Conciseness

The body is short and mostly lean, but the opening paragraph ("The browser's HTML parser discovers resources sequentially — a font referenced in a CSS file won't be fetched until the CSS is parsed... 100–300ms Flash of Invisible Text") explains a concept Claude already knows and is duplicated verbatim in references/rule.md's "Why It Matters". That is a trimmable instance of over-explanation, but not the padded multi-section verbosity of a 3.

Actionability

Guidance stays high-level: "Add appropriate preload hints for critical fonts, images, and scripts. Add preconnect for third-party domains used early in the page" names the actions but omits key executable details (no example markup like `<link rel="preload" href="/fonts/inter.woff2" as="font" type="font/woff2" crossorigin>`, no mention of the required `as`/`crossorigin` attributes) — those live only in the reference. This fits "some concrete guidance but incomplete" rather than the mostly-executable profile of a 4.

Workflow Clarity

The Check → Fix → Explain → Code Review sections give a recognizable sequence, but there are no validation/verification checkpoints in the body — how to confirm a hint is correct (e.g., checking for double-fetched fonts or missing `as` attributes) is deferred entirely to the reference. Sequence present with checkpoints missing matches anchor 3, not 4.

Progressive Disclosure

Clean structure: a concise overview body with well-signaled, one-level-deep pointer — "For full implementation details, code examples, and framework-specific guidance, see `references/rule.md`" — and references/rule.md exists and delivers exactly what is promised (code examples, framework guidance, verification). No nesting or buried references, matching the clear-overview anchor.

Specificity

The description lists several concrete actions — "reviewing templates, rendered HTML, or shared components" and "Validate the final browser-facing markup" — anchored to a specific domain (resource hints). Coverage has minor gaps (e.g., fixing/adding hints is only implied via the rule name), so it sits between the 1-2-action anchor (3) and comprehensive coverage (5).

Completeness

Both parts are explicit: the "what" is "Validate the final browser-facing markup, not just the source framework abstraction" and the "when" opens with a concrete trigger phrase — "Use when reviewing templates, rendered HTML, or shared components related to...". This matches the anchor that clearly answers both what and when with concrete trigger phrases; it does not fall to 4 since the when-clause is explicit rather than merely adequate.

Trigger Term Quality

Good natural keyword coverage: "templates", "rendered HTML", "shared components", "preload, prefetch, dns-prefetch", "markup" — terms a user reviewing HTML would plausibly say. A few natural variants are missing ("preconnect", "font loading", "HTML performance"), keeping it below the comprehensive-synonyms anchor (5) but clearly above sparse keyword coverage (3).

Distinctiveness Conflict Risk

The resource-hint niche (preload/prefetch/dns-prefetch in rendered HTML) is distinct with its own trigger terms, but it could overlap with adjacent HTML-performance or general HTML-review skills, so minor overlap risk remains rather than the minimal-conflict profile of a 5.