motion-behavior-planner

Define each motion's user-facing purpose, trigger, start and end states, duration tier, and easing intent before implementation. This Skill guides that process and outputs a structured motion inventory and timing table ready for engineering handoff.

Replace large movements with opacity changes, instant state changes, or shorter durations while preserving the meaning the motion communicated. Critical state changes should always include a non-motion cue as well.

A complete spec covers motion purpose, triggers, start and end states, duration tiers, easing intent, sequencing, interruption behavior, reduced-motion alternatives, and performance boundaries such as compositor-friendly properties and concurrency limits.

Avoid motion that lacks a clear user-facing purpose, hides a usability or information-architecture problem, or runs on dense repeated surfaces where it harms performance. Motion should never block interaction or comprehension.

Define explicit rules for reversing, cancellation, debouncing, or state snapping when users navigate away, scroll, or repeat an action mid-motion. This prevents visual glitches and keeps the interface responsive.