Conciseness

The one-line-per-term glossary format is inherently lean and the instructions avoid padding, but a noticeable subset of entries restate concepts Claude already knows ("Duration — How long an animation takes", "Delay — Time before an animation starts", Scale, Rotate, Skew, Linear, Jank). Not a 2 because most content is the skill's genuine payload; not a 4 because those trivially-known entries are a real trimming opportunity.

Actionability

For an instruction-only skill the guidance is fully actionable: an exact output format template, three concrete user-input-to-output examples (feel-based, disambiguation, physics feel), explicit disambiguation pairs (Clip-path vs Mask, Pop in vs Bounce), and a defined fallback ("name the closest term and say plainly it's an approximation"). The verbatim-quote rule is executable since the glossary is embedded. Matches the level-5 anchor's coverage of common cases.

Workflow Clarity

A single-purpose lookup task whose sequence is unambiguous: read for intent → quote glossary verbatim → disambiguate close terms → output in the fixed format, with alternates and fallback rules specified. Per the simple-skill note a single unambiguous action scores 5, and no validation cap applies since the operation is non-destructive.

Progressive Disclosure

The body is well organized (Initial Response, Quick Start, Instructions, Examples, Glossary with 12 labeled subsections) with no buried or nested references. Not a 5 because the ~120-line glossary — the bulk of the content — is inlined in SKILL.md rather than split into a one-level-deep reference file, which would keep the main file a lean overview; but it is far from the inlined-unstructured-content of lower anchors.

Specificity

"Reverse-lookup glossary that turns a vague description of a web animation or motion effect into its exact term" names the domain and concrete action, backed by two worked input-to-output examples ("the bouncy thing when a popover opens" → Pop in). It exceeds the level-3 anchor (domain + 1-2 actions without comprehensiveness) thanks to the examples and explicit scope boundary, but describes one core action rather than the multiple distinct actions of the level-5 anchor.

Completeness

Both halves are explicit: what it does ("Reverse-lookup glossary that turns a vague description… into its exact term") and when to use it ("Use when the user asks 'what's it called when…', or describes a motion effect without knowing its name"), with concrete trigger phrases. This matches the level-5 anchor; a 4 would require the 'when' clause to be less specific, which it is not.

Trigger Term Quality

It quotes the natural phrases users would actually say verbatim — "what's it called when…", "the bouncy thing when a popover opens", "the iOS rubber-band scroll" — which is exactly the right trigger language. Not a 5 because common synonyms like "micro-interaction", "transition", or "what's the name of that effect" are missing.

Distinctiveness Conflict Risk

A clear niche (naming web animation effects) with an explicit boundary clause — "For naming an effect, not designing or building one" — that fences it off from animation-implementation skills. Minimal conflict risk, matching the level-5 anchor.