Conciseness

The body is mostly dense and earned, but the five-heading shape rule and the forbidden-heading list ("`## Summary`, `## Verdict`, `## Scope and method` and `## Bottom line`") are repeated three times, the `grep -c` shape check appears twice, and rhetorical asides ("however good the audit inside it", "and that is the one way this run fails outright") pad the prose — more than the minor trimming of anchor 4, so it sits at anchor 3.

Actionability

Guidance is fully executable throughout: exact commands (`git diff --name-only "$BASE"...HEAD`, `bun run --cwd <workspace-path> test:run`, the verbatim `TEST-REVIEW.md` heredoc, the two `grep -c` checks), an exact four-field finding template, and concrete test patterns (`Effect.flip`, `createXxxRoutes(createTestLayer())`) covering the common cases — matching anchor 5 rather than the minor-gaps anchor 4.

Workflow Clarity

Steps 0–4 are clearly sequenced with explicit validation checkpoints (the shape check that "must print `5`", run "as soon as the first gap is in the file", and the two-count final check) and error-recovery loops ("No step is a stop"; restore the skeleton if a count is low) — the anchor 5 pattern of sequence plus validation plus feedback, not merely the most-checkpoints-present anchor 4.

Progressive Disclosure

Sections are well-organized with clear `##` headers and the two `wiki/conventions/` pointers are clearly signaled inline, but there is no bundle structure at all — long sub-procedures such as the credential-enumeration walkthrough and the tautological-test checklist are inlined in a ~215-line file where anchor 5 would split them into one-level-deep reference files; better than anchor 3, whose structure and signaling would be genuinely unclear.

Specificity

The description lists multiple concrete actions — "building and running the affected workspaces", "auditing changed code for missing test files, untested exports, untested error paths and untested routes", "reporting gaps with T-M/U/E/R/S IDs in the four-field format" — giving comprehensive coverage of what the skill does, matching the anchor 5 example rather than the minor-gaps anchor 4.

Completeness

It explicitly answers both questions: the "what" is building/running tests and auditing changed code for four named gap classes, and the "when" is stated as an explicit "Use when checking whether a branch is adequately tested" trigger — clearly above anchor 4, where the "when" would be less explicit.

Trigger Term Quality

"checking whether a branch is adequately tested" is a phrase a user would naturally say, and "branch", "tested", "workspaces" are relevant terms, but common synonyms such as "test coverage", "missing tests", or "unit tests" are absent — good keyword coverage with a few natural terms missing, above anchor 3 but short of the comprehensive synonym coverage of anchor 5.

Distinctiveness Conflict Risk

The description carves a clear niche — a branch-level test audit producing a report with a named T-M/U/E/R/S taxonomy in a four-field format — which is unmistakable against generic run-the-tests or code-review skills; not anchor 4, since even minor overlap risk is suppressed by the distinctive output contract.