Conciseness

The body is dense, checklist-driven, and free of padded prose or library comparisons, but the ~45-line four-principles section restates WCAG criteria Claude already knows and substantially duplicates references/wcag-quick-reference.md (e.g., the inline alt-text checks mirror the reference's 1.1.1 checks almost verbatim). That duplication is a minor token cost, not the noticeable verbosity of the 3 anchor.

Actionability

Guidance is highly concrete — named tools (axe DevTools, Lighthouse, WAVE, Pa11y), exact keyboard interactions (Tab/Shift+Tab, Enter, Space, Escape), exact ratios (4.5:1, 3:1), and exact values (200% zoom, 320px reflow) — meeting the mostly-executable 4 anchor. It misses 5 because commands are not copy-paste ready: Pa11y is a CLI with no invocation given, and "use a contrast checker" names no specific tool.

Workflow Clarity

The 10-step workflow is clearly sequenced with per-stage test checklists, a severity rubric, and a data-availability rule ("state the gap per the data-availability rule") acting as a checkpoint. It stays at 4 rather than 5 because there is no verification or feedback loop after remediation — no step to re-scan or re-test to confirm fixes — and step 7's scoring step has no explicit checkpoint; the audit is read-only, so the destructive/batch cap at 3 does not apply.

Progressive Disclosure

Structure is good: three real, one-level-deep reference files (verified present in references/), clearly signaled both inline at workflow step 9 and in a dedicated Reference files section with content descriptions, and aria-patterns.md explicitly expands the inline checks. It misses 5 because the inline four-principles checklist overlaps the quick-reference file's stated purpose ("Condensed WCAG 2.1 AA criteria with audit checks"), so some criterion-level content that should live only in the reference is duplicated inline.

Specificity

"Run a comprehensive WCAG accessibility audit covering perceivable, operable, understandable, and robust principles" names the domain plus the audit action with an enumerated four-principle scope, and the trigger list implies several more actions (review WCAG compliance, fix accessibility issues, prepare for certification). It falls short of the 5 anchor because the concrete deliverables (audit report, remediation plan) are not stated, and above 3 because it lists more than 1-2 specific actions with broad coverage.

Completeness

Both parts are explicit: the what ("Run a comprehensive WCAG accessibility audit covering perceivable, operable, understandable, and robust principles") and the when ("Use this skill whenever the user wants to audit accessibility, review WCAG compliance, fix accessibility issues, prepare for accessibility certification, address an accessibility lawsuit risk, or systematically improve a site's accessibility"). This matches the anchor-5 pattern of what plus a concrete 'Use when...' trigger clause, so 4 (when could be more explicit) clearly does not fit.

Trigger Term Quality

The explicit trigger list covers ten natural phrases including synonyms users actually say: "accessibility audit, WCAG audit, a11y audit, accessibility compliance, ADA compliance, screen reader test, keyboard navigation, accessibility report, fix accessibility, axe scan" — jargon synonyms (a11y, ADA) and a tool name (axe) are all present. Only marginal terms like "Section 508" or "make my site accessible" are absent, which does not drop it below comprehensive coverage.

Distinctiveness Conflict Risk

The niche is unambiguous — WCAG/accessibility auditing — and the trigger terms (a11y, WCAG, ADA, screen reader, axe) point squarely at this skill rather than generic QA or design skills. Only borderline terms like "keyboard navigation" could plausibly reach a frontend skill, which is minimal conflict risk fitting the 5 anchor.