Merge pull request 'SAFETY-52: a battery that refuses is asked for 0 W, with a 200 W probe every 15 min' (#141) from SAFETY-52-refused-hold into release/1.0

goodwe_controller/DECISIONS/SAFETY-52-a-battery-that-refuses.md

@@ -0,0 +1,110 @@
+# SAFETY-52 - a battery that refuses is asked for 0 W
+
+**Decided 2026-09-27 by the owner, on the phase A plan (option D3). All four
+questions answered yes.**
+
+## The defect
+
+At the BMS cut-out the battery gives ~0 W whatever it is asked. The saturation
+freeze (`control.py`, `frozen`) then holds the request where it stood, and its
+SAFETY-13 exit cannot fire, because a reading of ~0 against a large ask lies
+inside the interval a limit can produce. The request stood at +5000 W for
+11.87 h on 2026-09-06 and at +1940 W for 3 h 55 m on the bus on 2026-09-19. It
+moved again only when the grid error changed sign. SAFETY-48's lead cap only
+changes where `i_w` parks (one slew step ahead instead of at the rail). When
+the request moved after the reading went flat, the stale-reading gate won
+instead and ran SAFETY-59's ~70 s trip cycle.
+
+## What was decided
+
+1. **A refused direction is held at 0 W**, reason `battery refuses`. It engages
+   in `compute()` when the freeze has held `SETTLE_CYCLES` and the reading is
+   below `REFUSED_BELOW_W` (100 W, the probe's own answer) against an ask beyond
+   `saturation_w`. The drop to 0 skips
+   the slew limit (it only removes an ask nobody meets). The direction is
+   carried like `sat_count` (`refused=`, `Decision.refused`).
+2. **A 200 W probe every 15 minutes, 34 s long** (`PROBE_W`, `PROBE_EVERY_S`,
+   `PROBE_S`; twice `BATT_OBLIGED_S`). A reading of at least 100 W in the held
+   direction ends the refusal, during a probe or not. 200 W is below `freshness.MOVE_W` (250 W), so a probe cannot arm
+   the gate. The clock is main.py's `now_mono`; `compute()` stays clockless.
+3. **A gate trip while the loop is frozen on a ~0 W reading is a refusal** for
+   control (`Controller._refusal_from_stale`). This is what stops the ~70 s
+   cycle. The log keeps SAFETY-56's two-explanation wording.
+4. **No SoC in the loop.** SAFETY-25 Option A stands. Nothing reads SoC.
+
+Other exits: the loop wants the other direction (charge is accepted at the
+floor), control stopped or started, another writer on the wire (the arbiter
+reseed). A gap in the readings keeps the refusal, because the gate's own stop is
+what seeds it.
+
+**One inverter only.** At N>1, OPT-09's `pack` limit already closes an empty
+battery's discharge end and moves its share. There, a one-unit gate trip must
+not refuse the site. `compute()` is passed `refused=None` there, and that path
+is release/1.0's law unchanged (the `i_w=None` equivalence sweep in
+`test_control.py` still holds).
+
+## Evidence
+
+`test_refusal.py` drives the real Controller and gate (the 09-06 and 09-19
+shapes, recovery with no sign change, the probe cadence, every exit).
+`tools/replay_refusal.py` replays the 16-day capture, same model as
+`replay_recorded_loop.py`, and should be read for deltas:
+
+| plant | law | gate trips | request >1 kW above delivery | longest held | import / export kWh | worst 15-min |
+|---|---|---|---|---|---|---|
+| fitted | old | 85 | 113.3 h | 16.57 h | 112.0 / 35.2 | 3434 W |
+| fitted | new | 130 (133 after review) | 11.4 h | 0.21 h | 112.3 / 35.4 | 3456 W |
+| offset 0 W | old | 1010 | 102.2 h | 16.58 h | 112.0 / 35.2 | 3434 W |
+| offset 0 W | new | 85 | 6.1 h | 0.33 h | 111.9 / 35.1 | 3434 W |
+
+**Traced in review (#141).** The +22 W worst quarter is the old law's worst
+quarter too. There the old law stands at +2060 W on a pack giving 0 W, and the
+new law asks 0 W, which the fitted plant answers with its -22 W offset: 22 W
+charged from the grid. The fit above the floor reads `batt = cmd - 28 W`, so a
+real inverter asked 0 W may do the same. Of the 71 new-law trips with no
+old-law trip within 2 min, 59 come 85-97 s after an answered probe. The offset has lifted the modelled pack
+just above its floor, the probe is answered, control ramps, the pack empties
+again mid-ramp, and the gate trips, which re-seeds the hold. The other 12
+follow an other-direction exit the same way. On a site this is one
+`STALE_READING` ERROR line per answered probe at most, and only on a battery
+that answers a probe and then cuts out again. Catching the re-cut before the
+gate needs a faster engage than `SETTLE_CYCLES`, which accuses a healthy slow
+battery, so it is left to SAFETY-58/59. After the review changes below the
+fitted-plant row reads 133 trips (the delivery exit now also catches answers
+that arrive after the probe window); the other figures are unchanged. Rejected alternatives and their figures are in
+the phase A plan: bounding the integrator by demand made the worst quarter
++541 W worse or cycled the gate 3368 times, and an SoC envelope needs the
+configured floor to be right and needs SoC.
+
+## Review changes (#141)
+
+- **"Gives nothing" is below 100 W, not below 500 W.** At `saturation_w` a
+  battery derated to 100-499 W (cold, a tapering battery) was held at 0 W for
+  ~93 % of the time: 300 W derated gave 86 Wh in 4 h against 1 200 Wh on the
+  old law. The capture has 0.11 h in that band, so the replay does not move.
+- **Any delivery ends the hold, not only an answered probe.** With
+  `meter_poll_s: 1` the 12 cycles last 12 s, less than a healthy battery's
+  reading lag (up to `BATT_OBLIGED_S`, 17 s). That engaged on a healthy step and
+  held it for 15 min. Now the late reading ends it within seconds (2 s held in
+  `test_refusal.py` part 5b).
+- **N>1 is stated as a limit in DOCS.** The pack limit there covers an empty
+  battery only when its cut-out level is configured right.
+
+## Not covered
+
+A battery that gives a steady part of the ask (e.g. a 500 W keep-alive) is a
+genuine limit (SAFETY-13 case a) and still holds its request.
+
+## What SAFETY-58 and SAFETY-59 must take into account
+
+- **SAFETY-58** (the first read after a rest trips at once): a probe never arms
+  the gate (200 < 250 W), but the refusal seeding reads the trip. If 58 delays
+  the first verdict, the seed arrives later. The 09-19 shape then needs the
+  compute-side engagement (12 cycles) to win, which it does only while the
+  request stands still. Keep `test_refusal.py` part 4 green.
+- **SAFETY-59** (DOCS says a ~70 s pattern proves a failed register): with this
+  change a refusing battery no longer produces the pattern at one inverter. The
+  DOCS text should say so, and that the `battery refuses` reason is the
+  discriminator the add-on now has. At N>1 the old pattern can still occur.
+- If either changes `MOVE_W`, `PROBE_W` must stay below it.
+  `test_refusal.py` part 2 checks the inequality.

goodwe_controller/DOCS.md

@@ -526,7 +526,7 @@ accumulator is doing:
 | `Loop integrator lead` | W | that value minus **the command it was computed against**, i.e. the command the previous cycle left standing |
 | `Loop reason` | — | the law's own word for this cycle |
 
