Conciseness

The operational core (Quick Reference, Check, Fix) is tight and instruction-dense, but the opening paragraph and the 'Explain' section both restate WCAG 1.1.1 / screen-reader basics Claude already knows, duplicating each other and references/rule.md's 'Why It Matters'. Matches anchor 3 (mostly efficient, some unnecessary explanation) rather than 4 (two full sections of known-concept explanation is beyond minor trimming) or 2 (the majority of the body is not padding).

Actionability

Check enumerates five concrete verification criteria plus specific flag conditions ('alt matching the filename (e.g., alt="photo1.jpg")', 'generic values like alt="image"'), and Fix gives per-case remediation with before/after example alt text and aria-describedby for complex images. Not 5 because 'Scan all <img> elements in the codebase' lacks an executable command; not 3 because the guidance is specific and example-backed well beyond high-level hints.

Workflow Clarity

The Check → Fix → Explain → Code Review sections form a clearly labeled sequence in execution order, with a verification checkpoint present ('describe how to confirm the fix in DevTools'). Not 5 because there is no explicit re-validation loop after applying fixes; not 3 because the sequence is unambiguous and a DevTools confirmation step is stated.

Progressive Disclosure

The ~35-line body is a well-organized overview with a single clearly signaled, one-level-deep pointer to references/rule.md ('For full implementation details, code examples, and framework-specific guidance, see references/rule.md'), which exists and contains exactly that without further nested file references. Matches anchor 5 and the simple-skill exception for well-organized short skills.

Specificity

Explicit concrete actions are enumerated — 'reviewing image assets, markup, and CDN or build transforms' and 'Check encoded size, rendered size, loading strategy, and above-the-fold impact' — with only a minor gap: the alt-text action itself is never stated as a verb, only embedded via the phrase 'related to Provide meaningful alt text for images'. Matches anchor 4 (several specific actions, minor gaps) rather than 5 (capability coverage is not comprehensive) or 3 (more than 1-2 minimal actions are listed).

Completeness

Both are explicitly answered: 'when' via the clause 'Use when reviewing image assets, markup, and CDN or build transforms' and 'what' via 'Check encoded size, rendered size, loading strategy, and above-the-fold impact together'. Not 5 because the capability statement is tangled into the trigger sentence and the awkward embedded phrase 'related to Provide meaningful alt text for images' blurs the what; not 3 because both what and when are explicitly present.

Trigger Term Quality

Natural trigger terms are present — 'alt text', 'image assets', 'markup', 'loading strategy', 'above-the-fold' — but common variations a user would say ('accessibility', 'screen reader', 'WCAG', 'a11y') are missing. Matches anchor 4 (good coverage, a few natural terms missing) rather than 5 (no synonym/extension coverage) or 3 (the core natural phrase 'alt text for images' is explicitly present).

Distinctiveness Conflict Risk

The alt-text niche itself is distinct, but 'Check encoded size, rendered size, loading strategy, and above-the-fold impact together' is the exact territory of sibling image-optimization rules (formats, responsive images, lazy loading), so the description would trigger on image-delivery questions that are not about alt text. Matches anchor 3 (somewhat specific but could still overlap with similar skills) rather than 4 (the overlap risk is more than minor).