chore(memory): LRN-207/208/209 + EVAL-041 — availability signal, blind security brief, scoped test runs, W1-C challenge value

.claude/memory/learnings.md

@@ -1765,3 +1765,15 @@ Rule: when editing a doctrine file under structure locks, grep the test's lock s
 - **Context**: model-router tests. Kit `$` is `EngineCall<E> = (e: Args<E>)`: `command.run` needs `origin` + `presentation`, `prompt.submit` needs `wait` + `origin`, `agent.spawn` needs `tool_use_id, description, provider, parentModel, background, fork`; the test file is type-checked with the hooks (tsc include). `session.start` does NOT fire at load → every test boots with a bottom `on('session.start')` + `$.session.start({ cwd, surface: null, isInteractive: false })`. A hook calling `next` hits the kit's bottom which throws unless the test registered one (`on('agent.spawn', ($, e) => ({ model: e.model, agentId: 'a1' }))`). `$.turn.step` returns a stream: drain with `for await` then await `.result` (awaiting `.result` alone runs no hook). No fs/network/process: defaults path only. Assert on the ONE line that carries the value (a `show()` listing every phase always contains every id and level).
 - **Apply**: write the boot helper first, type every input from the declarations, never relax a test to dodge a type. Links [[BDR-115]].
 
+## LRN-207 — Model availability = typed API errors (`classic.StopFailure` rate_limit|overloaded|billing_error|model_not_found) + `PostModelSwitch auto`; never the turn-end reason, never `rateLimits`; sticky state and breaker target = two fields
+- **Context**: model-router W1-C. `turn.complete reason: error` covers context-limit and network errors → a breaker fed by it marked fable down 15 min on a context overflow (challenge r1). `rateLimits` kinds are account windows (five_hour, seven_day, spend_limit), not per model. A per-step "engine fallback detection" (`e.model` ≠ `$.session.model()`) re-marked the session model at EVERY step → backoff climbed to the 5 h cap in one turn (confirmation r2). One field used both as sticky cur and as breaker target contradicted itself (reset at turn end vs kept).
+- **Apply**: feed a breaker only from typed error kinds that name unavailability; mark per EPISODE (idempotent while down), backoff 15→300 min, `model_not_found` until reload; a user `/model` clears, `/clear` keeps (account-wide). Keep `turnModel` (sticky, reset per turn) and `lastPlan` (breaker target, kept) separate; unrouted steps pass `e.model` verbatim so the engine's own fallback is respected. Links [[BDR-115]], [[LRN-204]].
+
+## LRN-208 — Security-auditor brief = scope only; iteration history and claimed closures violate the blind-scan contract
+- **Context**: W1-C gate 2026-10-09. I sent "previous PASS with 6 MEDIUM, closed: …" in the brief. Auditor: "The auditor contract says that is never sent and must be ignored … Please do not send it next time" (it scanned blind anyway). Same rule as the verifier (lib/verify-secure-loop.md: fresh, no history).
+- **Apply**: SCOPE + a neutral CONTEXT of what the code does; never prior verdicts, closures or accepted residuals. Residuals live in TODO, the auditor rediscovers them (that is the point). Links [[LRN-083]].
+
+## LRN-209 — Scope the test run to the diff; one full `make test` before the merge; `make test` now names the red suite; GNU make rc 2 on a failed recipe
+- **Context**: 2026-10-09 the pre-merge check took 454 s = full `make test` (48 suites) + a per-suite re-run to NAME the red one (aggregate rc, permanent env red design-tool-gate). Three more full passes earlier that day for mods/-only diffs. Hotfix efdd491: the recipe prints `FAIL <suite>` + `all suites green` / `<n> suite(s) red: …`. My oracle expected rc 1; GNU make returns 2 when a recipe line fails.
+- **Apply**: a diff confined to one component runs that component's suite + the doctrine census; the full suite runs ONCE before `gitflow finish`; read the FAIL lines, never re-run per suite. Oracles on `make` test `[ $rc -ne 0 ]`, not `-eq 1`. Links [[LRN-173]].
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