Conciseness

The bulk is valuable API-specific reference code, but the ~90-line "Procedural Animation Patterns" section (smooth-damp math, a generic Spring class, sine-wave oscillation) largely re-explains math and physics Claude already knows — more than the "minor instances" of anchor 4, fitting anchor 3.

Actionability

Nearly every section ships executable, copy-paste-ready code covering the common cases end to end (GLTF load → mixer → clipAction → play → update loop, crossfade, weight blending, morph targets). Only peripheral snippets reference undefined helpers (isInFrustum, loadClip, weaponGeometry), which is minor relative to full coverage.

Workflow Clarity

Core flows are shown as clear, unambiguous sequences (mixer.update in the render loop, GLTF load-and-play, crossfade ordering with play-then-fade), and no destructive or batch operations require validation. It falls short of anchor 5 because the document is organized as a topic-by-topic API reference rather than end-to-end workflows with explicit checkpoints.

Progressive Disclosure

No bundle files exist, so all ~550 lines are inlined. Section headers give it real structure (above anchor 2's "minimal structure"), but the KeyframeTrack types, AnimationAction property listing, and Animation Utilities sections are 200+ lines of API reference that belong in a references/ file — matching anchor 3's example exactly.

Specificity

Lists multiple specific concrete capabilities — "keyframe animation, skeletal animation, morph targets, animation mixing" — plus "playing GLTF animations" and "creating procedural motion", giving comprehensive coverage of the Three.js animation domain with no meaningful gaps (anchor 5, not 4).

Completeness

Explicitly answers both "what" (keyframe, skeletal, morph targets, mixing) and "when" via a concrete "Use when..." clause with multiple trigger phrases, matching the anchor-5 example pattern exactly rather than the anchor-4 case where the when-clause could be more specific.

Trigger Term Quality

Triggers "animating objects, playing GLTF animations, creating procedural motion, or blending animations" are natural phrases a user would say, but common variations like "bones", "rig", "walk cycle", or the ".glb" extension are missing, fitting anchor 4 rather than 5.

Distinctiveness Conflict Risk

"Three.js animation" is a clear niche, but the body's See Also reveals closely related sibling skills (threejs-loaders, threejs-shaders) and "playing GLTF animations" slightly overlaps with a loaders skill — mostly distinct with minor overlap risk (anchor 4, not 5).