Conciseness

The body states the same known concept three times — the intro paragraph ("Invalid ARIA attributes are ignored by screen readers..."), the three "Quick Reference" bullets, and the "Explain" section all restate that unsupported attributes break assistive-tech communication, which is knowledge Claude already has. This matches 'mostly efficient but includes some unnecessary explanation or could be tightened'; it is not 2 because the body is short and free of long padded tutorials.

Actionability

The Check/Fix/Code Review sections give directed guidance ("Verify that all ARIA attributes used on elements are valid for their assigned WAI-ARIA roles", "Flag exact elements, roles, labels, focus behavior, or keyboard interactions") and concrete tooling exists one hop away in references/rule.md (axe, Lighthouse, accessibility-tree inspection). It is not 4 because the body itself contains no executable example, tool name, or allowed-attribute reference — every inline instruction is a high-level directive with the key details deferred.

Workflow Clarity

The Check → Fix → Explain → Code Review section sequence is clear for a simple single-purpose skill, and verification steps (automated and manual) exist in the reference, matching 'clear sequence with most checkpoints present; minor validation gaps'. It is not 5 because no validation checkpoint appears in the body itself and the Code Review section's sentence "Review the rendered markup and interactive states that affect Use only allowed ARIA attributes for each role" is grammatically broken, slightly muddying the final step.

Progressive Disclosure

The body is a short, well-sectioned overview that clearly signals exactly one one-level-deep reference — "For full implementation details, code examples, and framework-specific guidance, see references/rule.md" — and that file exists and delivers precisely what is promised (code example, exceptions, standards, verification steps). This matches the 'clear overview with well-signaled one-level-deep references; easy navigation' anchor, and the sub-50-line guideline for simple skills also supports a 5.

Specificity

The description lists several concrete actions — "Check native semantics first, then inspect keyboard behavior, focus flow, accessible names, and screen-reader output" — which matches the 'several specific actions; minor gaps' anchor. It is not a 5 because the core capability is never stated as a clean action (the rule title is embedded mid-sentence as "related to Use only allowed ARIA attributes for each role") and "where relevant" hedges the coverage; it is above 3 because multiple genuinely specific inspection actions are named.

Completeness

Both halves are present: an explicit "Use when reviewing rendered HTML, interactive components, or design-system patterns..." when-clause and a what conveyed by the ARIA-attribute checking actions. It is not a 5 because the 'what' is not clearly stated — "related to Use only allowed ARIA attributes for each role" is a grammatically broken template substitution that muddles the capability rather than concretely naming it.

Trigger Term Quality

Keywords like "rendered HTML", "ARIA attributes", "keyboard behavior", "focus flow", "accessible names", and "screen-reader output" give good natural-term coverage, matching the 'good keyword coverage; a few natural terms missing' anchor. It falls short of 5 because common user phrasings such as "accessibility", "a11y", "WCAG", and "aria-*" are absent, and above 3 because coverage goes well beyond a single generic keyword.

Distinctiveness Conflict Risk

The rule topic itself (allowed ARIA attributes per role) is a recognizable niche, but the when-clause "reviewing rendered HTML, interactive components, or design-system patterns" is a broad template that would trigger identically for many sibling accessibility rules (e.g., other ARIA or keyboard/focus rules), so overlap with closely related skills is real. It is above 2 only because the embedded rule name and ARIA-specific terms provide some differentiation.