Conciseness

Lean throughout — sections open directly with executable code or terse GSAP-specific spec bullets ("Absolute: `1` — start at 1 second", "`<` — start when recently-added animation starts"); there is no generic GSAP introduction, no library-philosophy padding, and no re-explanation of concepts Claude already knows, so every token earns its place.

Actionability

All examples are fully executable, copy-paste-ready GSAP code covering the common cases — timeline creation, position parameters ("+=0.5", "<", "labelName+=0.3"), constructor defaults, addLabel, nesting, and playback methods — plus concrete ✅/❌ do-and-don't guidance rather than vague direction.

Workflow Clarity

A single-purpose reference skill with no multi-step process and no destructive or batch operations (so no validation cap applies); the single action — constructing a sequenced timeline — is unambiguous, organized in logical progression (create → place → defaults → labels → nest → control), and reinforced by best-practice and anti-pattern checklists, meeting the rubric's simple-skill condition for a 5.

Progressive Disclosure

A self-contained single-file skill (~104 lines) with clear section headers, no buried or dangling file references, and well-signaled navigation via the "Related skills" pointers (gsap-core, gsap-scrolltrigger, gsap-react); at this size no external split is needed, and the organization makes navigation easy.

Specificity

Names the domain and multiple concrete capabilities — "gsap.timeline(), position parameter, nesting, playback" — matching the anchor for multiple specific concrete actions with comprehensive coverage; only trivial omissions (labels, defaults) keep it from being distinguishable from the anchor-5 example, which itself lists four actions.

Completeness

Explicitly answers both what ("Official GSAP skill for timelines — gsap.timeline(), position parameter, nesting, playback") and when ("Use when sequencing animations, choreographing keyframes, or when the user asks about animation sequencing, timelines, or animation order") with concrete trigger phrases — an exact anchor-5 match.

Trigger Term Quality

Natural user phrasing is comprehensively covered with synonyms — "sequencing animations", "choreographing keyframes", "animation sequencing", "timelines", "animation order" — mirroring the anchor-5 example's synonym coverage; no common variation a user would say is missing.

Distinctiveness Conflict Risk

Clear niche (GSAP timeline sequencing) with specific API names, but broad phrases like "animation sequencing" and the explicit "(in GSAP or when recommending a library that supports timelines)" invite triggering outside the core niche and create minor overlap with closely related sibling skills (gsap-core for general animation questions, gsap-scrolltrigger for timelines) — anchor 4 ("mostly distinct; minor overlap risk with closely related skills") fits better than anchor 5's "minimal conflict risk".