Conciseness

The body is a lean, checklist-style rule set with concrete thresholds ('4.5:1 minimum', '44x44px', 'clamp(1rem, 2.5vw, 2rem)') that assumes Claude's competence and avoids explaining basics. Minor duplication keeps it below the level-5 anchor: focus-trap/return-focus appears in both A11Y-03 and CP-05, and aria-busy appears in both A11Y-05 and CP-02.

Actionability

Rules are concrete and checkable ('Icon-only buttons MUST have aria-label', 'Use min-height: 100dvh (not 100vh)') with a fully specified output format and a worked example ('src/Button.tsx:12 — [A11Y-01] Missing aria-label on icon button'). It stops short of the level-5 anchor because there are no bad→good code examples illustrating typical violations and fixes.

Workflow Clarity

The Review Checklist provides an explicit prioritized audit sequence ('check in this order (CRITICAL first): 1. CRITICAL: A11Y-01, A11Y-02, SEC-01...') plus a defined report format, giving a clear sequence for the audit workflow. It lacks a final verification pass over reported findings, so it matches the level-4 anchor rather than the explicit-validation level-5 anchor; the destructive/batch cap does not apply since this is a read-only audit.

Progressive Disclosure

The document is well-organized with stable rule IDs, clear sections, and a prioritized checklist, and it is appropriately self-contained with no bundle files. At ~190 lines it exceeds the under-50-line single-file exception, and per-category detail could be split into one-level-deep reference files, placing it at the 'good structure; minor organization gaps' anchor rather than level 5.

Specificity

The description names the domain ('Review UI code for Web Interface Guidelines compliance') and one concrete action — reviewing/auditing — which matches the anchor for naming a domain with 1-2 concrete actions. It does not list several specific actions (accessibility, performance, responsive checks are only implied through trigger quotes), so it falls short of the level-4 anchor.

Completeness

It explicitly answers both 'what' ('Review UI code for Web Interface Guidelines compliance') and 'when' ('Use when asked to...') with concrete quoted trigger phrases, matching the level-5 anchor exactly. The 'when' clause is explicit and specific, so it clearly exceeds the level-4 anchor where 'when' could be more explicit.

Trigger Term Quality

Quoted phrases like "review my UI", "check accessibility", "audit design", "review UX", and "check my site against best practices" are natural user phrasings with good coverage. A few common terms are missing (e.g., 'a11y', 'WCAG', 'front-end review', 'heuristic evaluation'), so it does not reach the comprehensive level-5 anchor.

Distinctiveness Conflict Risk

The 'Web Interface Guidelines' niche is distinct with dedicated trigger phrases. 'check accessibility' and 'audit design' could still overlap with a dedicated accessibility or design-system skill, matching the 'mostly distinct; minor overlap risk' anchor rather than the minimal-conflict level-5 anchor.