Conciseness

The body is lean and mostly earns its tokens: "Use <th> elements for headers with scope='col' or scope='row'", "Use id/headers for complex tables with merged cells" are tight and directive. Minor trimming opportunities keep it below 5: the opening concept explanation ("Screen readers read table data cell-by-cell—without proper headers, users hear meaningless numbers") tells Claude something it already knows, and the Check/Fix/Explain sections restate the same guidance three ways ("Add proper table headers with scope attributes, captions for context…").

Actionability

For an instruction-only skill the guidance is largely actionable: the Quick Reference names exact elements and attributes (th + scope='col'/'row', caption, id/headers for merged cells, CSS Grid/Flexbox over layout tables) and even reviewer prioritization ("Prefer one strong table-semantics finding over multiple weaker enhancements"). Not a 5 because some directives stay abstract ("ensure tables are not used for layout", "Check native semantics first, then inspect keyboard behavior…" — the Code Review section is generic template text rather than table-specific), and executable markup examples are deferred entirely to the reference file.

Workflow Clarity

The Check → Fix → Explain → Code Review sections give a clear, ordered review workflow, and verification is addressed ("note how to verify the fix with browser accessibility tooling or assistive tech"), with concrete automated/manual checks one level deep in references/rule.md. Not a 5 because the inline verification pointer is implicit rather than an explicit checkpoint — the actual validation steps (axe/Lighthouse, NVDA table navigation) live only in the reference file.

Progressive Disclosure

The ~35-line body is a genuine overview: a tight Quick Reference with the essentials, and a clearly signaled one-level-deep pointer — "For full implementation details, code examples, and framework-specific guidance, see references/rule.md" — which is a real file containing exactly that (code examples, scope attribute table, React component, verification steps). Content is appropriately split with no nested references and easy navigation.

Specificity

Concrete actions are listed ("Check native semantics first", "inspect keyboard behavior, focus flow, accessible names, and screen-reader output"), but they are generic review-template actions — none are specific to table semantics (no th, scope, caption, or headers attributes), so coverage of the actual skill has more than minor gaps. Fits the 3 anchor (domain named, concrete actions present, not comprehensive) better than 4, whose "minor gaps" these are not.

Completeness

Both parts are explicitly present: the "what" via "Check native semantics first, then inspect keyboard behavior, focus flow, accessible names, and screen-reader output" and the "when" via "Use when reviewing rendered HTML, interactive components, or design-system patterns related to…" — so it clears the missing-'Use when' cap. Not a 5 because the "what" is generic boilerplate not tied to table markup, and the "when" clause is broad/templated rather than a concrete table-specific trigger.

Trigger Term Quality

Good natural keyword coverage: "semantic table markup", "screen readers", "rendered HTML", "interactive components", "keyboard", "focus" — phrases a user would plausibly say. A few natural terms are missing ("accessibility", "a11y", "table headers", "scope/caption"), and the templated embedding "related to Use semantic table markup" reads awkwardly, keeping it below the 5 anchor's comprehensive synonym coverage.

Distinctiveness Conflict Risk

"semantic table markup for screen readers" carves out a niche, but the trigger surface "rendered HTML, interactive components, or design-system patterns" is broad, and the action list ("keyboard behavior, focus flow, accessible names") overlaps heavily with sibling accessibility skills that would share this identical template text. Matches the 3 anchor (somewhat specific but still overlaps with similar skills) rather than 4's "minor overlap risk only with closely related skills".