Conciseness

The body is lean and assumes competence: no explanation of what coverage is, compact tables for parser selection, and every rationale sentence earns its place (e.g., "a report that only scolds gets disabled", "NOISE_PP hides the sub-0.5pp jitter that test-order non-determinism produces"). Not 4: there is no trimmable over-explanation.

Actionability

Mostly executable: complete YAML for artifact restore and the sticky comment, runnable compute_diff/classify functions, and a concrete report template. Not 5: the end-to-end pipeline is not copy-paste ready — the parser is delegated to a sibling skill and coverage_diff.py's CLI/IO and report-rendering glue are shown only as invocations.

Workflow Clarity

Steps 1-7 are clearly sequenced with an explicit validation checkpoint (Step 3: "Stop and fix the inputs if any check fails") covering missing baseline, path-root mismatch, and baseline staleness, plus a verify-and-fix loop in Step 7 ("confirm exactly one coverage comment exists... if not, fix the header value or the Step 3 path check and re-run"). Not 4: validation and feedback loops are explicit, not implicit.

Progressive Disclosure

No bundle files exist, so all content lives in SKILL.md; sections are well organized with clearly signaled one-level-deep references (external tool links and sibling skills). Not 5: the ~50 lines of tunable Python in Steps 4-5 could live in a scripts/ file with the constants surfaced, which would slim the body further; not 3: structure and reference signaling are good, not buried.

Specificity

Lists multiple concrete actions — "Compares current and baseline coverage (LCOV, Cobertura or JSON)", "reports per-file line and branch deltas, new files and hidden drops, with a one-line summary for the PR comment" — with named formats and outputs, matching the comprehensive-coverage anchor. Not 4: there are no minor gaps; every capability of the skill is stated as a concrete action.

Completeness

Explicitly answers both: what ("Compares current and baseline coverage... reports per-file line and branch deltas, new files and hidden drops, with a one-line summary") and when ("Use when a pull request needs readable coverage feedback rather than one total"). Not 4: the when-clause is explicit and concrete, not merely present or vague.

Trigger Term Quality

Good natural keywords — "pull request", "coverage", "coverage feedback", "LCOV", "Cobertura", "PR comment" — but common synonyms like "code coverage", "test coverage", "coverage drop/regression" and file extensions (.info, coverage.xml) are absent. Not 5: keyword coverage is good rather than comprehensive with synonyms and extensions.

Distinctiveness Conflict Risk

The per-file delta / PR-comment-reporting niche is clearly distinct from a pass/fail coverage gate, but generic "coverage" triggers overlap with closely related sibling skills (lcov-analysis, jacoco-analysis, coverage-py-analysis). Not 5: minor overlap risk remains with these adjacent coverage skills.