-`Loop reason` takes one of eight values:
+`Loop reason` takes one of ten values:
 
 | value | what happened |
 |---|---|
@@ -538,6 +538,27 @@ accumulator is doing:
 | `saturated-freeze` | the inverter is not following, so the command's magnitude may fall but not rise |
 | `freeze-released` | the freeze had run out of plant-shaped explanations and the command was let move again |
 | `not-running` | control is stopped **and** shadow mode is off, so the loop did not run |
+| `battery refuses` | the battery gave less than 100 W for 12 cycles (a minute at a 5-second meter) while asked for more than 500 W, so the add-on asks 0 W in that direction (see below) |
+| `battery probe` | the add-on asks 200 W to test whether a refusing battery gives power again |
+
+**When the battery refuses.** At its cut-out level the battery gives nothing,
+whatever it is asked. The add-on then asks 0 W instead of repeating its last
+request, and the `Why` row reads *The battery refuses to give power: 0 W*. Every
+15 minutes it asks 200 W for about half a minute. Control resumes as soon as
+the battery gives 100 W or more, when the grid needs charging instead, and when
+control is stopped or started. 200 W is below the 250 W the stale-reading check
+needs, so a test never trips it. A battery that gives some power, even 100 W,
+is not refusing and keeps its request.
+
+⚠️ **One inverter only.** With several inverters this hold is off. There, the
+battery level limit moves an empty battery's share to the others, but only if
+its “Battery cut-out level” matches where the battery really stops. A battery
+that refuses at another level, or for another reason (cold, a battery fault),
+can still hold its last request until the grid starts to export.
+
+*For installers:* SAFETY-52. The event log reads `BATTERY REFUSES …` and
+`BATTERY REFUSES ENDED: …`, and the INFO line ends in `BATTERY_REFUSES`.
+`DECISIONS/SAFETY-52-a-battery-that-refuses.md` has the replay figures.
 
 ⚠️ **`Loop reason` is not the `Why` row on the status page, and the two will
 often disagree.** `Why` is the *arbiter's* answer in words — *Keeping the grid

goodwe_controller/app/control.py

@@ -265,6 +265,34 @@ _SAT_COUNT_CAP = SETTLE_CYCLES + 1                           # 13
 # `slew_limit_w()` and therefore with the rail.
 SLEW_LEAD_STEPS = 1
 
+# ---------------------------------------------------------------------------
+# SAFETY-52. A BATTERY THAT REFUSES IS ASKED FOR 0 W, NOT HELD AT ITS LAST ASK.
+#
+# At the BMS cut-out the pack delivers ~0 W whatever it is asked, so the
+# saturation freeze below holds the command where it stood (the recorded
+# 09-06 case: +5000 W for 11.87 h) until the grid error changes sign. The
+# freeze's own exit cannot help: a reading of ~0 against a large ask is inside
+# the interval a limit can produce. So a refused DIRECTION is held at 0 W,
+# carried between cycles like `sat_count`, and left again when the loop wants
+# the other direction, when a small probe is answered, or when the caller
+# resets it (stop, start, another writer). The record is DECISIONS/SAFETY-52.
+#
+# PROBE_W is below freshness.MOVE_W (250 W) on purpose: a probe that small can
+# never arm the stale-reading gate, so it cannot start the gate's ~70 s cycle.
+# test_refusal.py pins the inequality. The cadence and length are the owner's
+# 2026-09-27 answer (every 15 minutes) and freshness.BATT_OBLIGED_S twice over
+# (17 s is how long a healthy reading needs to show a command).
+REFUSED = "battery refuses"
+PROBING = "battery probe"
+PROBE_W = 200.0
+PROBE_ANSWER_W = PROBE_W / 2
+# "Gives nothing" is below the probe's own answer, not below `saturation_w`: a
+# pack derated to 100-499 W is a limit, and at 500 W it kept ~7 % of its power
+# (review of #141). The capture's refusals read -4 W.
+REFUSED_BELOW_W = PROBE_ANSWER_W
+PROBE_EVERY_S = 900.0
+PROBE_S = 34.0
+
 
 @dataclass(frozen=True)
 class Tuning:
@@ -346,6 +374,9 @@ class Decision:
     i_bound_w: float = 0.0
     requested_w: float = 0.0
     clamped_w: float = 0.0
+    # SAFETY-52. The refused direction to carry back in (+1 discharge, -1
+    # charge, 0 none), or None when the caller does not carry it.
+    refused: int | None = None
 
 
 def slew_limit_w(tuning: Tuning) -> float:
@@ -442,6 +473,8 @@ def compute(
     tuning: Tuning,
     sat_count: int = 0,
     i_w: float | None = None,
+    refused: int | None = None,
+    probe: bool = False,
 ) -> Decision:
     """One control cycle. A cycle is one meter update (~5 s on a HomeWizard P1).
 
@@ -449,6 +482,9 @@ def compute(
     `grid_w`   net grid power, + = importing
     `actual_w` what the inverter reports it is doing, + = discharging
     `i_w`      the carried integrator, or None to seed it from `prev_w`
+    `refused`  SAFETY-52's carried refused direction, or None to leave it out
+               (the `i_w=None` equivalence path does)
+    `probe`    the caller's clock says a refused direction may try PROBE_W now
     """
     reason = "tracking"
 
@@ -739,6 +775,27 @@ def compute(
             target = min(target, prev_w) if prev_w > 0 else max(target, prev_w)
             reason = "saturated-freeze"
 
+    # --- SAFETY-52: a refused direction is held at 0 W ----------------------
+    # Engages only where the freeze has held for SETTLE_CYCLES and the unit
+    # delivers ~nothing: a reading below REFUSED_BELOW_W against an ask beyond
+    # `saturation_w` is a refusal, not a slow plant. The drop to 0 skips the slew
+    # limit because it only removes an ask the battery is not meeting.
+    if refused is not None:
+        if (refused == 0 and frozen and sat_count >= SETTLE_CYCLES
+                and abs(prev_w) > tuning.saturation_w
+                and abs(actual_w) < REFUSED_BELOW_W):
+            refused = 1 if prev_w > 0 else -1
+        if refused and refused * i_w < 0:
+            refused = 0                          # the loop wants the other way
+        elif refused and refused * actual_w >= PROBE_ANSWER_W:
+            refused = 0                          # it delivers: a probe answered,
+            #                                     or a slow reading arriving
+        elif refused:
+            wants = refused * i_w > 0
+            i_w = 0.0
+            target = refused * PROBE_W if probe and wants else 0.0
+            reason = PROBING if probe and wants else REFUSED
+
     # --- quantise ----------------------------------------------------------
     # 10 W. The register is 1 W and the inverter reports at 1 W, but its
     # response lands on a coarser ladder (~17.6 W measured at ~900 W, consistent
@@ -749,7 +806,7 @@ def compute(
 
     return Decision(float(target), sat_count, frozen, reason, float(i_w),
                     i_clamped, clamped, float(i_bound_w), float(want),
-                    float(clamped_w))
+                    float(clamped_w), refused)
 
