Conciseness

The body is dense and directive with no concept explanations ("A fixed sleep is not a readiness check"), but the generic Limitations boilerplate ("Use this skill only when the task clearly matches the scope described above", "Stop and ask for clarification if required inputs… are missing") states things Claude already knows and could be trimmed.

Actionability

The report-format block is a concrete example and the process constraints are specific, but no executable commands or example CLI invocations appear anywhere — "Capture the baseline and candidate using the actual supported CLI flags; do not invent commands" defers the core execution detail (which CLI, what flags) entirely, leaving key details missing. The non-bundled CLI partially justifies the flexibility, keeping this above the purely vague anchors.

Workflow Clarity

Clear snapshot → report → teardown sequence with explicit validation checkpoints ("wait for a deterministic ready selector and verify which revision each page actually serves", "Never promise full restoration without verifying file status and content"), but the numbered steps are compound and compressed and error-recovery guidance lives only in Gotchas rather than as explicit validate → fix → retry loops in the procedure, falling just short of the 5 anchor.

Progressive Disclosure

A 49-line body with well-organized sections (When to Use, three numbered phases, Gotchas, Limitations) and no bundle files; per the rubric's simple-skill guideline this earns a 5, and its single external pointer ("use the available `accesslint-audit` procedure") is clearly signaled and one level deep.

Specificity

Quotes multiple specific concrete actions — "Diff a live page's accessibility violations against a baseline", "compares uncommitted changes (stash-based)", "pass --branch [name] to diff against a branch", "Reports only new violations introduced, violations fixed, and pre-existing count", "Use `scan` for a full audit" — covering both diff modes, all report outputs, and the alternate full-audit command with no coverage gaps.

Completeness

The "what" is explicit and concrete, but there is no "Use when…" clause or equivalent explicit trigger guidance — the "when" is only implied by the what, which caps completeness at 3 per the judging guideline. It is not a 2 because the what is fully clear, and not a 4 because the when is absent rather than merely imprecise.

Trigger Term Quality

Good natural keyword coverage ("accessibility violations", "diff", "baseline", "audit", "branch") but common user synonyms like "a11y", "WCAG", or "accessibility regressions" are absent, so it stops short of comprehensive synonym coverage.

Distinctiveness Conflict Risk

A clear niche — accessibility violation diffing against a baseline with stash-based and branch modes — and it explicitly disambiguates from the sibling full-audit skill ("Use `scan` for a full audit with no diffing"), giving minimal conflict risk.