The body is lean: concrete rules and tight code snippets with no over-explanation of CSS, SVG, or shadow concepts Claude already knows, fitting the 'every token earns its place' anchor.

Guidance is fully executable — copy-paste CSS for font smoothing, image outlines, and transition properties, plus specific values like 44x44px hit areas, scale(0.96), and 150ms — meeting the copy-paste-ready anchor.

As a single-purpose skill, its flow is unambiguous: apply named principles, report before/after rows, then run the closing checklist; no destructive or batch operation is present that would require validation checkpoints.

Content is well-organized into clearly headed sections (When to Use, Core Principles, Review Output, Checklist) with no nested external references; the self-contained single file is appropriately structured for a reference-style skill.

The description enumerates many concrete domains — "spacing, typography, borders, shadows, motion, hit areas, icons, text wrapping, and interaction states" — matching the anchor for listing multiple specific concrete actions.

It explicitly answers what ("Apply concrete design-engineering details that make interfaces feel polished") and when ("Use when reviewing or improving UI spacing…"), satisfying both halves with an explicit trigger clause.

It uses natural terms users would say ("UI", "spacing", "typography", "borders", "shadows") with broad coverage; not merely jargon or a single variation, so it sits above the score-2 anchor.

It carves a clear niche (interface polish / design-engineering details) with distinct triggers, making it unlikely to fire for the wrong skill; not generic enough to fall to the score-2 anchor.