release(v0.5.1): hotfix — quota probe cache/backoff/schema-drift correctness (codex review) (#58)

* release(v0.5.1): hotfix — quota probe cache/backoff/schema-drift correctness (codex review)

Addresses three production-quality findings from codex's post-v0.5.0 review (codex review on
PR #57, reproduced with local mocks):

F1 [P1] — Doctor bypass of cache + backoff (ADR 0013 Rule 3)
  `anthropic.quota_probe_reachable` called `_probeOnce(auth)` directly, bypassing
  `quotaProbeState.backoffUntil`. Successive `olp doctor` invocations within a backoff
  window each hit upstream — violating ADR 0013 Rule 3 (backoff is mandatory for ALL
  consumers). Fix: doctor now routes through `quotaStatus()`. ADR 0013 Rule 3 clarified:
  "All consumers of `quotaStatus()`, including `olp doctor` checks, MUST route through
  `quotaStatus()` and MUST NOT call `_probeOnce()` directly."

F2 [P2] — 200 with empty ratelimit headers cached as live data (ADR 0013 Rule 5)
  A 200 OK with zero `anthropic-ratelimit-*` headers was cached as `stale: false` (live).
  Minimum-viable-schema gate added to `_probeOnce`: requires 5h-utilization + 5h-reset +
  7d-utilization + 7d-reset present; absence → `failureKind: 'schema_drift'`, backoff
  scheduled, result NOT cached. ADR 0013 Rule 5 updated with the gate specification.

F3 [P2] — Dashboard-data loses failure detail (ADR 0013 Rule 6)
  `aggregateProviderQuota()` collapsed all failure modes into `status: 'unavailable'`
  ("no public quota api or probe disabled") — same as providers with no API at all.
  Fix: `quotaStatus()` v0.5.1 contract — `null` ONLY for opt-in-off; failures return
  `{ probe_status: 'unreachable', failure: { kind, message, backoff_until? } }`.
  New `failure_kind` enum: no_credentials | auth_failed | rate_limited | schema_drift |
  network | other. Dashboard renders `unreachable` with red border + failure detail.

Authority:
  ADR 0013 Rules 3, 5, 6 (cache + backoff + schema-drift + failure transparency)
  ADR 0008 Amendment 2 (richer quota_v2 shape; new unreachable status)
  ADR 0002 Amendment 8 unchanged (constitutional permission for the probe)
  Codex review findings F1–F3 (codex on PR #57)

Changes:
  - lib/providers/anthropic.mjs: quotaProbeState gains lastError + failureKind;
    _probeOnce: min-field gate + failureKind population; quotaStatus(): v0.5.1 contract
    (null=disabled only; probe_status:live/stale/unreachable); doctorChecks routes
    through quotaStatus(); reset functions updated
  - lib/audit-query.mjs: _normalizeAnthropicQuota handles probe_status field;
    aggregateProviderQuota emits failure/failure_kind/backoff_until; unreachable status
  - dashboard.html: unreachable CSS classes + render path + footer v0.5.1
  - test-features.mjs: 38f/j/l updated for v0.5.1 shape; 38r refactored for F1;
    38g/k gain probe_status assertions; 38u/v/w new regression tests; 756→759 tests
  - docs/adr/0008: Amendment 2 (richer ProviderQuotaEntry + quotaStatus contract)
  - docs/adr/0013: Rule 3 clarification (doctor must use quotaStatus);
    Rule 5 min-viable-schema gate specification
  - package.json: 0.5.0 → 0.5.1
  - CHANGELOG.md: v0.5.1 hotfix entry promoted from Unreleased
  - README.md / AGENTS.md: Phase 5 closed at v0.5.1; Phase 6 next

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* docs+code: PR #58 fold-in — reviewer Nits #1 + #2 (ADR doc-drift + opt_in_off enum)

Fresh-context reviewer (PR #58) verdict: APPROVE_WITH_MINOR, 0 blocking,
4 nits. Folding in #1 + #2 (both 1-line cosmetic-but-correct fixes).
Deferring #3 (test-only edge case in module-level seam restore) and #4
(pre-existing codex F4 — bin/olp.mjs + olp-plugin still read legacy
quota shape; separate PR planned).

Nit #1 — ADR 0002 Amendment 8 documentation drift.

Amendment 8 at v0.5.0 line 20 said "the function returns `null` rather
than throwing", and line 33 said "stale-cache-on-failure (`null` is
returned only when no cache entry exists; if a stale entry exists it's
returned with a `stale: true` marker)". v0.5.1 refined this contract:
`null` is now reserved STRICTLY for opt-in-off, and all failure modes
return `{ probe_status: 'unreachable' | 'stale', failure: {...} }`.

The substantive idempotent-failure constraint (no throw to caller) is
unchanged. The operational description in Amendment 8 was stale — fixed
to cross-reference ADR 0008 Amendment 2 + ADR 0013 Rule 6 for the
v0.5.1 contract refinement. Also references Suite 38 (38u/38v/38w) as
the regression coverage producing the new shape.

Nit #2 — `failureKind: 'opt_in_off'` declared but never produced.