 
 def maintenance_charge_floor(

goodwe_controller/app/main.py

@@ -39,6 +39,7 @@ from .arbiter import (
     P_LOOP, P_MAINT_SHAPE, P_MAINTENANCE, P_PEAK, P_SAFETY,
     Claim, Resolution, actuator_for, resolve,
 )
+from . import control as _ctl
 from .control import Tuning, compute, maintenance_charge_floor, peak_at_risk
 from .delivery import (
     DELIVERY_OPTION_DEFAULTS, DeliveryConfig, UnitDelivery,
@@ -241,6 +242,10 @@ def why_key(winner: str, claims) -> str:
     disagreement"). A failsafe with no claim of its own is the arbiter's "no
     claim was made", or main.py's refusal to split the power ("unsplit").
     """
+    if winner == "loop":
+        # SAFETY-52: a loop holding a refused direction says so.
+        return next((c.reason for c in claims if c.source == "loop"
+                     and c.reason in (_ctl.REFUSED, _ctl.PROBING)), winner)
     if winner in ("safety", "failsafe"):
         return next((c.reason for c in claims
                      if c.source == winner and c.kind == "set"),
@@ -925,6 +930,12 @@ class Controller:
         self.target = 0.0
         self.sat_count = 0
         self.i_w = 0.0        # the loop's integrator, carried between cycles
+        # SAFETY-52. The direction the battery refuses (+1 / -1 / 0), carried
+        # like `i_w`, and when the refusal (or its last probe) started.
+        self.batt_refused = 0
+        self.batt_refused_at = None
+        self._now_mono = None
+        self._refusal_auto = False
         # TEL-10. What the last cycle's loop did, kept for publication. Seeded
         # to the SAME values the "stopped or blind" branch of `cycle()` writes,
         # because before the first cycle the loop has not run - which is the
@@ -1058,6 +1069,69 @@ class Controller:
         self.loop_pass_mono = None
 
     # -- helpers -------------------------------------------------------------
+    # --- SAFETY-52: a battery that refuses is asked for 0 W ------------------
+    def _refusal_probe(self) -> bool:
+        """True while a refused direction may try `PROBE_W` (every 15 min)."""
+        if (not self.batt_refused or self.batt_refused_at is None
+                or self._now_mono is None):
+            return False
+        held = self._now_mono - self.batt_refused_at
+        if held >= _ctl.PROBE_EVERY_S + _ctl.PROBE_S:
+            self.batt_refused_at = self._now_mono
+            return False
+        return held >= _ctl.PROBE_EVERY_S
+
+    def _refusal_start(self, sign: int, evidence: str) -> None:
+        self.batt_refused = sign
+        self.batt_refused_at = self._now_mono
+        self.log_event(f"BATTERY REFUSES {evidence}",
+                       hint=messages.hint("battery_refuses"))
+        _LOG.info("The battery refuses to give power, so the add-on asks 0 W "
+                  "and tries %.0f W every %.0f minutes: BATTERY_REFUSES.",
+                  _ctl.PROBE_W, _ctl.PROBE_EVERY_S / 60)
+        _LOG.debug("Evidence: BATTERY_REFUSES: %s.", evidence)
+
+    def _refusal_end(self, why: str) -> None:
+        if not self.batt_refused:
+            return
+        self.batt_refused, self.batt_refused_at = 0, None
+        self.log_event(f"BATTERY REFUSES ENDED: {why}",
+                       hint=messages.hint("battery_gives"))
+        _LOG.info("The battery refusal ends, control asks for power again: %s.",
+                  why)
+
+    def _refusal_update(self, decision, asked_w, batt_w, probe) -> None:
+        """Follow `compute()`'s carried refused direction, and say so."""
+        now = decision.refused or 0
+        if now and not self.batt_refused:
+            self._refusal_start(now, f"asked {asked_w:+.0f} W, the battery "
+                                     f"gave {batt_w:+.0f} W for "
+                                     f"{decision.sat_count} cycles")
+        elif self.batt_refused and not now:
+            gave = self.batt_refused * batt_w >= _ctl.PROBE_ANSWER_W
+            self._refusal_end("the probe was answered" if gave and probe
+                              else "the battery gives power" if gave
+                              else "the grid now asks the other direction")
+
+    def _refusal_from_stale(self, inv, now_mono) -> None:
+        """A stale-reading stop while the loop is frozen on ~0 W is a refusal.
+
+        Only at one inverter: with several, one empty battery must not stop the
+        site (OPT-09's pack limit moves its share to the others).
+        """
+        t = self.tuning
+        standing = inv.standing_w()
+        if (len(self.inverters) == 1 and (self.auto or self.shadow)
+                and not self.batt_refused
+                and self.sat_count >= t.saturation_cycles
+                and inv.batt_fresh.held is not None
+                and abs(inv.batt_fresh.held) < _ctl.REFUSED_BELOW_W
+                and abs(standing) > t.saturation_w):
+            self._now_mono = now_mono
+            self._refusal_start(1 if standing > 0 else -1,
+                                f"stale reading {inv.batt_fresh.held:+.0f} W "
+                                f"while asked {standing:+.0f} W")
+
     def log_event(self, msg: str, hint: str | None = None) -> None:
         """`msg` goes on the action log, the add-on's own technical record.
         `hint` is `messages.hint()`'s plain words for the same event, and is
@@ -1840,6 +1914,7 @@ class Controller:
         """
         o = self.o
         now_mono = freshness.monotonic() if now_mono is None else float(now_mono)
+        self._now_mono = now_mono
         if self.p1_enabled:
             # ⚠️ P1 is the only authoritative measurement of what the utility
             # sees (§5.1). When it is stale this is None, which falls into the
@@ -2003,6 +2078,7 @@ class Controller:
         if inv.batt_fresh.stale and not was_stale:
             self.log_event(f"STALE {inv.name}: " + inv.batt_fresh.reason,
                            hint=messages.hint("battery_stuck", unit=inv.name))
+            self._refusal_from_stale(inv, now_mono)
             # ⚠️ SAFETY-57 REWROTE THE LAST SENTENCE OF THIS LINE AND NOTHING
             # ELSE IN IT. The escape clause used to read "It clears itself the
             # moment the register reports a different value", full stop - and
@@ -3340,6 +3416,12 @@ class Controller:
         # loop should be. It is safe because the loop's `prev_w` is
         # `self.target`, which the end of this method re-seeds to what is
         # actually standing on the wire.
+        # SAFETY-52: a refusal learned while control ran does not survive a
+        # stop or a start (shadow mode keeps the loop running when stopped).
+        if bool(self.auto) != self._refusal_auto:
+            self._refusal_auto = bool(self.auto)
+            self._refusal_end("control started" if self.auto
+                              else "control stopped")
         if (self.auto or self.shadow) and self.inputs_ok:
             # ⚠️ prev is the ARBITER's last output, not the loop's own last
             # wish. If something outranked the loop, that is what the hardware
@@ -3357,6 +3439,13 @@ class Controller:
             # stale period as power.
             if self.loop_w is None or self.target != self.loop_w:
                 self.i_w = self.target
+            # SAFETY-52: another writer overrode the loop, so a refusal learned
+            # against the loop's own ask no longer describes the wire. A gap
+            # (`loop_w` None: blind or stopped) keeps it: the stale-reading stop
+            # is what seeds it, and dropping it there restarts the ~70 s cycle.
+            if self.loop_w is not None and self.target != self.loop_w:
+                self._refusal_end("another writer")
+            probe = self._refusal_probe()
             # ⚠️ `actual_w` IS THE SITE SUM AND THAT IS DEV-02's OTHER HALF.
             # The anti-windup test inside compute() is
             # `abs(prev_w - actual_w) > saturation_w`, and `prev_w` is the SITE
@@ -3385,6 +3474,10 @@ class Controller:
                 tuning=self.tuning,
                 sat_count=self.sat_count,
                 i_w=self.i_w,
+                # SAFETY-52 at one inverter only: with several, OPT-09's pack
+                # limit already closes an empty battery's discharge end.
+                refused=self.batt_refused if len(self.inverters) == 1 else None,
+                probe=probe,
             )
             if decision.frozen and self.sat_count < self.tuning.saturation_cycles:
                 self.log_event(f"saturation freeze ({self.target:.0f} W vs "
@@ -3393,6 +3486,7 @@ class Controller:
             self.sat_count = decision.sat_count
             self.i_w = decision.i_w
             self.loop_w = decision.target_w
+            self._refusal_update(decision, loop_prev, site_batt, probe)
             # --- TEL-10 ------------------------------------------------------
             # ⚠️ THE INTEGRATOR HAS NEVER LEFT THIS PROCESS, AND THAT IS WHAT
             # THE CARD IS. `self.i_w` is carried between cycles and published

