Conciseness

The body is dense and table-driven with compact, load-bearing code (no padded prose), but the 31-pattern catalog partially duplicates the 'first rule of ARIA' native-fallback table, and the failures/anti-patterns tables restate knowledge Claude already has (e.g. positive 'tabindex="3"' is fragile, 'aria-hidden' on a focusable element is broken). Matches the score-4 anchor (efficient, minor instances of over-explanation that could be trimmed) rather than score 5.

Actionability

Copy-paste-ready HTML for Combobox, Tabs, Disclosure, and Tooltip, each paired with a required-ARIA/keyboard-behavior table, plus concrete failure→fix and anti-pattern→fix pairs covering the common cases. Fully executable and specific, matching the score-5 anchor rather than score 4 (no significant gaps in the guidance given).

Workflow Clarity

A coherent implicit sequence is present — prefer native HTML ('When the visual design demands a custom widget, follow the matching APG pattern exactly'), apply the per-pattern essentials, then check the 'Common ARIA failures' and 'Anti-patterns' tables — but no explicit validation checkpoint (e.g. a review checklist step) for verifying an authored widget. Matches the score-4 anchor (clear sequence, most checkpoints present, minor gaps), not score 5.

Progressive Disclosure

The skill is well-sectioned with clear headers, but there are no bundle files at all: the 31-pattern catalog, per-pattern code, the ARIA states reference, and the failure tables are all inlined in a ~240-line SKILL.md. This matches the score-3 anchor (good structure, but content that should be separate — the per-pattern essentials — is inline) rather than score 4, which requires well-signaled one-level-deep references into actual bundle files.

Specificity

Enumerates multiple concrete capabilities — 'covers the 31 canonical interactive-widget patterns (Combobox, Dialog, Menu, Tabs, Tree, etc.)', 'their required ARIA roles and states', 'the keyboard-interaction model per pattern', and 'the canonical-violations to watch for' — comprehensive and specific rather than vague. This matches the score-5 anchor (multiple specific concrete actions, comprehensive coverage) and not score 4, since there are no coverage gaps in describing what the skill provides.

Completeness

Explicitly answers both 'what' (covers the 31 patterns, required ARIA roles and states, keyboard-interaction model, canonical violations) and 'when' with concrete trigger phrases ('Use when authoring a custom interactive widget that doesn't have a native HTML equivalent, or when reviewing one for ARIA correctness'). Matches the score-5 anchor exactly; not score 4 because the 'when' clause is already explicit and specific.

Trigger Term Quality

Good natural keyword coverage — 'authoring a custom interactive widget', 'reviewing one for ARIA correctness', and concrete pattern names (Combobox, Dialog, Menu, Tabs, Tree) users would say — but common synonyms like 'accessibility', 'a11y', 'screen reader', or 'WAI-ARIA' are absent. Matches the score-4 anchor (good coverage, a few natural terms missing) rather than score 5, which requires synonym-level coverage.

Distinctiveness Conflict Risk

Clear niche — the W3C APG patterns for custom widgets — with distinct triggers; the 'doesn't have a native HTML equivalent' qualifier scopes it away from generic accessibility-audit or contrast-checking skills. Minimal conflict risk, matching the score-5 anchor rather than score 4's 'minor overlap risk with closely related skills'.