Conciseness

Prose is minimal and code-heavy with no concept explanations, but the same mouse-to-NDC conversion snippet is repeated roughly six times (Quick Start, 'Basic Raycasting' setup, 'Mouse Position Conversion', 'Touch Support', 'Click to Select', 'Box Selection') and sections like the OrbitControls parameter list restate API defaults Claude already knows — matching 'mostly efficient but includes some unnecessary explanation or could be tightened'.

Actionability

Nearly all code is concrete, copy-paste ready, and covers the common cases (click select, hover, touch, drag, five control types with their update-loop calls), fitting 'mostly executable guidance; concrete code or commands with minor gaps'. Minor gaps: InteractionManager.dispose() is an empty stub with a '// Remove event listeners' comment, the deprecated `Face3` type appears in the intersection listing, and the PointerLockControls keyboard handler never resets flags on keyup.

Workflow Clarity

As a pattern catalog rather than a linear workflow, each section still presents a complete, correctly-ordered sequence — construct controls, configure options, call controls.update() in the animate loop (explicitly flagged 'Required for damping and auto-rotate'), and disable orbit controls while dragging via 'dragging-changed'. This matches 'clear sequence with most checkpoints present; minor validation gaps'; no destructive or batch operations exist that would require validation checkpoints.

Progressive Disclosure

Section headers are clear and well-ordered, but the entire ~650-line catalog is inlined in SKILL.md with no bundle files — the per-control API listings (FlyControls, FirstPersonControls, TrackballControls, MapControls) and the selection-system details would fit naturally in one-level-deep reference files, matching 'some structure... content that should be separate is inline'.

Specificity

The description names the domain and lists several concrete capabilities — 'raycasting, controls, mouse/touch input, object selection' — comparable to the anchor example 'Extracts text from PDF files, fills forms, converts pages to images'. Minor gaps in coverage (hover effects, keyboard input, world/screen coordinate conversion are covered in the body but unmentioned) keep it below the comprehensive level 5.

Completeness

It explicitly answers both what ('raycasting, controls, mouse/touch input, object selection') and when ('Use when handling user input, implementing click detection, adding camera controls, or creating interactive 3D experiences') with concrete trigger phrases, directly matching the level-5 anchor pattern. The 'when' clause is present, specific, and multi-scenario.

Trigger Term Quality

Trigger phrases like 'handling user input', 'implementing click detection', 'adding camera controls', and 'creating interactive 3D experiences' are natural phrases users would say, matching 'Good keyword coverage; a few natural terms missing'. It misses common synonyms and specifics users might mention ('3D picking', 'hover', 'OrbitControls', 'drag and drop'), so it falls short of the comprehensive synonym coverage of level 5.

Distinctiveness Conflict Risk

'Three.js interaction' carves a clear niche with distinct interaction-specific triggers, but phrases like 'adding camera controls' and 'creating interactive 3D experiences' carry minor overlap risk with closely related sibling skills (threejs-fundamentals, threejs-animation referenced in See Also), matching 'Mostly distinct; minor overlap risk with closely related skills'.