Conciseness

The body is dense with actionable guidance — variant axes, a directory template, a CSS reset, a README template, a comparison-table template, and a tool sequence — and it never explains concepts Claude already knows (no 'what HTML is', no library tutorials). A few sections could be trimmed (the duplicated GSD attribution/archival notes appear twice, and 'frontier mode' plus theming are secondary), which keeps it at 'Efficient; minor instances of over-explanation that could be trimmed' rather than a 5.

Actionability

Guidance is largely executable: exact tool-call syntax ('browser_navigate(url="file:///...")', 'browser_vision(question=...)'), a copy-paste CSS reset, a tokens.css example, concrete file layout ('NNN-stance-name/index.html + README.md'), and platform-specific open commands. It falls short of a 5 only in minor gaps: no complete sample variant HTML is provided, and the Hermes browser tools are assumed present without a fallback when they aren't — matching 'Mostly executable guidance; concrete code or commands with minor gaps'.

Workflow Clarity

The pipeline is explicit ('intake → variants → head-to-head → pick winner (or iterate)') with numbered, well-defined stages, and it includes a genuine validation feedback loop: visually verify each variant with browser_vision, 'Fix and re-navigate until each variant looks right', plus 'Open it in a browser. If it looks broken, fix it before showing the user.' This matches the top anchor — clear sequence, explicit validation steps, and an error-recovery loop; nothing in the workflow is destructive or batch, so no cap applies.

Progressive Disclosure

The skill is a single self-contained file with no bundle directories (no references/, scripts/, or assets/ exist), so all guidance is inline by design; section headers are clear and each section is scannable and independently useful. It fits 'Good structure; most content is appropriately placed; minor organization gaps' — the secondary sections (theming, frontier mode, attribution) could arguably live in reference files, and the ~220-line body exceeds the 'under 50 lines' simple-skill exception that would allow a 5 on organization alone.

Specificity

The description names its domain ("Throwaway HTML mockups") and one concrete action ("2-3 design variants to compare"), but stops there — it lists a single capability rather than several specific actions, matching the anchor 'Names domain and 1-2 concrete actions, but not comprehensive'. It is not a 4 because it does not enumerate several actions, and not a 2 because 'mockups' and 'variants to compare' are concrete, not generic.

Completeness

The 'what' is clear ("Throwaway HTML mockups: 2-3 design variants to compare") but there is no 'when' — no 'Use when...' clause or equivalent trigger guidance, which per the judging guidelines caps completeness at 3. Not a 4 because 'when' is entirely absent rather than merely imprecise; not a 2 because the 'what' half is concrete and unambiguous.

Trigger Term Quality

It includes relevant keywords ("HTML mockups", "design variants", "compare") but misses the natural phrases a user would actually say — 'sketch this screen', 'wireframe', 'prototype', 'mockup this UI' — which the body itself lists as triggers yet the description omits. This fits 'Some relevant keywords but missing common variations or synonyms'; it is above a 2 (not merely generic) but below a 4 (no natural trigger phrasing present).

Distinctiveness Conflict Risk

'Throwaway' plus '2-3 design variants to compare' carves out a clear niche — disposable comparison mockups, explicitly not production code — with mostly distinct triggers. Minor overlap risk remains with related design/prototype skills (claude-design, excalidraw-style diagramming) since the description alone doesn't state those boundaries. This fits 'Mostly distinct; minor overlap risk with closely related skills'; not a 5 because the exclusion of production/one-off design work is only stated in the body, not the description.