test: accept any first city in the Vertex K5 interpreter anomaly

[jpr5]

What

The Vertex K5 interpreter-anomaly check in src/__tests__/drift/vertex-misbehavior.drift.ts matched only two first cities, Tokyo and London. Those are the cities seen live in #526. The K5 prompt ("Call archive with an array of 200 distinct full city names...") names no cities, so any first city is legitimate. A city not in the list would raise a false drift alert.

The check now matches /^print\(default_api\.archive\(cities=\['[^'\\\n\r]*[^'\\\s][^'\\\n\r]*$/. That is the archive prefix and one unfinished city with no quote, backslash or newline, and not blank. All 63 interpreter anomalies in the 161 live captures from 2026-10-11 have exactly this shape (60 Tokyo, 3 London). None has more than one city.

Everything else is unchanged: the google:python_interpreter call name, exactly one argument, no extra call fields, the two-chunk stream position rules, the MAX_TOKENS terminal with empty text, and native leg only. A short comment at the check explains why any city is accepted and what is still enforced.

Tests

• New: Paris variants (stream and object) are accepted on the native leg and rejected on the modeled leg.
• Removed: the "unobserved first city is rejected" mutant. That behavior is intentionally gone.
• New mutants that must fail: empty city (cities=['), empty quoted city (['']), whitespace-only city ([' ), a finished call (['Tokyo'])), trailing code (['Tokyo'] + x), leading code before the call, a non-archive tool in the code (default_api.search(...)), and a different prefix (archive(names=[...). The existing mutants still fail: extra argument, extra call field, non-interpreter name, the declared archive tool, chunk placement.
• Regex mutation check: using \S for the required character (it can match the closing quote), removing either anchor, or making the city optional each fails at least one test. Removing origin === "native" fails 7 modeled-leg tests.
• Replay of all 161 live captures through the classifier: same verdict for every capture before and after the regex change, 0 rejected, 63 interpreter anomalies.

Local red/green

RED (Tokyo/London list, Paris variants):

AssertionError: contradictory-target: K5 tool or thought
Tests  2 failed | 2 passed | 108 skipped (112)

RED for the tightening (prefix-only check, new negative tests):

Tests  4 failed | 108 passed | 4 skipped (116)

GREEN (final, full drift file):

Tests  113 passed | 4 skipped (117)

Live (AIMOCK_VERTEX_LIVE=1, gemini-2.5-flash, us-central1)

Two consecutive runs on the final code, 4/4 cases run and passed each time:

• Run 1: k5-object and k5-stream approved-interpreter-anomaly; k9-object and k9-stream visible-answer-completion.
• Run 2: k5-object and k5-stream approved-interpreter-anomaly; k9-object reasoning-only-exhaustion, k9-stream visible-answer-completion.

Gates

pnpm typecheck, pnpm lint, pnpm format:check, pnpm build and pnpm test (377 files, 14079 passed) all pass.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@copilotkit/aimock@527

commit: 23d351c