main.py used to read the setpoint device's own +-5000 W rating, notice a
configured max_w above it, log one WARNING, and run anyway with
write_setpoint() quietly clamping. The operator's stated ceiling was never
the real ceiling and the only evidence had scrolled off the log. specs
§1.5 is explicit that such a config is refused at startup, not survived at
runtime.
validate_startup_config() runs in amain() before the broker, the web
server or any task exists, so a refusal cannot leave half a controller
running behind a UI. It refuses exactly three things, all sharing one
property - continuing makes a safety mechanism inoperative or makes a
stated limit untrue:
1. max_w outside the setpoint device's own rating.
2. No setpoint_entity: every write is a no-op, the device rating is
never read, and the ESP32 heartbeat that holds off the layer-1
failsafe never happens. It ran, looked healthy, and moved nothing.
3. A meter_source that can never produce a reading. These were already
caught, but they only DISABLED ingestion, which leaves grid None
forever: permanent inputs-missing, 0 W, and a status page
indistinguishable from a healthy meter nobody has fed yet.
Those last predicates move into p1.validate_meter_options(), which
build_source() also calls - one definition, two callers, not two
competing validators. ha_dsmr with half its entities and mqtt_p1 with a
blank topic gained the check the other two transports already had.
Deliberately not refused, because untidy is not unsafe: integrator_max_w
above max_w (the arbiter still bounds the wire to +-max_w, so the cost is
unwind latency - warned), a missing soc/batt entity (fail-safe and
already a red NOT READY banner), a setpoint entity that has not appeared
on the Core API yet (ESPHome is routinely late; re-checked in
run_control() once the real rating arrives), and a thin meter_poll_s
margin.
A refusal is legible as one: a banner saying in words that this is
configuration and nothing is broken, numbered problems, no traceback, and
exit 78 (EX_CONFIG).
Verified on the live add-on 2026-08-28, not by reading the code: a blank
setpoint_entity and a meter_poll_s equal to meter_max_age_s each stopped
the add-on with the banner and no stack trace.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Du77usMj8XNKNFZGmUiWDa