goodwe_controller/app/messages.py

@@ -802,6 +802,9 @@ WHY_WINNER = {
     # failsafe winner. test_messages.py part 7 finds every one in the code.
     "sign disagreement": "Safety stop, power went the wrong way",
     "unsplit": "The power could not be split, all at 0 W",
+    # SAFETY-52: the loop's two words for a battery that gives nothing.
+    "battery refuses": "The battery refuses to give power",
+    "battery probe": "Testing if the battery gives power again",
 }
 WHY_LIMIT = {
     "peak(quarter peak)": "the peak limit",
@@ -852,6 +855,8 @@ HINTS = {
     "stop_restored": "{unit}: an earlier safety stop is back, it stays at 0 W",
     "battery_stuck": "{unit}: battery power reading stopped changing",
     "battery_back": "{unit}: battery power reading is used again",
+    "battery_refuses": "The battery refuses to give power, the add-on asks 0 W",
+    "battery_gives": "The battery refusal ended, control asks for power again",
     "bad_value": "The add-on made an invalid power value, inverters set to 0 W",
     "write_blocked": "{unit}: a power request was blocked, it is set to 0 W",
     "all_blocked": "A power request was blocked, inverters set to 0 W",

goodwe_controller/test_clamp.py

@@ -497,8 +497,13 @@ check(f"AC 1: NOT ONE of the {len(emitted)} values that reached the device "
 # largest emitted value is what it is and not 5000 W. The clamp is what makes it
 # bounded; the freeze is what makes it small. A check that read
 # `max(emitted) == max_w` would have been asserting the freeze, not the clamp.
+# SAFETY-52 re-baseline: an inverter reporting 0 W for SETTLE_CYCLES is a
+# battery that refuses, so the command then drops to 0 W. The freeze still
+# engaged first, and the event log says so.
 check(f"...and the saturation freeze is what pins it at {max(emitted):,.0f} W "
-      f"rather than the rail", ctl_r.sat_count >= ctl_r.tuning.saturation_cycles)
+      f"rather than the rail",
+      any("saturation freeze" in e for e in ctl_r.events)
+      and max(emitted) < LIVE_MAX_W)
 
 notes_r = clamp_notes(hass_r)
 print(f"    the loop clamped on {ctl_r.clamp_wd.engagements} of {60} cycles, "
@@ -580,8 +585,12 @@ check("UX-07 item 1: during a bound episode an earlier over-rating count is "
 
 # ⚠️ NOT A TRIP. 11.2's action is "clamp and alarm"; the loop keeps running and
 # keeps writing the clamped value. If a later cut changes that it must come here.
-check(f"it is NOT a trip - the command stands at {ctl_r.target:+.0f} W, not 0 W",
-      ctl_r.target != 0.0 and ctl_r.target == hass_r.writes[-1])
+# SAFETY-52: the loop itself now asks 0 W of an inverter that gives nothing,
+# with its own reason. That is the loop's decision, not a stop.
+check(f"it is NOT a trip - the command stands at {ctl_r.target:+.0f} W because "
+      f"the loop says '{ctl_r.loop_reason}', not because of a stop",
+      ctl_r.loop_reason == "battery refuses"
+      and ctl_r.target == hass_r.writes[-1])
 check("...and the controller still reports itself running, not failsafe",
       ctl_r.auto and not ctl_r.sign_wd.tripped)
 

goodwe_controller/test_delivery.py

@@ -1147,8 +1147,10 @@ async def _one():
             "soc_entity": "sensor.soc", "batt_entity": "sensor.batt",
             "meter_source": "off", "max_w": 2000, "gain": 0.6,
             # ⚠️ THE SAME 1 s AS THE TWO-INVERTER FIXTURE, AND THAT IS WHAT
-            # MAKES THIS SECTION NON-VACUOUS. The run below is 2 s of wall clock
-            # against a 1 s window, so a hold is not what stops this firing -
+            # MAKES THIS SECTION NON-VACUOUS. The run below is 1.1 s of wall
+            # clock against a 1 s window (SAFETY-52 shortened it from 2 s, and
+            # "the window was never even opened" below is what still makes it
+            # non-vacuous), so a hold is not what stops this firing -
             # the reduction is. With a shipped-length hold "nothing was
             # reported" would be true of a fixture that simply ran out of time.
             "bms_soc_floor": _FLOOR_PCT, "delivery_hold_s": 1,
@@ -1158,7 +1160,10 @@ async def _one():
     c.inverters[0].dev_min, c.inverters[0].dev_max = -2000.0, 2000.0
     c.auto = True
     hass.ctrl = c
-    await _drive(c, n=20, dt=0.1)
+    # SAFETY-52: from SETTLE_CYCLES of delivering nothing the loop asks 0 W
+    # (the battery refuses), so the run stops just before that. 11 cycles is
+    # still 1.1 s against the 1 s hold.
+    await _drive(c, n=11, dt=0.1)
     return c, hass, store
 
 

goodwe_controller/test_messages.py

@@ -1399,6 +1399,7 @@ import logging                                                    # noqa: E402
 from app import hass as _hass, p1 as _p1, validate as _validate, web as _web  # noqa: E402
 from app.arbiter import Claim                                     # noqa: E402
 from app.main import Controller, why_key                          # noqa: E402
+from app import control as _control                              # noqa: E402
 from app import main as _main                                    # noqa: E402
 
 
@@ -1585,6 +1586,11 @@ for _f in sorted(APP.glob("*.py")):
 _keys = {why_key(s, [Claim.set(s, 0, 0.0, r)]) for s, r in _SOURCES}
 _keys |= {why_key("failsafe", []),
           why_key("failsafe", [Claim.set("loop", 0, 1.0, "tracking")])}
+# SAFETY-52: the loop's claim reason is computed, so the scan cannot see it.
+_keys |= {why_key("loop", [Claim.set("loop", 0, 0.0, _r)])
+          for _r in (_control.REFUSED, _control.PROBING)}
+check("...including the loop's two battery-refuses reasons, which get words of "
+      "their own", {_control.REFUSED, _control.PROBING} <= _keys)
 check(f"the scan found the claims ({len(_SOURCES)}), including the latched "
       f"per-inverter stop the 2d test saw as 'Other'",
       ("failsafe", "sign disagreement") in _SOURCES and len(_SOURCES) >= 8)

