Conciseness

The body is mostly dense and useful, but the 'Core Concepts' section restates things Claude already knows ('POUR Principles', 'Accessibility Tree', 'Semantic Mapping: using native elements over generic containers'), and target-size/focus guidance is repeated across Step 3, Anti-Patterns, and the Best Practices Checklist. Not 4 because these are more than minor instances of over-explanation; not 2 because the code examples and mapping table are lean and earn their place.

Actionability

Concrete, executable code for all three platforms (HTML search form, SwiftUI button, Compose switch) plus a cross-platform API mapping table with real method names and specific WCAG values (4.5:1, 24x24px, SC numbers). Not 5 because the 'How It Works' steps are advisory directives ('Ensure...', 'Use consistent navigation patterns') without code or commands for the audit path (no axe/screen-reader testing commands).

Workflow Clarity

The five-step POUR sequence (Identify Role → Perceivable → Operable → Understandable → Robust) is clearly ordered, but there are no validation checkpoints or verification steps — nothing tells Claude how to confirm compliance (e.g., automated scanning or screen-reader testing), and the closing checklist is a static list rather than a validate-fix-retry loop. Not 4 because checkpoints are absent rather than merely minor gaps.

Progressive Disclosure

No bundle files exist, and the single body is well-organized with clear section headers, a compact ~135-line overview, and a one-level-deep References section of external links. Not 5 because the per-platform mapping tables and full example sets are the kind of content that would ordinarily split into reference files, keeping SKILL.md a leaner overview.

Specificity

The description lists multiple concrete actions — 'Design, implement, and audit accessible UI to WCAG 2.2 Level AA' — and enumerates specific capabilities ('semantic ARIA roles and labels, accessibility traits and hints, focus management, contrast, target size, and screen-reader support'), giving comprehensive coverage across Web, iOS, and Android. Not 4 because there are no minor coverage gaps; the capability list is exhaustive for the domain.

Completeness

It explicitly answers both what ('Design, implement, and audit accessible UI to WCAG 2.2 Level AA across Web, iOS, and Android...') and when ('Use when building or auditing UI for accessibility compliance, keyboard navigation, or screen-reader support') with concrete trigger phrases. Not 4 because the 'when' clause is fully explicit, not merely present.

Trigger Term Quality

Natural trigger phrases like 'accessibility compliance', 'keyboard navigation', and 'screen-reader support' appear, alongside 'auditing UI' and 'WCAG'. Not 5 because common synonyms users actually say are missing — 'a11y', 'accessibility issues', 'contrast', 'Section 508', or 'aria' as a standalone keyword.

Distinctiveness Conflict Risk

The accessibility/WCAG niche is clear and mostly distinct from sibling skills, but 'Use when building... UI' is broad enough to overlap with general frontend/design skills (e.g., frontend-patterns, design-system) that the body itself lists as related. Not 5 because of this overlap risk; not 3 because the accessibility-specific triggers (WCAG, screen readers, keyboard navigation) are strongly distinguishing.