Conciseness

The 16 principles themselves are lean (1-3 sentences each with exact values), but the same content is restated three times: as Core Principles, again as the Common Mistakes table ("Same border radius on parent and child | Calculate outerRadius = innerRadius + padding"), and again as the Review Checklist. The four reference files are also listed twice (Quick Reference table plus Reference Files section). This matches the 3 anchor ('mostly efficient but could be tightened') rather than 2, since nothing explains concepts Claude already knows.

Actionability

Guidance is copy-paste concrete throughout: exact values ("~100ms delay", "0.96-0.97", "40×40px"), exact properties (`transition-property: scale, opacity`, `font-variant-numeric: tabular-nums`, `text-wrap: balance`, `-webkit-font-smoothing: antialiased`), named tokens (`shadow-subtle`/`shadow-overlay`), and Before/After example rows with real Tailwind classes (`active:scale-[0.96] transition-transform`). This fully matches the 5 anchor: executable examples covering the common cases.

Workflow Clarity

The review workflow is well defined: a Review Output Format ("markdown tables with Before and After columns, one table per principle"), a worked example section, a Review Checklist as an explicit verification pass, and a rule for empty results ("omit that table entirely"). This matches the 4 anchor (clear sequence, most checkpoints present) — a checklist and output contract exist, but there is no explicit ordering of check-then-report steps or loop-back guidance, keeping it below the 5 anchor's explicit validate/feedback-loop structure.

Progressive Disclosure

Structure is good on paper — a Quick Reference table mapping categories to files, inline principles kept brief, and one-level-deep references clearly signaled — but the four referenced files (typography.md, surfaces.md, animations.md, performance.md) do not exist in the skill bundle, so the disclosure path dead-ends. Verified against the actual bundle: no reference files are present, so navigation cannot complete. This falls between the 3 anchor (references present but undermined) and the 4 anchor (mostly clear references with minor gaps) — missing files are more than a minor organization gap, so 3.

Specificity

The 'what' ("Design engineering principles for making interfaces feel polished") is somewhat abstract, but the description enumerates several concrete activities — "building UI components, reviewing frontend code, implementing animations, hover states, shadows, borders, typography, micro-interactions, enter/exit animations" — matching the 'several specific actions with minor gaps' anchor rather than the fully comprehensive 5 or the 1-2-action 3.

Completeness

Both what ("Design engineering principles for making interfaces feel polished") and when ("Use when building UI components, reviewing frontend code... or any visual detail work") are explicitly stated, with an additional concrete trigger list. This matches the 5 anchor's pattern of a clear what + explicit when with concrete trigger phrases; it is clearly above the 4 anchor where 'when' is only serviceable.

Trigger Term Quality

Comprehensive natural trigger coverage including synonyms and CSS-specific terms users would actually say: "UI polish", "make it feel better", "feels off", "stagger animations", "border radius", "optical alignment", "font smoothing", "tabular numbers", "image outlines", "box shadows". No common variation is obviously missing, so the 4 anchor ('a few natural terms missing') fits worse.

Distinctiveness Conflict Risk

Clear niche (UI polish micro-details) with distinctive triggers like "tabular numbers", "optical alignment", and "stagger animations" that few other frontend/design skills would claim. Overlap with general styling skills is minimal, fitting the 'clear niche with distinct triggers' 5 anchor better than the 'minor overlap with closely related skills' 4 anchor.