chore(drift): classify claude-opus-5 in includeFamilies (live GA text chat)

[jpr5]

What was unclassified

claude-opus-5 — Claude Opus 5 — is an unclassified Anthropic model family on main. It appears in Anthropic's live GET /v1/models listing but is in neither includeFamilies.anthropic nor excludeFamilies.anthropic, so the live /models family canary flags it as a new-family decision and re-routes it to a human on every run.

It was simply missed: the last classification wave (34056c2) covered the 2026-07-16 listing, and Opus 5 landed after it (created_at: 2026-07-24).

Only this one family is unclassified. The live listing returns 11 ids and every other one is already classified — including the other two Claude-5 members, claude-sonnet-5 and claude-fable-5. So this is a one-family fix, not a wave.

Evidence it was unclassified

Live listing (GET https://api.anthropic.com/v1/models, fetched 2026-07-24, key sourced from the session secret cache — never persisted anywhere):

count 11  has_more False
  claude-opus-5              | Claude Opus 5    | 2026-07-24T00:00:00Z   <-- unclassified
  claude-sonnet-5            | Claude Sonnet 5  | 2026-06-29T00:00:00Z
  claude-fable-5             | Claude Fable 5   | 2026-06-07T00:00:00Z
  claude-opus-4-8            | Claude Opus 4.8  | 2026-05-28T00:00:00Z
  claude-opus-4-7            | Claude Opus 4.7  | 2026-04-14T00:00:00Z
  claude-sonnet-4-6          | Claude Sonnet 4.6| 2026-02-17T00:00:00Z
  claude-opus-4-6            | Claude Opus 4.6  | 2026-02-04T00:00:00Z
  claude-opus-4-5-20251101   | Claude Opus 4.5  | 2025-11-24T00:00:00Z
  claude-haiku-4-5-20251001  | Claude Haiku 4.5 | 2025-10-15T00:00:00Z
  claude-sonnet-4-5-20250929 | Claude Sonnet 4.5| 2025-09-29T00:00:00Z
  claude-opus-4-1-20250805   | Claude Opus 4.1  | 2025-08-05T00:00:00Z

Independently corroborated by PR #337's drift-live-pr job, whose uploaded head and base drift reports both contain exactly one entry — this same finding — with conclusion: critical. It passed #337's delta gate only because that gate is new-in-head-only, so the finding has been sitting on main unaddressed.

Classification chosen, and why

includeFamilies.anthropic (src/__tests__/drift/model-registry.ts:132), under the existing // Claude 5 families (text chat) comment.

Justification from the code, not from vibes:

• includeFamilies is documented as "families aimock actually MOCKS … chat / text completion families" (model-registry.ts:16-20). Opus 5 is a GA text-chat/reasoning model on the live listing — squarely that category.
• Every GA text-chat Claude family on the live listing is in includeFamilies.anthropic. excludeFamilies.anthropic holds only retired/legacy ids (claude-v3, claude-2, claude-instant-1, model-registry.ts:217-222). Opus 5 is brand new, not retired, so exclude would be wrong.
• Direct sibling precedent: claude-sonnet-5 and claude-opus-4-8 are both includeFamilies entries added by 34056c2 ("INCLUDE (text chat / reasoning aimock mocks): … Anthropic all 4.x/5 point releases"). Opus 5 is the same class of thing.
• It is not a preview and not Gemma, so neither exclude-by-rule predicate (PREVIEW_FAMILY, GEMMA_FAMILY) applies.

Reasoning vs non-reasoning: reasoning-capable, and no code change needed

isReasoningModel("claude-opus-5") already returns true, before and after this PR. Verified empirically (not reasoned) by driving the real src/model-utils.ts export on both tree states:

                            PRE-fix   POST-fix
  claude-opus-5           ->  true      true
  claude-opus-5-20260724  ->  true      true
  claude-sonnet-5         ->  true      true
  claude-fable-5          ->  true      true
  claude-opus-4-8         ->  true      true
  claude-opus-4           ->  true      true
  claude-3-5-sonnet       ->  false     false     (control)
  claude-3-opus           ->  false     false     (control)

true is the correct verdict for an extended-thinking Opus-class model. It arrives via the documented fail-open default (model-utils.ts:18-26, 135-136): no NONREASONING_FAMILIES prefix matches claude-opus-5, and REASONING_FAMILIES' claude-opus-4 entry does not prefix-match claude-opus-5 either, so it falls through to true.

So src/model-utils.ts is deliberately untouched. Adding a REASONING_FAMILIES entry would be a no-op — that list is explicitly "mostly documentation; because unknown ids default to true it is not load-bearing for correctness" (model-utils.ts:21-22) — and it would break the precedent that claude-sonnet-5 and claude-fable-5 also rely on the default rather than an explicit entry. Touching shipped source for a zero-delta documentation edit would turn a registry-only change into a src change for no benefit.

