Motion

One skill, three modes. Pick by intent; load only the matching reference file.

Mode	When	Reference
`audit`	Review existing animation code for quality -- outputs `file:line` findings against the 12 principles	references/audit-12-principles.md
`add`	Enhance a feature with new animations, micro-interactions, motion design	references/add-motion.md
`fix`	Animations stutter, transitions jank, perf review of CSS/JS motion	references/fix-performance.md

Invocation: /motion audit <files>, /motion add [target], /motion fix [file]. Bare /motion fix applies the performance constraints to all UI animation work in this conversation. If no mode is given, infer from the ask (review/check -> audit; add/enhance -> add; jank/slow/stutter -> fix).

Mode boundaries (the numbers differ by design)

Each mode's numeric rules apply only within that mode -- they intentionally disagree:

Stagger: audit enforces <=50ms per item on existing code; add recommends 100-150ms delays for page-load choreography. When adding motion that must later pass an audit, prefer the audit cap.
Feedback duration: audit fails user-initiated animations over 300ms; add allows 300-500ms for layout changes. Audit numbers win for interaction feedback.
Springs vs easing: audit prescribes springs for overshoot-and-settle; add bans bounce/elastic easing curves. Both are right: springs yes, bounce/elastic cubic-beziers no.