Conciseness

The body is a lean rule catalog: terse directives ("modals must trap focus while open", "do not use tabindex greater than 0") and compact before/after snippets with no filler or concept explanations, so it is well above anchor 3. It is not a 5 because a portion of the quick-reference rules restate standard WCAG knowledge Claude already has (e.g., "links must have meaningful text", "images must have correct alt text"), which could be trimmed without loss.

Actionability

Concrete, code-level guidance is present: a priority table, exact attributes to apply (aria-describedby, aria-invalid, aria-expanded), and executable before/after HTML in the "common fixes" block, plus an explicit review output format (quote the snippet, state the failure, propose a small fix). Not a 5 because the fix examples use ellipsis placeholders ("<svg>...</svg>") rather than fully copy-paste-ready code, and complex-widget guidance defers to "established accessible primitives" without naming any.

Workflow Clarity

As a simple single-purpose instruction skill, both usage modes are unambiguous: constraint mode ("Apply these constraints to any UI work") and file-review mode with an explicit report structure (violations with quoted lines, why it matters, a concrete fix) plus priority ordering ("fix critical issues first (names, keyboard, focus, tool boundaries)") and a scoped-change rule ("Do not rewrite large parts of the UI"). No destructive or batch operations exist, so no validation checkpoints are required; the single action is unambiguous, meeting the simple-skill exception.

Progressive Disclosure

Structure is good: a priority table up front, nine clearly headed rule categories ordered by priority, a common-fixes example block, and a closing review-guidance section, with no external bundle files present or needed. Not a 5 because the body exceeds the under-50-lines simple-skill threshold, and the nine-category rule catalog (~90 lines of rules) could arguably be split into a reference file to keep SKILL.md a leaner overview; still clearly above anchor 3 since everything present is well-signaled and navigable.

Specificity

"Audit and fix HTML accessibility issues including ARIA labels, keyboard navigation, focus management, color contrast, and form errors" lists multiple specific concrete actions (audit, fix) with comprehensive enumeration of the domain's capability areas (ARIA, keyboard, focus, contrast, form errors), matching the anchor-5 example's coverage pattern. It is not a 4 because coverage is comprehensive rather than having minor gaps, and not below since every named capability is concrete rather than generic.

Completeness

The "what" is explicit ("Audit and fix HTML accessibility issues including ARIA labels, keyboard navigation, focus management, color contrast, and form errors") and the "when" is explicit with concrete trigger phrases ("Use when adding interactive controls, forms, dialogs, or reviewing WCAG compliance"), directly matching the anchor-5 example structure. Not a 4 because the when-clause is specific and trigger-phrased rather than merely adequate.

Trigger Term Quality

Natural user phrases like "ARIA labels", "keyboard navigation", "color contrast", "dialogs", "forms", and "WCAG compliance" give good keyword coverage across the domain. A few natural terms users commonly say are missing (e.g., "a11y", "screen readers"), which fits anchor 4 rather than the comprehensive synonym coverage of anchor 5; it is clearly above anchor 3 because most common phrasings are present.

Distinctiveness Conflict Risk

Accessibility auditing/fixing is a clear niche with distinct triggers (ARIA, WCAG, keyboard navigation, focus management) that virtually no other skill would claim, matching "clear niche with distinct triggers; minimal conflict risk". Not a 4 because overlap with related skills (e.g., general frontend work) is negligible given the WCAG/ARIA-specific trigger vocabulary.