Conciseness

The ~45-line body is lean with no padding and no explanation of concepts Claude already knows; every line is directive ("Read every `*.test.ts` file under `src/`", "Check the open issues first"). The single framing sentence ("A test that can't fail is worse than no test") earns its place by defining the skill's purpose, matching the score-5 anchor.

Actionability

Guidance is fully executable for an instruction-only skill: specific defect patterns ("comparing a value with itself", "`it.skip`, `describe.skip`, `it.todo`"), a concrete issue title template ("`Tests: <test name> can't catch a broken <behaviour>`"), a required body contents list, a real verification command ("`npm run check` passes"), and a concrete confirmation procedure (try a small breaking change, check the test still passes, undo it). No pseudocode or vague direction remains.

Workflow Clarity

The sequence is clear and includes explicit validation checkpoints despite being a batch operation: read every test, classify against four named patterns, confirm suspects via a break-and-revert feedback loop, dedupe against open issues ("Check the open issues first"), then file per the template, with "Nothing found is a fine result" covering the empty case. The mutation-based confirmation is exactly the feedback loop the score-5 anchor rewards, so the batch-operation cap does not apply.

Progressive Disclosure

The skill is under 50 lines with no external material needed (no references/, scripts/, or assets/ exist in the bundle), and it is organized into four well-labeled sections (Staying safe, What to look for, What to file). Per the rubric's simple-skill guideline, this earns a 5 with well-organized sections alone.

Specificity

The description enumerates the skill's complete action surface in concrete terms: "Find weak, dead or misleading tests", "file a GitHub issue for each one worth repairing", and the boundary "Files issues only; never changes code or tests". This matches the score-5 anchor of multiple specific concrete actions with comprehensive coverage; it exceeds the score-4 anchor because nothing the skill does is left undescribed.

Completeness

Both questions are answered explicitly: what ("Find weak, dead or misleading tests ... and file a GitHub issue for each one worth repairing") and when ("Use when running the test health maintenance loop, or when asked whether the tests actually check what they claim to"). The 'when' clause contains two concrete trigger phrases, matching the score-5 anchor exactly; score 4 would require the 'when' to be less explicit than it is.

Trigger Term Quality

Natural phrases users would say are present — "test health maintenance loop", "whether the tests actually check what they claim to", "weak, dead or misleading tests" — giving good keyword coverage. It falls short of the score-5 anchor because common synonyms like "flaky tests", "useless tests", "tautological tests", or "test smells" are missing, though it is clearly above the score-3 anchor's partial coverage.

Distinctiveness Conflict Risk

The niche is clear — auditing test quality and filing issues, with "never changes code or tests" separating it from test-writing and code-fixing skills. It sits at score 4 rather than 5 because test-related triggers ("weak tests") have minor overlap risk with closely related review or testing skills, but it is well above the score-3 anchor's generic overlap.