Mock / fixture support: none needed

Registry classification alone is sufficient, and this PR does not claim support aimock lacks.

aimock's Anthropic surface is fixture-driven and model-agnostic — it matches on request content, not on model id. Probed the built dist/ with real HTTP requests against a running server:

POST /v1/messages {"model":"claude-opus-5",   ...}  -> {"error":{"message":"No fixture matched", ...}}
POST /v1/messages {"model":"claude-sonnet-5", ...}  -> {"error":{"message":"No fixture matched", ...}}

Byte-identical behavior to the already-included claude-sonnet-5: with a matching fixture loaded both serve it, without one both report No fixture matched. No per-family code path exists, so there is nothing family-specific to add. DEFAULT_MODELS (src/server.ts:227) is a separate static 5-id list that this registry does not feed and that no Claude-5 family was ever in.

This is exactly the situation the existing claude-fable-5 comment already documents — a family included ahead of a recorded fixture, intentionally.

RED → GREEN

The failure surface is the real live drift leg: src/__tests__/drift/models.drift.ts:606-618, describe.skipIf(!process.env.ANTHROPIC_API_KEY), which calls listAnthropicModels() against the real API and asserts through assertNoUnclassifiedFamilies. It gates on ANTHROPIC_API_KEY and is SKIPPED without one, so reproducing the RED below requires credentials; a bare checkout silently skips it. A credential-free leg is included after.

RED — unmodified main (d1b5304), live API

$ pnpm exec vitest run --config vitest.config.drift.ts \
    src/__tests__/drift/models.drift.ts -t "live /models contains no unclassified family"

 × Anthropic Claude model-family availability > live /models contains no unclassified family 499ms
   →
API DRIFT DETECTED: Anthropic Claude (live /models family canary)

  1. [critical] Unclassified model family "claude-opus-5" in anthropic /models — add it to includeFamilies (aimock mocks it) or excludeFamilies (non-text / retired / preview) in model-registry.ts
     Path:    models/claude-opus-5
     SDK:     (family in includeFamilies ∪ excludeFamilies)
     Real:    claude-opus-5
     Mock:    <no mock leg — live /models family canary>
: expected [ 'claude-opus-5' ] to deeply equal []

 ❯ assertNoUnclassifiedFamilies src/__tests__/drift/models.drift.ts:95:32
 ❯ src/__tests__/drift/models.drift.ts:611:7

 Test Files  1 failed (1)
      Tests  1 failed | 24 skipped (25)

GREEN — same command, after the classification

$ pnpm exec vitest run --config vitest.config.drift.ts \
    src/__tests__/drift/models.drift.ts -t "live /models contains no unclassified family"

 ✓ src/__tests__/drift/models.drift.ts (25 tests | 24 skipped) 506ms
   ✓ Anthropic Claude model-family availability > live /models contains no unclassified family  505ms

 Test Files  1 passed (1)
      Tests  1 passed | 24 skipped (25)

Credential-free corroboration

Driving the pure mirror unclassifiedFamiliesForSync (scripts/drift-sync.ts) over the captured live payload, on both tree states:

captured LIVE anthropic /models ids (11): ["claude-opus-5","claude-sonnet-5","claude-fable-5",
  "claude-opus-4-8","claude-opus-4-7","claude-sonnet-4-6","claude-opus-4-6",
  "claude-opus-4-5-20251101","claude-haiku-4-5-20251001","claude-sonnet-4-5-20250929",
  "claude-opus-4-1-20250805"]

PRE-fix : unclassifiedFamiliesForSync(anthropic) = ["claude-opus-5"]   claude-opus-5 flagged = true
          includeFamilies.anthropic.has('claude-opus-5') = false
POST-fix: unclassifiedFamiliesForSync(anthropic) = []                  claude-opus-5 flagged = false
          includeFamilies.anthropic.has('claude-opus-5') = true
          excludeFamilies.anthropic.has('claude-opus-5') = false

Membership pin RED → GREEN

The DATA_FROZEN canary correctly tripped on the deliberate addition:

 × classification-data membership freeze > freezes includeFamilies.anthropic membership 5ms
   → Frozen data set "includeFamilies.anthropic" membership changed (now: ["claude-3-5-haiku",
     "claude-3-5-sonnet","claude-3-7-sonnet","claude-3-haiku","claude-3-opus","claude-3-sonnet",
     "claude-fable-5","claude-haiku-4","claude-haiku-4-5","claude-opus-4","claude-opus-4-1",
     "claude-opus-4-5","claude-opus-4-6","claude-opus-4-7","claude-opus-4-8","claude-opus-5",
     "claude-sonnet-4","claude-sonnet-4-5","claude-sonnet-4-6","claude-sonnet-5"]). If this is a
     deliberate, reviewed addition/removal of a classified family, update its pin here; if not,
     it is a silent canary-silencing edit and must be reverted.
     Expected: "dbd8b4ef9afd50057143480d89db373886e7c19abe36ef9b4421456305ca2509"
     Received: "ab79ff332fadeff93c2678ebe3e0af7a6280ce6f0deb4694228e316944dfeb74"

