Motion Design

---
name: motion-design
description: "Engineer purposeful interface motion, transitions, continuity, gestures, and direct manipulation after a web, mobile, desktop, or incumbent art-direction owner defines the visual thesis. Use when motion complexity exceeds simple incumbent transitions. Exclude art direction, static art, routine styling, and non-visual performance work."
---

# Motion Design

Implement the selected owner’s motion character. Do not invent another visual or interaction thesis.

## Start with the job

Inspect product context, established direction, state model, platform, inputs, accessibility commitments, incumbent motion system, installed framework and versions, performance evidence, and available validation capabilities.

Ask only when the motion’s purpose, hierarchy, interaction contract, or permitted intensity remains materially ambiguous. Missing libraries, rendering, browser tools, simulators, or devices do not block a source-level solution or honest limitation report.

## Load only relevant guidance

- Read [references/motion-decisions.md](references/motion-decisions.md) before introducing substantial motion or choosing its character.
- Read [references/transitions-continuity.md](references/transitions-continuity.md) for state transitions, spatial continuity, choreography, and interruption.
- Read [references/gestures-input.md](references/gestures-input.md) for pointer, touch, keyboard, direct manipulation, comparison controls, or hold interactions.
- Read [references/accessibility-performance-validation.md](references/accessibility-performance-validation.md) for reduced motion, performance decisions, and final validation.

## Preserve boundaries

Motion must explain state, relationship, continuity, feedback, priority, or one earned expressive moment. Frequency and task pressure matter: repeated expert actions usually need less ceremony than an occasional narrative transition.

Prefer the incumbent platform or framework for simple motion. Add no dependency merely for convenience. Inspect installed versions and current primary documentation before giving library-specific APIs. Durations, easing, springs, scale, blur, stagger, and transform origin are starting hypotheses shaped by distance, hierarchy, frequency, input, interruption, and platform, not universal rules.

Motion may be triggered by pointer, touch, keyboard, system state, or programmatic change when it communicates meaning. Every interaction must remain usable when motion is reduced, replaced, unavailable, interrupted, or reversed.

## Finish with evidence

Validate the actual transition or interaction when capability exists. Exercise rapid repetition, interruption, reversal, cancellation, long content, focus, assistive technology, reduced motion, and representative devices or browsers. Measure performance when claiming improvement; otherwise report risk without a score.

Use one bounded correction pass and confirm. Repeat only for a remaining material defect. Never claim rendering, frame stability, device fidelity, or accessibility validation that was not performed.