Conciseness

The ~20-line body is lean with zero padding or explanations of concepts Claude already knows — every line is environment-specific instruction ("check `git status` first", "Report meaningful findings during the run with `update_user` on `voice_agent`") — matching anchor 5 (every token earns its place); anchor 4 would require some trimmable over-explanation, which is absent.

Actionability

Guidance is fully concrete for an instruction-only skill: named files (`AGENTS.md`, `CLAUDE.md`, `CONTRIBUTING.md`, `README.md`), a specific command (`git status`), quoted user trigger phrases ("Why is this failing", "figure out", "look into", "review", "explain"), and named tools (`github__*` on `voice_agent`, `request_permission`) — matching anchor 5's 'specific examples cover the common cases' with no minor gaps that would justify a 4.

Workflow Clarity

A clear sequence is present with explicit ordering cues ("check `git status` first", "Reproduce first with a failing test or command", "when the turn ends") and validation checkpoints ("Run existing tests, linters, and type checkers, and report only checks you actually ran"), but no explicit error-recovery feedback loop (e.g., 'if the test still fails, fix and re-run') is spelled out, matching anchor 4 rather than anchor 5.

Progressive Disclosure

The skill is under 50 lines with no external references needed, and the content is well-organized into clearly labeled sections (Diagnose without changing, Fixing, Verifying, Git & GitHub, Finishing); per the simple-skill guideline, this merits anchor 5 — no bundle files exist, so nothing is inlined that belongs elsewhere.

Specificity

The trigger clause lists several concrete actions — "diagnoses, fixes, changes, reviews, or tests code" — but the opening 'what' ("How to work in a code repository under ~/code") is generic and capabilities like git/PR handling are absent, matching anchor 4 (several specific actions, minor gaps) rather than anchor 5's comprehensive coverage.

Completeness

Both parts are explicitly answered: the what ("How to work in a code repository under ~/code" plus the five enumerated actions) and an explicit when with concrete trigger phrases ("Use for any thread that diagnoses, fixes, changes, reviews, or tests code"), matching the anchor-5 example structure; anchor 4 does not fit because the 'when' is already fully explicit.

Trigger Term Quality

"diagnoses, fixes, changes, reviews, or tests code" gives good coverage of natural user verbs, matching anchor 4; it falls short of anchor 5 because common synonyms users say ("debug", "bug", "refactor", "build", "error") are missing, but it is well above anchor 3's single-phrase coverage.

Distinctiveness Conflict Risk

The ~/code location scoping adds some distinctiveness, but the trigger "Use for any thread that... reviews, or tests code" is broad and would fire alongside dedicated code-review, debugging, or testing skills in a crowded category, matching anchor 3 (somewhat specific but could still overlap with similar skills) rather than anchor 4's 'minor overlap risk'.