goodwe_controller/test_price.py

@@ -4412,12 +4412,16 @@ check(f"AC, AND THE WHOLE OF DEFECT 4: 'trading is off' and 'trading is on "
       f"`off (arbitrage_enabled)` for both - naming an option that is `true` "
       f"in the options blob",
       _T11_OFF[0]["Arbitrage"] != _T11_ON_HELD[0]["Arbitrage"])
+# ⚠️ THE "Why" ROW OF THE SAME RENDER, NOT A SECOND READ OF `why_words`. Since
+# UX-10 the waiting sentence counts its seconds when it is read, so reading the
+# property again here, after the other renders above, could cross a second
+# ("1 second" in the row, "2 seconds" now) - CI run 953 on PR #141 did.
 check(f"...and the armed-but-held row carries the CONTROL LOOP'S OWN REASON "
-      f"({_T11_ON_HELD[1].why_words!r}), so the operator is told which input is "
+      f"({_T11_ON_HELD[0]['Why']!r}), so the operator is told which input is "
       f"missing rather than being sent to look at a switch that is already on. "
       f"The reason comes from main.py, not from this file",
-      _T11_ON_HELD[1].why_words
-      and _T11_ON_HELD[1].why_words in _T11_ON_HELD[0]["Arbitrage"])
+      _T11_ON_HELD[0]["Why"].startswith("A reading is missing")
+      and _T11_ON_HELD[0]["Why"] in _T11_ON_HELD[0]["Arbitrage"])
 check(f"...and a cycle that DID reach the step renders the strategy's own "
       f"sentence - {_T11_ON_OK[1].arb.explain()[:50]!r} - rather than a "
       f"re-derivation of it, which is the guarantee OPT-04 put on this row and "

