[dev-pmallapp]

Build target 4 of docs/design/stories/293.md. Anchors CLAIM-293.6 and NEVER-293.7.

Verdict: PASS for case 8 and case 20. Case 9 is PARTIAL and CLAIM-293.6 is NOT met — half (ii) needs a transcribed skill and a runner, and case 9's own Command column names bun run skill-harness, which does not exist in this tree. It closes at #323.

Evidence: docs/evidence/320-20260908T074833Z.md

Chain at b297932

959 tests / 945 pass / 0 fail / 14 skip / 3389 expect() · lint 0 across 107 files · typecheck clean · skill-lint 4 + 12, 0 errors · claim-lint 116 files, 0 errors, 1 warning (the expected stories/9.md one).

What it ships

• Five injectable failure modes, including the third state — a 403 with no budget header, which is the common case because gh api --include appears nowhere in this repository.
• No duplicate check on any identity key. GitHub answers 422 on a duplicate milestone title and the fake deliberately does not, so run 2's silence is the skill's decision and never the double's.
• The fake imports no launcher — it answers argv from memory, which keeps CLAIM-293.1's "exactly one production module launches a process" true.

Mutation testing — 10 injected, 8 killed

The M9/M9b pair is the argument: with case 8's state-growth assertion weakened to expect(exitCode).toBe(0) and the fake made to enforce the 422, all four of case 8's tests pass. The kill comes from case 9 (ii), a different case anchored to a different claim. NEVER-293.7's own case, written the obvious way, scores the exact defect it exists to detect as a pass.

Findings raised, none fixed here

1. Case 8 asserted on an exit code cannot detect an enforcing fake.
2. Exit code and row counts collapse three of the five failure modes — only the classification separates them.
3. shouldRetryResponse answers retry: false for a transient connection error, which is the one failure references/gh-error-handling.md:120-131 tells you to retry. Needs an issue.
4. errors.ts:270's two rate-limit reasons differ only in the value they quote.
5. git clean -fd destroyed this task's uncommitted work — and the handoff recommends it as the safe alternative to rm.
6. The ## Re-entry column yields 16 keys, not the 4 the plan names; resolved as four key classes over a partition of all 16.

The first-contact bill deferred by #318 and #319 to #320 cannot be paid by a fake, and build targets 1–10 now contain no owner for it.

Refs #320