 Test Files  1 failed (1)
      Tests  1 failed | 19 passed (20)

The new pin was derived independently, not copied from vitest's Received. Reimplemented the test's own hashing (sha256(JSON.stringify(members.sort())), logic-pin.test.ts:59-61 + :227) in a standalone script, and first validated the method by reproducing the pre-existing pin exactly:

PRE  derived : dbd8b4ef9afd50057143480d89db373886e7c19abe36ef9b4421456305ca2509
PRE  in-repo : dbd8b4ef9afd50057143480d89db373886e7c19abe36ef9b4421456305ca2509
PRE  METHOD VALIDATED: True
POST derived : ab79ff332fadeff93c2678ebe3e0af7a6280ce6f0deb4694228e316944dfeb74

Three-way agreement (derived / vitest Received / committed value). After re-pinning:

 ✓ src/__tests__/drift/logic-pin.test.ts (20 tests) 3ms
 Test Files  1 passed (1)
      Tests  20 passed (20)

Full suite — zero regressions

$ pnpm test
 Test Files  166 passed (166)
      Tests  4768 passed | 3 skipped (4771)

Versioning verdict: no bump, no changeset

No behavior change, so nothing to release. Three independent confirmations:

1. No shipped importer. Every importer of model-registry.ts is a test or a repo script (scripts/drift-sync.ts, scripts/drift-sync-check.ts, and six src/__tests__/ files). Non-test, non-script importers: none. src/model-utils.ts, src/server.ts and the tsdown entrypoints never touch it — includeFamilies/excludeFamilies are drift metadata, not a runtime allowlist.
2. Absent from the published tarball, and not inlined. package.json files is an allowlist (["dist","fixtures",".claude-plugin","skills","CHANGELOG.md"]); npm pack --dry-run yields 576 files with 0 matching __tests__ / logic-pin / model-registry / src/. dist/ contains zero occurrences of includeFamilies, excludeFamilies, or claude-opus-5.
3. Built artifact semantically identical. Compared pre-fix and post-fix dist/, normalizing the two known non-reproducible-build artifacts this repo has (tsdown's import-alias numbering, e.g. node_http0 vs node_http1, and declaration sourcemaps), with two identical-source builds as the noise floor:

noise floor (identical source):
  CONTROL: POST vs CTRL      files=285 differing=0 setdiff=0
subject:
  SUBJECT: PRE-fix vs POST-fix   files=285 differing=0 setdiff=0
VERDICT: PUBLISHED ARTIFACT SEMANTICALLY IDENTICAL

Release mechanism is a manual package.json version bump consumed by publish-release.yml; there is no Changesets / release-please / semantic-release, and no workflow derives a version from commit messages. chore(drift): is therefore the honest prefix — this is a classification-only change with zero behavior delta, so neither feat nor fix is warranted.

Pre-push gates

$ pnpm format:check      → All matched files use Prettier code style!
$ pnpm lint              → clean
$ pnpm exec tsc --noEmit → clean
$ pnpm test              → 166 files passed, 4768 passed, 0 failed
$ pnpm build             → ✔ Build complete
$ pnpm test:exports      → node10 🟢  node16 CJS 🟢  node16 ESM 🟢  bundler 🟢
$ pnpm exec commitlint --from HEAD~1 --to HEAD → clean

Pre-existing caveat (not introduced here)

.github/workflows/unreleased-check.yml counts commits touching src/ since the last tag without excluding src/__tests__/, so on merge it will emit ::warning:: … version has not been bumped. It is a warning with no exit 1 and does not fail CI. #336 and #337 have the same shape.

Live-CI RED → GREEN (added after CI ran)

drift-live-pr runs the drift suite against the real provider /models listings and uploads a base and a head report. On this PR (run 30132383648) those two artifacts are themselves the red-green, from CI rather than from my machine:

BASE (main @ d1b5304)                    HEAD (this PR)
  "conclusion": "critical"                 "conclusion": "clean"
  entries: 1                               "entries": []
    - critical | claude-opus-5

main is measurably red on this finding right now; this branch is clean. Full CI: 26 pass, 2 skipping, 0 fail (28 rows).

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@copilotkit/aimock@339

commit: 72f85f8