Conciseness

The 104-line body is telegraphic throughout: every line is a command, flag, default, or decision rule ("Box downscale with premultiplied alpha on a grid pinned to the feet, then clean alpha. Never nearest, never an upscale."), and bulk detail is pushed to reference files. No explanations of concepts Claude already known appear anywhere, and no padded sections were found to trim.

Actionability

Every step gives an exact, copy-paste-ready invocation ("python "<skill-dir>/scripts/sprite_set.py" plan --master <art>/master.json --output-dir <set>") with defaults, exit codes ("errors print `error: ...` and exit 1; usage errors exit 2"), and recovery commands; all scripts named in the body exist in scripts/. Only minor parameter formats (e.g. `--spans <spans>`) are delegated to a clearly linked reference, which keeps it at the top anchor rather than below it.

Workflow Clarity

Both flows are numbered and sequenced (sprite-set steps 1-6; one-clip pipeline steps 1-9) with explicit validation checkpoints at every gate ("register_clip.py qc", "video2dsprite.py triage", "read frames-clean/matte-report.json", "engine_export.py verify", "validate_animation.py") and explicit feedback loops ("up to 3 takes, each retake carrying the fix clause for the gate that failed", "Run it again to resume; nothing is generated twice"). The batch-generation workflow even hard-codes human review: "Never call an action approved before you have looked at its sheet".

Progressive Disclosure

The body is a true overview (108 lines) over 11 real reference files, each verified present in the bundle (sprite-set.md, motion-prompts.md, pipeline.md, matte.md, animation-review.md, prompt-rules.md, finishing.md, packed-alpha-runtime.js, runtime/packed-alpha-webgl.mjs, runtime/forge-runtime.mjs, schemas/video.schema.json) and clearly signaled at point of use ("Details: [pipeline.md](references/pipeline.md), keying [matte.md](references/matte.md), review and cuts [animation-review.md](references/animation-review.md), prompts [prompt-rules.md](references/prompt-rules.md)"). References are one level deep and organized by concern, with the body carrying only summary-level defaults.

Specificity

The description lists the full concrete pipeline: "gate each take, key it with a soft matte, register it to the master, pick loops or retime actions, finish (HD by default, pixel on request) and package fixed-canvas frames, alpha WebM, packed MP4 for iPhone and a PNG fallback with engine metadata and a JS runtime. Also processes a supplied clip." This is comprehensive, format-level coverage of input, routing, gating, keying, registration, timing, finishing, and packaging — above anchor 4, which allows minor coverage gaps.

Completeness

Both questions are answered explicitly: the "what" is the full pipeline above, and the "when" is a concrete trigger clause — "Use for character and creature animation, fluid motion and any video-to-sprite work" — reinforced by a supplied-clip case ("Also processes a supplied clip") and explicit exclusions ("Not for FX, icon or prop sheets (generate2dsprite), maps or plate loops (generate2dmap), code-drawn animation (codeart2d, only on request) or calling a video API by itself (generate2dmedia)").

Trigger Term Quality

Good natural coverage: "animated sprite set", "character and creature animation", "fluid motion", "video-to-sprite work", the action names ("idle, walk, run, attack, jump, hurt, cast"), and format terms ("alpha WebM", "packed MP4", "PNG"), with synonyms (character/creature, animation/motion). It falls short of anchor 5's comprehensive natural-term coverage — common user phrasings like "sprite sheet", "game character", or "animate my character" are absent — but is well above anchor 3's partial coverage.

Distinctiveness Conflict Risk

The niche (one master still → video-model sprite set) is distinct, and every adjacent skill is explicitly disambiguated by name in the "Not for..." clause (generate2dsprite, generate2dmap, codeart2d, generate2dmedia), which is exactly the negative-boundary pattern the top anchor rewards. Conflict risk with sibling media skills is minimal.