Conciseness

The ~30-line body is lean with no padding or explanation of concepts Claude already knows — "Treat accessibility as behavior to implement and verify, not a label-only cleanup" earns its place as a framing principle, and every rule is a terse directive. Matches anchor 5 (lean, assumes competence, every token earns its place); anchor 4's 'minor instances of over-explanation' does not apply.

Actionability

Concrete directives like "Prefer semantic built-in controls before manually adding `Semantics`" and "Use widget tests with semantics enabled and Flutter's accessibility guideline matchers" give mostly executable guidance, and as an instruction-only skill the absence of code is not penalized. Not a 5 because specifics a user would need to execute — named matchers, test commands, concrete threshold numbers — are deferred to references and "where suitable" hedges the verification advice.

Workflow Clarity

A clear audit → apply rules → verify arc: "Audit the flow" lists what to identify, Rules state what to enforce, and Verification specifies widget tests plus "TalkBack or VoiceOver and keyboard navigation". Matches anchor 4 (clear sequence with most checkpoints present); not a 5 because verification is not woven in as an explicit validate-and-fix loop, and not a 3 because a concrete verification section is present.

Progressive Disclosure

The body is a concise overview with two one-level-deep references, each clearly signal-conditioned: "Read [semantics and screen readers](references/semantics-and-screen-readers.md) when annotating custom widgets..." and "Read [target sizes and contrast](references/target-sizes-and-contrast.md) when auditing WCAG AA contrast ratios...". Both referenced files exist in the bundle with real content, and nothing that belongs in a reference is inlined — matches anchor 5.

Specificity

"Build or audit Flutter accessibility for semantics, screen readers, focus, keyboard access, text scaling, contrast, target size, and motion preferences" names two concrete actions (build, audit) and enumerates eight specific capability areas. Not a 5 because the action verbs are limited to build/audit while the anchor-5 example shows multiple distinct concrete actions; not a 3 because coverage of the domain is far more comprehensive than 1-2 actions.

Completeness

The "what" is clear ("Build or audit Flutter accessibility for semantics, screen readers, focus..."), but the only when-clause — "Pair with flutter-responsive-layout when large text causes reflow" — governs pairing with another skill, not when to use this skill. Per the guideline that a missing 'Use when...' clause for the skill itself caps completeness at 3, this fits anchor 3 (clear what, when missing or only weakly implied) rather than anchor 4.

Trigger Term Quality

Includes natural terms users would say such as "accessibility", "screen readers", "contrast", "text scaling", "keyboard access", and "target size". Missing common synonyms and tool names like "a11y", "VoiceOver", "TalkBack", or "WCAG" that anchor 5 expects, but coverage is clearly better than anchor 3's partial keyword set.

Distinctiveness Conflict Risk

"Flutter accessibility" plus specific areas (semantics, screen readers, target size, motion preferences) carves a clear niche with minimal overlap risk, and the pairing note "Pair with flutter-responsive-layout when large text causes reflow" explicitly resolves the boundary with the closest neighboring skill. This matches anchor 5's clear-niche example and is well above anchor 4's minor-overlap case.