Conciseness

The body is compact overall, but the container-to-child role mapping is stated twice ('tablist → tab, list/listbox → listitem/option...' in Quick Reference and again in full in Check), the intro paragraph and the Explain section both cover screen-reader consequences, and the Code Review section is generic boilerplate. Mostly efficient, but the duplication could be tightened into a single mapping.

Actionability

Concrete and specific throughout: Check enumerates exact role-to-required-child requirements ('tablist must own tab elements; list must own listitem...') and Fix gives three executable remediation steps ('add role=tab to each tab button', 'add role=none/presentation to those wrappers', 'prefer <ul>/<li> instead of role=list/listitem'). For an instruction-only review skill this is largely executable; the only gaps are verification tooling specifics deferred to the reference.

Workflow Clarity

The Check → Fix → Explain → Code Review sections form a clear, unambiguous sequence with per-role verification criteria, and the task is single-purpose and non-destructive so the validation cap does not apply. Checkpoints are mostly present ('note how to verify the fix with browser accessibility tooling'), though the concrete verification steps (axe, accessibility tree) live only in the reference file.

Progressive Disclosure

The body is a proper overview and full implementation details (code examples, standards, exceptions, verification) are split into a single, existing, one-level-deep reference, clearly signaled ('For full implementation details, code examples, and framework-specific guidance, see references/rule.md'). Minor gaps: the pointer appears only at the bottom, and the role-mapping table is duplicated between SKILL.md and rule.md.

Specificity

The description names the domain thoroughly ('custom ARIA widgets using composite roles: tablist, list, listbox, menu, menubar, tree, treegrid, grid, rowgroup, row, radiogroup' and 'div/span elements that replace native HTML list, select, or nav elements') but states no concrete actions at all — there is no verb describing what the skill does. It is not entirely vague (anchor 1), but the absence of any 'what' action matches 'names the domain but actions are minimal or generic'.

Completeness

Both clauses are explicit 'Use when...' triggers ('Use when applies to custom ARIA widgets...', 'Use when reviewing components built with div/span elements...'), so 'when' is well covered. But 'what' — e.g., checking that container roles contain their required child roles — is never stated, matching the anchor 'only when is present without what'.

Trigger Term Quality

Strong keyword coverage: eleven concrete ARIA role names plus 'div/span elements' and 'native HTML list, select, or nav elements' are terms users would naturally say when reviewing such components. However, common natural synonyms like 'accessibility', 'a11y', 'screen reader', or 'WCAG' are missing, so it falls short of the comprehensive-synonyms anchor.

Distinctiveness Conflict Risk

A clear niche (ARIA composite-widget required-children) with highly specific role-name triggers makes it mostly distinct. Minor overlap risk remains with the closely related sibling rule aria-required-parent and general ARIA review skills, which would trigger on the same 'div/span custom widget' phrases.