goodwe_controller/test_refusal.py

@@ -0,0 +1,475 @@
+"""Runnable check for SAFETY-52.  `python3 test_refusal.py`
+
+A battery that refuses to give power (the BMS cut-out) used to leave the
+command standing at its last ask for hours: +5000 W for 11.87 h on 2026-09-06,
++1940 W for 3 h 55 m on the bus on 2026-09-19. Now a refused direction is held
+at 0 W, a 200 W probe asks every 15 minutes, and the refusal ends on charge, on
+an answered probe, on stop/start and when another writer takes the wire.
+DECISIONS/SAFETY-52 has the record and the replay figures.
+
+Mutating the modules this file grades? Purge `__pycache__` first, or run
+`tools/mutation_run.sh`, which does - see MUTATION.md.
+
+Parts 1-5 drive the REAL `Controller` (read_inputs + cycle, the real
+SAFETY-37/57 gate) against a scripted battery whose reading stands at exactly
+-4 W for any request >= -4 W at the cut-out, and follows otherwise. Time is the
+`now_mono` handed to `read_inputs()`, so 12 hours run in seconds. `OLD` runs the
+same fixture with `refused=None` forced into `compute()` - release/1.0's law -
+so every "new" figure is shown beside the one it replaces. Part 4 also runs
+`compute()` alone, as the bus saw 09-19 before the gate existed.
+
+Mutations, each on a copy of this tree purged of `__pycache__`, graded with
+`python3 -B` over test_refusal, test_control, test_clamp, test_telemetry and
+test_messages (MUTATION.md). Reds are failing checks, on this tree:
+
+  #   mutation                                                 reds
+  --  -------------------------------------------------------  ---------------
+  R1  control.py: the engage `if` -> `if False and ...`          8 here + 1 clamp
+      (release/1.0's behaviour)
+  R2  control.py: the exit on the other direction removed        1
+  R3  control.py: the exit on an answered probe removed          2
+  R4  control.py: `PROBE_W = 300.0`, above the gate's 250 W       4
+  R5  control.py: the hold keeps the old target, not 0 W          4
+  R6  main.py: `_refusal_from_stale()` returns at once           1
+  R7  main.py: another writer no longer ends the refusal         1
+  R8  main.py: stop/start no longer ends the refusal             1
+  R9  main.py: the probe window never opens                      4
+  R10 main.py: seed from a stale stop below `saturation_w` again,  1
+      not below REFUSED_BELOW_W (review of #141). The same mutation
+      in control.py's engage clause SURVIVES, and that is expected:
+      the delivery exit (R11) ends such a refusal in the same cycle.
+  R11 control.py: only an answered PROBE ends the refusal          2
+      (`and probe` back in the delivery exit; review of #141)
+"""
+
+import asyncio
+import sys
+from datetime import datetime, timedelta, timezone
+
+from app import control, freshness
+from app.control import PROBE_EVERY_S, PROBE_S, PROBE_W, REFUSED, PROBING
+from app.main import Controller, why_key
+from app.arbiter import Claim
+from app import messages
+
+fails = []
+
+
+def check(name, cond):
+    print(f"  {'ok  ' if cond else 'FAIL'} {name}")
+    if not cond:
+        fails.append(name)
+
+
+LIVE = {"max_w": 5000.0, "gain": 0.6, "slew_w": 400.0, "target_grid_w": -10.0,
+        "deadband_w": 15, "step_w": 10}
+TICK = 5.0            # the meter's measured median tick (replay_recorded_loop)
+CUT_W = -4.0          # what the register reads at the cut-out, 2026-09-06
+H = 3600.0
+BASE = datetime(2026, 9, 6, 19, 30, tzinfo=timezone.utc)
+
+
+class _Store:
+    def __init__(self):
+        self.data = {}
+
+    def set(self, *a):
+        pass
+
+    def get_time(self, *a):
+        return None
+
+
+class _Pub:
+    enabled = False
+
+    def publish(self, values):
+        pass
+
+    def close(self):
+        pass
+
+
+class _Hass:
+    """House load, and a battery that follows unless `cut(t)` says it refuses.
+
+    At the cut-out the reading is exactly CUT_W for any request >= CUT_W (a flat
+    register, which is what arms or does not arm the stale-reading gate). A
+    charge request is followed: the pack accepts charge at the floor.
+    `cap(t)` limits discharge while not cut (the 09-06 pack gave 4570 W at 10 %).
+    """
+
+    def __init__(self, load, cut, cap=lambda t: 1e9):
+        self.load, self.cut, self.cap = load, cut, cap
+        self.t = 0.0
+        self.cmd = 0.0
+        self.writes = []
+
+    def batt(self):
+        if self.cut(self.t) and self.cmd >= CUT_W:
+            return CUT_W
+        return float(round(min(self.cmd, self.cap(self.t))))
+
+    async def limits(self, entity):
+        return (-LIVE["max_w"], LIVE["max_w"], 1.0)
+
+    async def number(self, entity, invert=False):
+        b = self.batt()
+        return {"sensor.grid": self.load(self.t) - b, "sensor.soc": 9.0,
+                "sensor.batt": b}.get(entity)
+
+    async def set_number(self, entity, value):
+        self.writes.append((self.t, float(value)))
+        self.cmd = float(value)
+        return True
+
+    async def call(self, *a):
+        return True
+
+
+def run(load, cut, dur, cap=lambda t: 1e9, old=False, events=None):
+    """Real cycles every TICK seconds of `now_mono`. `events[t] = fn(c)` pokes
+    the controller (stop, start, another writer) at that instant.
+
+    Returns [(t, grid, batt, setpoint, i_w, loop_reason, batt_refused)], the
+    number of gate trips, and the controller."""
+    async def go():
+        hass = _Hass(load, cut, cap)
+        c = Controller(dict(
+            {"setpoint_entity": "number.sp", "meter_entity": "sensor.grid",
+             "soc_entity": "sensor.soc", "batt_entity": "sensor.batt",
+             "meter_source": "off", "heartbeat_s": 10, "stale_input_s": 15},
+            **LIVE), hass, _Store(), _Pub(), stop=asyncio.Event())
+        c.auto = True
+        c.dev_min, c.dev_max = -LIVE["max_w"], LIVE["max_w"]
+        import app.main as m
+        real, real_dt = m.compute, m.datetime
+        clock = [0.0]
+
+        class _DT(real_dt):
+            """`cycle()`'s wall clock follows `now_mono`, so the 15 s input hold
+            and the gate's release run in simulated seconds too."""
+            @classmethod
+            def now(cls, tz=None):
+                return BASE + timedelta(seconds=clock[0])
+
+        m.datetime = _DT
+        if old:
+            m.compute = lambda *a, **k: real(*a, **dict(k, refused=None))
+        rows, trips, was = [], 0, False
+        try:
+            t = 0.0
+            while t < dur:
+                hass.t = clock[0] = t
+                for et, fn in list((events or {}).items()):
+                    if et <= t:
+                        fn(c)
+                        del events[et]
+                await c.read_inputs(now_mono=t)
+                stale = c.inverters[0].batt_fresh.stale
+                trips += stale and not was
+                was = stale
+                await c.cycle()
+                rows.append((t, hass.load(t) - hass.batt(), hass.batt(),
+                             hass.cmd, c.i_w, c.loop_reason, c.batt_refused))
+                t += TICK
+        finally:
+            m.compute, m.datetime = real, real_dt
+        return rows, trips, c
+    return asyncio.run(go())
+
+
+def at(rows, t):
+    return min(rows, key=lambda r: abs(r[0] - t))
+
+
+def longest_hold_h(rows, floor_w=250.0, until=None):
+    """Longest run of one identical request at or above `floor_w`, in hours."""
+    best = cur = 0.0
+    last = None
+    for r in rows:
+        if until is not None and r[0] >= until:
+            break
+        cur = cur + TICK if (r[3] == last and abs(r[3]) >= floor_w) else 0.0
+        last = r[3]
+        best = max(best, cur)
+    return best / H
+
+
+# ==============================================================================
+print("1. the 09-06 shape: a load step takes the request to 5000 W, the battery "
+      "cuts out, the load ends")
+# ==============================================================================
+def load906(t):
+    return 1020 if t < 60 else 4800 if t < 162 else 940 if t < 11.9 * H else -600
+
+
+def cut906(t):
+    return t >= 132
+
+
+def cap906(t):
+    return 4570.0
+
+
+old906, otrips906, _ = run(load906, cut906, 12.2 * H, cap906, old=True)
+new906, ntrips906, c906 = run(load906, cut906, 12.2 * H, cap906)
+for name, rows, tr in (("old", old906, otrips906), ("new", new906, ntrips906)):
+    print(f"    {name}: request at 2 min {at(rows, 120)[3]:+.0f} W, at 6 h "
+          f"{at(rows, 6 * H)[3]:+.0f} W (i_w {at(rows, 6 * H)[4]:+.0f}), longest "
+          f"hold {longest_hold_h(rows):.2f} h, gate trips {tr}")
+check("PRECONDITION: the old law holds +5000 W for the whole night on this "
+      "fixture, as it did on 2026-09-06 - the fixture reproduces the card",
+      at(old906, 6 * H)[3] == 5000.0 and longest_hold_h(old906) > 11.5)
+check("the request reaches the rail before the cut, so the new law starts from "
+      "the same place", at(new906, 120)[3] == 5000.0)
+t0 = next((r[0] for r in new906 if r[5] == REFUSED), None)
+check(f"after the cut the battery-refuses hold takes the request to 0 W within "
+      f"about a minute (at t={t0})", t0 is not None and 132 < t0 <= 132 + 90
+      and at(new906, t0)[3] == 0.0)
+check("...and it stays refused overnight, with the integrator at 0, and no "
+      "request of 250 W or more stands for longer than one probe interval",
+      at(new906, 6 * H)[6] == 1 and at(new906, 6 * H)[4] == 0.0
+      and longest_hold_h(new906, until=11.9 * H) < PROBE_EVERY_S / H)
+check(f"...and the stale-reading gate does not cycle: {ntrips906} trips in "
+      f"12 hours (the old law's latch also kept it quiet: {otrips906})",
+      ntrips906 == 0)
+morning = [r for r in new906 if r[0] >= 11.9 * H + 60]
+check("when solar makes the grid export, the refusal ends and the battery "
+      "charges - the exit on the other direction",
+      morning and morning[-1][6] == 0 and morning[-1][3] < -400)
+
+# ==============================================================================
+print("2. the probe: 200 W every 15 minutes, below the gate's 250 W")
+# ==============================================================================
+probes = []
+for r in new906:
+    if r[3] == PROBE_W and (not probes or r[0] - probes[-1][1] > TICK):
+        probes.append([r[0], r[0]])
+    elif r[3] == PROBE_W:
+        probes[-1][1] = r[0]
+starts = [p[0] for p in probes]
+gaps = [b - a for a, b in zip(starts, starts[1:])]
+print(f"    {len(probes)} probes, first at {starts[0] / 60 if starts else 0:.1f} "
+      f"min, gaps {sorted(set(round(g) for g in gaps))} s, lengths "
+      f"{sorted(set(round(p[1] - p[0] + TICK) for p in probes))} s")
+check("the probe asks exactly PROBE_W, which is below the stale-reading gate's "
+      "threshold, so a probe can never arm it",
+      PROBE_W < freshness.MOVE_W and all(r[3] in (0.0, PROBE_W)
+                                         for r in new906 if r[6] == 1))
+check("there is a probe every 15 minutes through the night (at least 40 in "
+      "11.8 hours), each about 34 s long",
+      len(probes) >= 40 and all(PROBE_EVERY_S <= g <= PROBE_EVERY_S + PROBE_S
+                                + 2 * TICK for g in gaps)
+      and all(PROBE_S - TICK <= p[1] - p[0] + TICK <= PROBE_S + TICK
+              for p in probes))
+check("...and a probe reads as a probe on the loop's own reason row",
+      any(r[5] == PROBING for r in new906))
+
+# ==============================================================================
+print("3. recovery with no sign change: the battery gives power again at 2 h")
+# ==============================================================================
+def cut_rec(t):
+    return 132 <= t < 2 * H
+
+
+oldr, _, _ = run(load906, cut_rec, 2.6 * H, cap906, old=True)
+newr, _, crec = run(load906, cut_rec, 2.6 * H, cap906)
+after_o = [r for r in oldr if 2 * H <= r[0] < 2 * H + 600]
+after_n = [r for r in newr if 2 * H <= r[0] < 2.6 * H]
+exp_o = sum(max(0.0, -r[1]) * TICK for r in after_o) / 3600
+exp_n = sum(max(0.0, -r[1]) * TICK for r in after_n) / 3600
+print(f"    old: worst grid {min(r[1] for r in after_o):+.0f} W, export "
+      f"{exp_o:.0f} Wh; new: worst grid {min(r[1] for r in after_n):+.0f} W, "
+      f"export {exp_n:.0f} Wh")
+check("PRECONDITION: the old law answers a recovering battery with its "
+      "standing +5000 W and exports kilowatts into a 940 W house",
+      min(r[1] for r in after_o) < -3000)
+check("the new law never exports more than the probe while it waits, and the "
+      "answered probe ends the refusal so control resumes",
+      min(r[1] for r in after_n) > -PROBE_W - 50
+      and after_n[-1][6] == 0 and abs(after_n[-1][1] - (-10)) < 100)
+check("...and the event log says the probe was answered",
+      any("BATTERY REFUSES ENDED: the probe was answered" in e
+          for e in crec.events))
+
+# ==============================================================================
+print("4. the 09-19 shape: a stale-reading stop on a frozen ~0 W reading "
+      "is a refusal")
+# ==============================================================================
+# The request steps +1540 -> +1940 and more as the battery cuts out mid-ramp:
+# the request moves after the reading went flat, so the gate trips before the
+# hold's 12 cycles - the ~70 s cycle SAFETY-59 measured. The trip seeds the hold.
+def load919(t):
+    return 1530 if t < 60 else 2400 if t < 1800 else 900 if t < 4 * H else -600
+
+
+def cut919(t):
+    return t >= 65
+
+
+def run919(old):
+    return run(load919, cut919, 4.2 * H, old=old)
+
+
+old919, otr919, _ = run919(True)
+new919, ntr919, c919 = run919(False)
+print(f"    old: gate trips {otr919}, longest hold {longest_hold_h(old919):.2f} h;"
+      f" new: gate trips {ntr919}, longest hold {longest_hold_h(new919):.2f} h")
+check("PRECONDITION: on the old law the gate trips over and over all night "
+      "(the SAFETY-59 cycle) or the request stands for hours",
+      otr919 > 20 or longest_hold_h(old919) > 1.0)
+check("the new law stops after at most two trips and holds 0 W, and the event "
+      "log says the battery refuses",
+      ntr919 <= 2 and at(new919, 2 * H)[3] in (0.0, PROBE_W)
+      and any("BATTERY REFUSES" in e for e in c919.events))
+
+# The same shape through `compute()` alone, as the bus saw it on 2026-09-19
+# before the gate existed: +1540 -> +1940, then a battery giving nothing.
+T = control.Tuning(**LIVE)
+res = {}
+for name, carry in (("old", None), ("new", 0)):
+    # sat_count 2: the +1540 and +1940 cycles were already short (the plan)
+    prev, i_w, sat, ref, cmds = 1940.0, 2340.0, 2, carry, []
+    for _ in range(2000):              # ~2.8 h at 5 s
+        d = control.compute(prev, 1950.0, CUT_W, T, sat, i_w, refused=ref)
+        prev, i_w, sat, ref = d.target_w, d.i_w, d.sat_count, d.refused
+        cmds.append(prev)
+    res[name] = cmds
+print(f"    compute() alone: old stands at {res['old'][-1]:+.0f} W "
+      f"({sum(v == 1940.0 for v in res['old'])} of 2000 cycles at +1940 W), "
+      f"new at {res['new'][-1]:+.0f} W from cycle "
+      f"{res['new'].index(0.0) if 0.0 in res['new'] else None}")
+check("PRECONDITION: without the gate the old law parks at +1940 W, the 7 065 "
+      "identical writes the bus recorded", set(res["old"]) == {1940.0})
+check("...and the new law holds 0 W within SETTLE_CYCLES cycles",
+      res["new"].index(0.0) < control.SETTLE_CYCLES
+      and set(res["new"][control.SETTLE_CYCLES:]) == {0.0})
+
+# ==============================================================================
+print("5. the other exits: stop, start, another writer")
+# ==============================================================================
+def stop(c):
+    c.auto = False
+
+
+def start(c):
+    c.auto = True
+
+
+rows, _, c = run(load906, cut906, 1200, cap906, events={600.0: stop,
+                                                         700.0: start})
+check("stopping control ends the refusal, and starting again begins from "
+      "nothing refused", at(rows, 590)[6] == 1 and at(rows, 650)[6] == 0
+      and at(rows, 705)[6] == 0)
+
+
+def other_writer(c):
+    c.loop_w = 1234.0      # the arbiter gave the wire something the loop did not ask
+
+
+rows, _, c = run(load906, cut906, 900, cap906, events={600.0: other_writer})
+check("another writer on the wire ends the refusal (the arbiter reseed)",
+      at(rows, 590)[6] == 1 and at(rows, 605)[6] == 0)
+
+# ==============================================================================
+print("5b. review of #141: a pack that gives SOME power, and a reading that is "
+      "only late, are not a refusal")
+# ==============================================================================
+# A pack derated to 100-499 W (cold, BMS taper) gives what it can against a
+# larger ask. Engaging below `saturation_w` (500 W) held it at 0 W for ~93 % of
+# the time; "gives nothing" is below the probe's own answer.
+# `compute()` alone: through the Controller the stale-reading gate trips on the
+# flat 300 W first, and that fixture then passes whatever this threshold is.
+def derated(carry, cap_w=300.0, n=1800):
+    prev, i_w, sat, ref, gave, held = 0.0, 0.0, 0, carry, 0.0, 0
+    b = 0.0
+    for _ in range(n):                                   # 2.5 h at 5 s
+        d = control.compute(prev, 2000.0 - b, b, T, sat, i_w, refused=ref)
+        prev, i_w, sat, ref = d.target_w, d.i_w, d.sat_count, d.refused
+        held += bool(ref)
+        b = max(0.0, min(prev, cap_w))                   # one tick late
+        gave += b
+    return gave / n, held
+
+
+T = control.Tuning(**LIVE)
+gave_old, _ = derated(None)
+gave_new, held_new = derated(0)
+print(f"    pack derated to 300 W: old law {gave_old:.0f} W average, new "
+      f"{gave_new:.0f} W, held as refusing on {held_new} cycles")
+check("a pack that gives a steady 300 W against a 2000 W ask is never held at "
+      "0 W as refusing, and keeps giving what the old law got from it",
+      held_new == 0 and gave_new == gave_old and gave_old > 290.0)
+
+
+def lagging(tick, dead_s=6.0, publish_s=10.0, phase_s=5.0, dur=600.0):
+    """`compute()` on a HEALTHY pack whose reading lags: it follows the command
+    of `dead_s` ago, published every `publish_s`. A 1 s meter (`meter_poll_s`
+    1) makes SETTLE_CYCLES only 12 s, shorter than that lag."""
+    prev, i_w, sat, ref, hist, reg, pub = 0.0, 0.0, 0, 0, [], 0.0, -phase_s
+    held = engaged = 0
+    t = 0.0
+    while t < dur:
+        then = [c for tc, c in hist if tc <= t - dead_s]
+        b = then[-1] if then else 0.0
+        if t - pub >= publish_s:
+            reg, pub = b, t
+        d = control.compute(prev, (3000.0 if t >= 10 else 0.0) - b, reg, T,
+                            sat, i_w, refused=ref)
+        engaged += bool(d.refused) and not ref
+        prev, i_w, sat, ref = d.target_w, d.i_w, d.sat_count, d.refused
+        hist.append((t, prev))
+        held += tick * bool(ref)
+        t += tick
+    return engaged, held
+
+
+lag1 = lagging(1.0)
+print(f"    1 s meter, healthy pack with a late reading: engaged {lag1[0]} "
+      f"time(s), held {lag1[1]:.0f} s")
+check("a healthy pack whose reading is merely late is let go as soon as the "
+      "reading shows it delivering - not held until the next probe",
+      lag1[1] <= 10.0)
+
+
+async def _seed(held_w):
+    """`_refusal_from_stale()` on a unit standing at +2000 W, frozen."""
+    c = Controller(dict(
+        {"setpoint_entity": "number.sp", "meter_entity": "sensor.grid",
+         "soc_entity": "sensor.soc", "batt_entity": "sensor.batt",
+         "meter_source": "off"}, **LIVE),
+        _Hass(lambda t: 0.0, lambda t: False), _Store(), _Pub(),
+        stop=asyncio.Event())
+    c.auto, c.sat_count = True, c.tuning.saturation_cycles
+    inv = c.inverters[0]
+    inv.last_write, inv.batt_fresh.held = 2000.0, held_w
+    c._refusal_from_stale(inv, 100.0)
+    return c.batt_refused
+
+
+check("a stale-reading stop on a register standing at 300 W is not a refusal "
+      "(it gives something), and one at -4 W is",
+      asyncio.run(_seed(300.0)) == 0 and asyncio.run(_seed(CUT_W)) == 1)
+d = control.compute(0.0, 1500.0, 1400.0, T, 0, 0.0, refused=1, probe=False)
+check("...i.e. a held direction that reads 100 W or more ends the refusal "
+      "without waiting for a probe", d.refused == 0)
+
+# ==============================================================================
+print("6. words")
+# ==============================================================================
+w = messages.why(why_key("loop", [Claim.set("loop", 0, 0.0, REFUSED)]), 0.0)
+wp = messages.why(why_key("loop", [Claim.set("loop", 0, PROBE_W, PROBING)]),
+                  PROBE_W)
+print(f"    {w!r} / {wp!r}")
+check("the page's Why line says the battery refuses, not 'Keeping the grid "
+      "near zero: 0 W'", w == "The battery refuses to give power: 0 W")
+check("...and a probe says what it is", wp.startswith("Testing if the battery"))
+check("...and an ordinary loop cycle still reads as the loop",
+      why_key("loop", [Claim.set("loop", 0, 10.0, "tracking")]) == "loop")
+
+print()
+if fails:
+    print(f"{len(fails)} FAILED: " + ", ".join(fails))
+    sys.exit(1)
+print("all checks passed")

