SAFETY-26's AC4 gave the same tolerance mutation to every price and quantity
boundary in arbitrage.py and static_tariff.py. Everything in arbitrage.py went
red - `price < 0`, `soc <= floor_pct`, `soc >= ceiling_pct` are each red under
+/-5. Two survived, both in static_tariff.py, and this card closes them.
D `spread == 0.0` (:912) weakened to `spread <= 0.001` SURVIVED at +2 B.
F `len(firm) < 2` (:901) weakened to `len(firm) < 1` SURVIVED at +0 B - the
delta MUTATION.md names as the risky one.
THE DEFECT IS NOT EITHER ROW, IT IS THE INTERACTION. D and F MASK EACH OTHER. A
single firm hour also has a spread of 0.0, so with F weakened the flat rung
refuses the stimulus anyway; with D weakened the small-but-real spread is still
refused, only for a lie. Each rung's failure is absorbed by the other, so BOTH
can be weakened together and a suite grading `kind == "refused"` reports
nothing. That is structurally invisible to single-mutation testing, which is how
this pair came through four rounds of review on TARIFF-03 and FCST-03 - and it
is the arrangement in which the next edit to either rung opens a real hole with
nothing to report it.
D is not cosmetic either. With the tolerance in place a series priced 0.20000 /
0.20050 - a REAL 0.0005 EUR/kWh spread - flips ALLOWED to REFUSED at
min_spread_eur_kwh=0.0, a value arbitrage()'s own docstring documents ("pass 0.0
to mean any positive spread, explicitly") and its validator at :861 accepts on
purpose. At a shipped threshold the outcome does not move, but the operator
reads the false sentence "the tariff is flat - every one of the 2 firm hours
costs 0.2000 EUR/kWh" about a tariff that is not flat.
WHAT WAS ADDED. test_static_tariff.py section 9, and the shape of it is the
argument:
* THE REASON IS GRADED, NOT THE VERDICT. The masked case refuses CORRECTLY
while reporting the wrong sentence, so a check asserting only "refused"
passes on a broken tree. A `rung9()` helper names which refusal answered,
from the sentence the operator would read; an unrecognised refusal reports
itself as UNATTRIBUTED rather than quietly matching nothing.
* EACH RUNG IS GIVEN A STIMULUS THE OTHER CANNOT ABSORB, or the pinning is
circular. The flat rung gets a THREE-firm-hour flat series, which no
`len(firm) < N` a person would write can reach. The firm-pair rung gets a
ONE-FIRM-HOUR series, which the flat rung CAN reach - so its attribution is
the whole check, and that is why it is written as a rung name rather than a
verdict.
* AC1 is a sweep of small-but-real spreads (0.0005 down to 0.000001) all
ALLOWED at min_spread_eur_kwh=0.0, with the exactly flat series on the other
side still refused BY THE FLAT RUNG - without that mirror the sweep would
also pass for a rung deleted outright. 1e-6 is the floor because the shipped
line rounds the spread to 6 decimals; that quantisation is graded in the
open as its own row rather than left unstated.
* AC3 is a five-row table graded on rung attribution, which denies the masking
from both sides at once.
* The firm-pair count is also pinned from ABOVE (`< 3`) and BELOW (`< 0`),
which the criteria do not ask for but which is what stops this section being
one-sided in exactly the way it was written to fix.
EVIDENCE. Eight rounds through TEST-15's tools/mutation_run.sh, used UNCHANGED:
recursive __pycache__ purge before each run, python3 -B, the tree re-copied FROM
DISK between rounds, the mutated line grepped out of the file before the run,
byte delta printed, test_static_tariff.py and test_arbitrage.py graded each
time. Baseline green.
baseline, shipped +0 B PASS
D1 `spread == 0.0` -> `<= 0.001` +2 B RED, 3 checks
D2 `spread == 0.0` -> `<= 0.000001` +5 B RED, AC1 alone
D3 `spread == 0.0` -> `< 0.0` (rung gone) +0 B RED (section 2 as well)
F1 `len(firm) < 2` -> `< 1` +0 B RED, 3 checks
F2 `len(firm) < 2` -> `< 3` +0 B RED, 6 checks
F3 `len(firm) < 2` -> `< 0` (rung gone) +0 B RED (ValueError)
D1+F1 BOTH AT ONCE - THE TICKET +2 B RED, 5 checks
Four of the seven are +0 B, the delta MUTATION.md names as the one stale
bytecode can hide. All are REDS, the direction that defect cannot fabricate -
but they were run under the purge anyway, because "it went red so the cache
cannot have lied" is a conclusion and not a procedure.
NO SHIPPED BEHAVIOUR CHANGED. app/ is untouched; both rungs were correct all
along, and the card is explicit that a rung found actually wrong is a stop-and-
report rather than an edit. Also updated: MUTATION.md gains a short section on
masking as a SECOND way a survivor lies, with the two rules that fall out of it
(grade the reason, and mutate suspected pairs together); and test_arbitrage.py's
SAFETY-26 AC4 note is marked closed rather than left reading as an open finding.
UNSURE ABOUT. The 5e-7 row asserts the shipped `round(spread, 6)` quantisation.
That is a real property of the line and worth stating, but it does pin a
rounding the ticket never named - if a reviewer would rather that stayed
unpinned, it is one check to drop and nothing else depends on it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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.