Conciseness

Every rule is repo-specific contract knowledge Claude could not already know ('Mutate board state through `setCell(x, z, opts)`', 'Keep Three.js pinned to r185 and self-hosted under `vendor/three/`'), with no general-concept padding; even the Cluso parenthetical earns its place by preventing rule reversal.

Actionability

Copy-paste-ready commands throughout: `npm test`, `npm run build`, `npm run vendor:three`, a working perl + `node --check` extraction pipeline, a browser validation URL, and the check.js regex with concrete ✓/✗ HTML examples covering the common failure case.

Workflow Clarity

An explicit Validation section with runnable commands and a stale-build diagnostic loop ('If browser stack traces point at ... run `npm run build`') provides real checkpoints, but the edit → test → browser-check sequence is implied by section order rather than laid out as an explicit workflow with fix/retry steps, so it falls short of the top anchor.

Progressive Disclosure

A compact (~56 line) single-file skill with clean sections (Core rules, Validation, script gotcha, Related durable systems) and one-level-deep, clearly-signaled deferrals to `.codex/skills/tinyworld-runtime-state` and `.codex/skills/tinyworld-island-and-planes`; no bundle files exist or are needed.

Specificity

Names the domain ('Tiny World Builder repo, especially tiny-world-builder.html') and 1-2 concrete actions ('preserve the static classic-script Three.js r185 app structure and local edit/reload workflow'), but does not enumerate several specific actions, matching the anchor for domain plus 1-2 actions rather than the several-actions anchor.

Completeness

Both parts are present: an explicit when ('Use when editing the Tiny World Builder repo') and a what ('to preserve the static classic-script Three.js r185 app structure and local edit/reload workflow'). Not a 5 because the 'what' is a single purpose clause rather than concrete enumerated capabilities with trigger phrases.

Trigger Term Quality

Good natural keyword coverage — 'editing', 'Tiny World Builder', 'tiny-world-builder.html', 'Three.js', 'r185' — anchored by the exact filename a user would mention; a few natural terms (e.g., 'island', 'builder app') are missing, so it sits at good-coverage rather than comprehensive-with-synonyms.

Distinctiveness Conflict Risk

Pinned to a single named repo, a specific HTML file, and a pinned Three.js version — a clear niche with distinct triggers and minimal conflict risk with any other skill.