The enum value was listed in both the code comment (anthropic.mjs:250)
and ADR 0008 Amendment 2 (line 30) but never actually assigned —
because when opt-in is off, `quotaStatus()` returns the literal `null`
BEFORE any state mutation happens. The enum value was dead.

Fix: removed `opt_in_off` from both enum declarations + added an
inline note explaining that consumers (audit-query, doctor) distinguish
opt-in-off by checking `quotaStatus() === null`, not via failureKind.

Deferred:

- Nit #3 (test-seam restore edge case): if a caller pre-sets
  `_quotaAuthReadFnForTest` AND passes a non-default `_authReadFn`,
  the finally block restores to null clobbering pre-set value.
  Test-only impact, no production risk. Pure hygiene; defer.

- Nit #4 (codex F4): bin/olp.mjs cmdUsage and olp-plugin/index.js
  still read legacy `body.quota` field, never consume `quota_v2`.
  Reviewer confirmed neither crashes — both gracefully fall through
  to "no quota api" branch. Out of scope for this hotfix per the
  hotfix dispatch contract; separate PR will migrate them.

Tests: 759/759 still pass post-fold-in. No test changes needed.

Authority: PR #58 review thread + ADR 0013 Rule 6 (failure transparency)
+ ADR 0008 Amendment 2 (ProviderQuotaEntry v0.5.1 shape).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

---------

Co-authored-by: dtzp555 <dtzp555@gmail.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/adr/0013-oauth-read-only-consumption-and-schema-drift.md

@@ -47,9 +47,10 @@ The probe MUST NOT call any other HTTP path on the provider's API. No `/v1/model
 
 - Cache TTL: 5 minutes. Cache miss triggers a real probe. Cache hit returns the cached value.
 - The dashboard refreshes every 1 minute; that's served from the cache between probes. A manual refresh button MAY force-clear the cache (per maintainer request 2026-05-26); ADR 0012 D82 documents the button.
-- On refresh failure (token expired, 401/403/429, network error), the probe schedules an exponential backoff: minimum 60s, maximum 3600s. The cache entry is NOT invalidated during backoff; `quotaStatus()` returns the stale cache marked `{ stale: true, last_fresh_at: <epoch> }`. If no stale entry exists, returns `null`.
+- On refresh failure (token expired, 401/403/429, network error), the probe schedules an exponential backoff: minimum 60s, maximum 3600s. The cache entry is NOT invalidated during backoff; `quotaStatus()` returns the stale cache marked `{ stale: true, last_fresh_at: <epoch> }`. If no stale entry exists, returns an `unreachable` shape (v0.5.1+) rather than `null`.
 - Successive successful probes reset the backoff to the minimum.
 - Token refresh (`POST https://platform.claude.com/v1/oauth/token`) follows the same backoff discipline. The probe MUST NOT refresh a token more than once per backoff window. The refresh path is shared with the spawn path; both observe the same backoff.
+- **All consumers of `quotaStatus()`, including `olp doctor` checks, MUST route through `quotaStatus()` and MUST NOT call `_probeOnce()` directly.** `_probeOnce()` is an internal implementation detail. Routing doctor checks through `quotaStatus()` ensures the cache+backoff discipline is enforced for every caller — including operators running `olp doctor` in a debug loop. (Clarification added v0.5.1 to address codex finding F1: the original doctor check bypassed backoff by calling `_probeOnce` directly.)
 
 ### Rule 4 — Opt-in via config
 
@@ -70,7 +71,17 @@ Default: `false`. The maintainer must explicitly opt in after credentials are co
 
 `olp doctor` adds a per-provider check `<provider>.quota_probe_reachable` (only runs if `quota_probe_enabled: true`). Failed check provides a `next_action.ai_executable[]` recipe to either re-authenticate or disable the probe.
 
-### Rule 5 — Schema-drift mitigation protocol
+### Rule 5 — Schema-drift mitigation protocol (minimum-viable-schema gate)
+
+The CC binary-distribution shift means OCP's "grep cli.js" verification is no longer applicable. OLP adopts a two-path protocol for proactive monitoring, AND enforces a minimum-viable-schema gate at parse time:
+
+**Minimum-viable-schema gate (v0.5.1+).** `_probeOnce()` requires at least these 4 fields present (non-null after parse) before treating a response as successful:
+- `anthropic-ratelimit-unified-5h-utilization`
+- `anthropic-ratelimit-unified-5h-reset`
+- `anthropic-ratelimit-unified-7d-utilization`
+- `anthropic-ratelimit-unified-7d-reset`
+
+If any of these 4 is absent, `_probeOnce()` classifies the probe as a schema-drift failure (`failureKind = 'schema_drift'`), schedules backoff, and returns `null`. This means a 200 OK with zero `anthropic-ratelimit-*` headers (e.g. a server-side change, a proxy stripping headers, or a mock returning `{}`) is immediately caught as drift rather than silently cached as "live" data. The other 9 fields are tolerated as absent (overage fields are conditional; top-level status fields may be absent on edge cases). The 5h/7d core 4 are load-bearing — the dashboard's progress bars depend on them. (Gate added v0.5.1 to address codex finding F2.)
 
 The CC binary-distribution shift means OCP's "grep cli.js" verification is no longer applicable. OLP adopts a two-path protocol: