Conciseness

The body is lean and sectioned with almost every token earning its place; only minor trimming candidates remain — the background sentence about 980px desktop-width rendering restates knowledge Claude already has, and the bullet 'Essential for mobile-responsive layouts' adds little. Matches anchor 4 ('Efficient; minor instances of over-explanation that could be trimmed') rather than 5.

Actionability

Provides a copy-paste-ready canonical snippet ('<meta name="viewport" content="width=device-width, initial-scale=1.0">'), an explicit anti-pattern rule ('Never use maximum-scale=1 or user-scalable=no'), and a concrete fix location ('in the head section'). Minor gap: the Check step says only 'a proper viewport meta tag' without enumerating the failure conditions inline. Matches anchor 4 ('Mostly executable guidance... with minor gaps') rather than 5.

Workflow Clarity

Clear, logical Check → Fix → Explain → Code Review structure for a simple single-purpose skill well under 50 lines; the single action is unambiguous and no destructive/batch operation exists to require validation checkpoints. Per the rubric's simple-skill scoring note, this matches anchor 5 ('single action is unambiguous').

Progressive Disclosure

A short overview body with a well-signaled, one-level-deep pointer ('For full implementation details, code examples, and framework-specific guidance, see references/rule.md') to a bundle file that exists and appropriately holds the framework examples, property table, and verification tools. Matches anchor 5 ('Clear overview with well-signaled one-level-deep references; content appropriately split').

Specificity

Names the domain (viewport meta tag, rendered HTML markup) and two concrete actions ('reviewing templates, rendered HTML, or shared components', 'Validate the final browser-facing markup'), but coverage is not comprehensive — it never states what specifically is checked (tag presence, values, zoom-disabling attributes). This matches anchor 3 ('Names domain and 1-2 concrete actions, but not comprehensive') rather than 4, which requires several specific listed actions.

Completeness

Both parts are present: an explicit 'Use when reviewing templates, rendered HTML, or shared components...' trigger clause, and a 'what' ('Validate the final browser-facing markup, not just the source framework abstraction'). However, the actual check (viewport tag presence and correct values) is only implied through the awkwardly embedded title phrase 'related to Set the responsive viewport meta tag', so the 'what' could be more explicit — matching anchor 4 rather than 5.

Trigger Term Quality

Includes relevant natural terms — 'templates', 'rendered HTML', 'shared components', 'viewport meta tag', 'responsive', 'markup' — but misses common variations users would naturally say, most notably 'mobile' (the core motivation for this rule), 'responsive design', and 'meta tag' phrasing distinct from the embedded title. Falls between anchors 3 and 4 but sits noticeably below the midpoint because the key 'mobile' keyword is absent.

Distinctiveness Conflict Risk

The opening 'reviewing templates, rendered HTML, or shared components' is broad and overlaps with generic HTML-review skills, but the rule-specific anchor ('related to Set the responsive viewport meta tag') carves a clear niche with minimal conflict risk among closely related skills. This matches anchor 4 ('Mostly distinct; minor overlap risk with closely related skills') rather than 3, since it is anchored to one specific rule.