goodwe_controller/tools/replay_refusal.py

@@ -0,0 +1,97 @@
+#!/usr/bin/env python3
+"""SAFETY-52's evidence: the 16-day capture replayed with and without the
+battery-refuses hold.  `python3 tools/replay_refusal.py`
+
+Same disturbance, fitted plant and pack floor as `replay_recorded_loop.py`,
+plus main.py's reseed, 15 s input hold and 0 W rules and the REAL SAFETY-37/57
+gate on a register published every 10 s. `old` is `compute()` with
+`refused=None`, which is release/1.0's law unchanged; `new` carries the refusal,
+runs the probe on main.py's clock and seeds a refusal from a gate trip.
+Modelled watt-hours: read the deltas, not the absolutes (see that tool).
+"""
+import math
+import pathlib
+import sys
+
+ADDON = pathlib.Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(ADDON))
+sys.path.insert(0, str(ADDON / "tools"))
+import replay_recorded_loop as R                            # noqa: E402
+from app import freshness, control as NEW                   # noqa: E402
+
+def go(which, rows, fit, publish_s=10.0, stale_input_s=15.0):
+    law = NEW
+    tun = law.Tuning(**R.LIVE)
+    t0, g0, b0, sp0, soc0 = rows[0]
+    pl = R.Plant(*fit[:4], soc0); pl.seed(t0, b0, sp0)
+    st = dict(target=sp0, i_w=sp0, sat=0, loop_w=sp0, ref=0, anchor=None)
+    fr = freshness.Freshness(freshness.BOUNDS["batt"]); reg, reg_t = None, -1e18
+    bad, trips, was = None, 0, False
+    M = dict(und=0.0, imp=0.0, exp=0.0, q={}, run=0.0, mx=0.0, last=None, refh=0.0, probes=0)
+    for i in range(1, len(rows)):
+        t, gr, ba, sp, soc = rows[i]
+        dt = t - rows[i - 1][0]
+        if dt > R.TICK_CAP_S:
+            pl = R.Plant(*fit[:4], soc); pl.seed(t, ba, sp)
+            st.update(target=sp, i_w=sp, sat=0, loop_w=sp, ref=0, anchor=None)
+            fr = freshness.Freshness(freshness.BOUNDS["batt"]); reg_t = -1e18; bad = None
+            continue
+        b = pl.step(t, dt, st["target"]); grid = gr + ba - b
+        if t - reg_t >= publish_s:
+            reg, reg_t = float(round(b)), t
+        fr.submit(reg, st["target"], t); batt = fr.reading()
+        if fr.stale and not was:
+            trips += 1
+            if (which == "new" and not st["ref"] and st["sat"] >= tun.saturation_cycles
+                    and abs(reg) < NEW.REFUSED_BELOW_W and abs(st["target"]) > tun.saturation_w):
+                st["ref"], st["anchor"] = (1 if st["target"] > 0 else -1), t
+        was = fr.stale
+        if batt is None:
+            bad = t if bad is None else bad
+            if t - bad >= stale_input_s:
+                st.update(target=0.0, i_w=0.0, loop_w=None)
+        else:
+            bad = None
+            if st["loop_w"] is None or st["target"] != st["loop_w"]:
+                st["i_w"] = st["target"]
+            if which == "old":
+                d = law.compute(st["target"], grid, batt, tun, st["sat"], st["i_w"],
+                                refused=None)
+            else:
+                probe = False
+                if st["ref"] and st["anchor"] is not None:
+                    h = t - st["anchor"]
+                    if h >= NEW.PROBE_EVERY_S + NEW.PROBE_S: st["anchor"] = t
+                    else: probe = h >= NEW.PROBE_EVERY_S
+                d = law.compute(st["target"], grid, batt, tun, st["sat"], st["i_w"], refused=st["ref"], probe=probe)
+                if d.refused and not st["ref"]: st["anchor"] = t
+                if not d.refused: st["anchor"] = None
+                if probe and d.target_w == NEW.PROBE_W and M["last"] != NEW.PROBE_W: M["probes"] += 1
+                st["ref"] = d.refused
+            st.update(sat=d.sat_count, i_w=d.i_w, loop_w=d.target_w, target=d.target_w)
+        tg = st["target"]
+        if tg - b > 1000: M["und"] += dt / 3600
+        if st["ref"]: M["refh"] += dt / 3600
+        M["imp"] += max(0, grid) * dt / 3.6e6; M["exp"] += max(0, -grid) * dt / 3.6e6
+        k = math.floor(t / 900); a = M["q"].setdefault(k, [0.0, 0.0]); a[0] += grid * dt; a[1] += dt
+        M["run"] = M["run"] + dt if (M["last"] == tg and abs(tg) >= 250) else 0.0
+        M["mx"] = max(M["mx"], M["run"]); M["last"] = tg
+    worst = max(max(0.0, s / d) for s, d in M["q"].values() if d > 600)
+    return trips, M, worst
+
+def main():
+    rows = R.stream()
+    fit = R.fit_plant(rows, stride=7)
+    print(f"fit {[round(x, 2) for x in fit]}, {len(rows)} meter instants")
+    for label, f in (("fitted plant", fit),
+                     ("plant offset 0 W", (fit[0], fit[1], fit[2], 0.0, fit[4]))):
+        for which in ("old", "new"):
+            tr, M, w = go(which, rows, f)
+            print(f"{label:17s} {which}: gate trips {tr:4d} | request >1 kW above "
+                  f"delivery {M['und']:6.1f} h | longest held >=250 W "
+                  f"{M['mx'] / 3600:5.2f} h | import {M['imp']:6.1f} kWh export "
+                  f"{M['exp']:5.1f} kWh | worst 15-min {w:5.0f} W | refused "
+                  f"{M['refh']:5.1f} h, probes {M['probes']}", flush=True)
+
+if __name__ == "__main__":
+    main()