - the way
almost every claim in this repository was established - mutate the module and
run tools/mutation_run.sh, which clears __pycache__ first. It is not
optional: a same-size edit reverted inside one second leaves CPython reusing the
old bytecode, and the run grades code that is not there. goodwe_controller/MUTATION.md
has the mechanism, the measurement, and what the flags do not do. They are not unit-test theatre —
each assertion corresponds to a rule whose absence produced an observed failure
on real hardware, and the comments in control.py say which.
Compatibility
Check the serial number, not the model name. Characters 6-8 of the serial are the platform tag:
| tag | platform | verdict |
|---|---|---|
ESU EMU ESA BPS BPU EMJ IJL |
105 — ES/EM/BP, AA55-era meter bus | supported |
SPB SPN |
745 — SBP G2 (GW…-SBP-20) |
no |
ESN ESC |
745 — ES G2 (GW…-ES-20) |
no |
ETU EHU BTU … |
205/745/753 — ET/EH/BT hybrids | no |
SDT DST MSU NSU … |
PV-only inverters — no battery to control | no |
A "-20" or "G2" suffix means a different platform with a different meter
protocol. The tags come from the goodwe library's PLATFORM_105_MODELS, which
is also what Home Assistant's own integration uses to pick a protocol.
- GoodWe ES / BP family inverters (AA55 / RS485 meter-bus generation)
- The protocol is reverse-engineered. There is no vendor contract, and a firmware change on GoodWe's side could break every installation at once. Say so when you sell it.