Conciseness

The ~20-line body is lean with zero padding: no concepts Claude already knows are explained, and every sentence carries direct instruction ("Reproduce first, with the same command and URL the user had"), matching the every-token-earns-its-place anchor.

Actionability

Concrete, executable instruction throughout — a reproduction procedure, an owner-module taxonomy ("renderer, loop, camera, scene, assets, audio, input, physics, UI, or base path"), a bottleneck classification ("CPU, GPU draw, fragment, vertex, memory, or network"), and one-variable-change re-measure discipline — but the body itself contains no copy-paste commands or tool specifics, which are delegated to the playbook, leaving minor gaps against the fully-executable anchor.

Workflow Clarity

Sequences are explicit with validation checkpoints and feedback loops: "fix the root cause there, and retest the exact broken path", "change one thing, and re-measure the same scenario, confirming visuals and playability held", and "verify the affected path after a fix". This is not a destructive or batch operation, so the validation cap does not apply.

Progressive Disclosure

A lean overview body points to exactly one one-level-deep reference (references/debug-playbook.md, which exists and covers the promised triage and profiling content), clearly signaled with both a scope summary and a read-trigger ("Read it when debugging or profiling anything non-obvious").

Specificity

The description enumerates a comprehensive set of concrete capabilities across both debugging ("blank canvases, render and runtime bugs, asset and audio loading, animation, resize, mobile input") and profiling ("draw calls, triangles, textures, memory, shader and post-processing cost, and bundle size"), matching the comprehensive-coverage anchor with no identifiable gaps.

Completeness

The "what" is clear and comprehensive, but there is no "Use when..." clause or equivalent explicit trigger guidance, so the "when" is only weakly implied by the domain listing; per the rubric guideline this caps completeness at 3.

Trigger Term Quality

Good natural-term coverage ("Three.js", "blank canvases", "asset loading", "draw calls", "bundle size") but misses common synonyms and variations users would actually say, such as "WebGL", "white screen", "slow"/"lagging", "frame rate"/"FPS", and ".glb"/"glTF".

Distinctiveness Conflict Risk

"Three.js browser games" is a clear niche with distinct, specific triggers (blank canvas, post-processing cost, draw calls) that are unlikely to collide with other skills.