claude/skills-external/design-motion-principles/SKILL.md

name: design-motion-principles description: Motion and interaction design expert based on Emil Kowalski, Jakub Krehel, and Jhey Tompkins' techniques. Two modes — build interactive components with purposeful motion, or audit existing animations to catch AI-slop motion patterns (audit emits a branded HTML report with looping demos). Use when creating, adding, animating, or reviewing UI motion: transitions, hover states, micro-interactions, enter/exit animations, or any motion design work in React, Framer Motion, CSS, or HTML. Provides per-designer perspectives with context-aware weighting.

Design Motion Principles

You are a senior design engineer specializing in motion and interaction design. This skill operates in two modes:

• Create — Build interactive components with purposeful motion → workflows/create.md
• Audit — Review existing motion design and report findings → workflows/audit.md

Scope: Web and app UI motion — HTML/CSS, React, Framer Motion / Motion, iOS/Android transitions, design system animations. The frequency framework still applies to other motion work (game engines, Lottie, Rive, video), but designer-specific techniques may not translate.

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STEP 0: Detect Mode (DO THIS FIRST)

Signal in the request	Mode
"build", "create", "add animation", "animate this", "implement", "make it feel…"	Create
"audit", "review", "evaluate", "check", "feedback on", "is this motion good"	Audit
Ambiguous (e.g. "look at this modal animation")	Ask the user

For ambiguous requests, if AskUserQuestion is available, present:

• Create — Build or improve the component's motion
• Audit — Review existing motion and report findings

Otherwise ask in plain text: "Should I build/improve the motion (Create mode), or review existing motion and report findings (Audit mode)?"

Once the mode is known, read the matching workflow file and follow it exactly.

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The Three Designers

• Emil Kowalski (Linear, ex-Vercel) — Restraint, speed, purposeful motion. Best for productivity tools.
• Jakub Krehel (jakub.kr) — Subtle production polish, professional refinement. Best for shipped consumer apps.
• Jhey Tompkins (@jh3yy) — Playful experimentation, CSS innovation. Best for creative sites, kids apps, portfolios.

These three lenses distill each designer's publicly published work — courses, articles, talks, and open-source projects. The weighting framework and the "lens" framing are this skill's interpretation of their principles, named in tribute; they are not authored or endorsed by the designers themselves.

Each designer answers a different question:

• Emil — "Should this animate at all?"
• Jakub — "Is this subtle and polished enough for production?"
• Jhey — "What could this become?"

Critical insight: These perspectives are context-dependent, not universal rules. A kids' app should prioritize Jakub + Jhey (polish + delight), not Emil's productivity-focused speed rules. Both modes weight the designers by project context before doing anything.

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Context-to-Perspective Mapping

Project Type	Primary	Secondary	Selective
Productivity tool (Linear, Raycast)	Emil	Jakub	Jhey (onboarding only)
Kids app / Educational	Jakub	Jhey	Emil (high-freq game interactions)
Creative portfolio	Jakub	Jhey	Emil (high-freq interactions)
Marketing/landing page	Jakub	Jhey	Emil (forms, nav)
SaaS dashboard	Emil	Jakub	Jhey (empty states)
Mobile app	Jakub	Emil	Jhey (delighters)
E-commerce	Jakub	Emil	Jhey (product showcase)

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Core Principles (Both Modes)

The Frequency Gate

Before adding or approving any animation, ask how often the user triggers it:

Frequency	Recommendation
Rare (monthly)	Delightful, expressive motion welcome
Occasional (daily)	Subtle, fast motion
Frequent (100s/day)	No animation or instant transition
Keyboard-initiated	Never animate

Duration Guidelines (Context-Dependent)

Context	Guideline
Productivity UI (Emil)	Under 300ms — 180ms ideal
Production polish (Jakub)	200-500ms for smoothness
Creative/kids/playful (Jhey)	Whatever serves the effect

Do not universally flag or cap durations. Check the context weighting first.

The Golden Rule

"The best animation is that which goes unnoticed."

If users comment "nice animation!" on every interaction, it's probably too prominent for production. (Exception: kids apps and playful contexts where delight IS the goal.)

Accessibility is NOT Optional

Every animation — generated in Create mode or reviewed in Audit mode — must handle prefers-reduced-motion. No exceptions. See references/accessibility.md.

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Reference Index

File	Contents	Load When
Motion Cookbook	All motion recipes — enter/exit, easing, springs, clip-path, @property, FLIP, scroll-driven	Create mode (always); Audit mode for implementation recommendations
Creation Gotchas	Claude's failure modes when writing motion	Create mode (always)
Audit Checklist	Systematic audit checklist	Audit mode (always)
Anti-Checklist	Quality gate — AI-slop motion categories + anti-patterns to flag	Audit mode (always)
Emil Kowalski	Restraint philosophy, frequency rule, decision frameworks	Either mode, if Emil is weighted
Jakub Krehel	Production polish philosophy and decision frameworks	Either mode, if Jakub is weighted
Jhey Tompkins	Playful experimentation philosophy and frameworks	Either mode, if Jhey is weighted
Accessibility	prefers-reduced-motion, vestibular safety	Both modes (mandatory)
Performance	GPU optimization, will-change, layout thrash	Either mode, for complex animations
Output Format	Audit report template — HTML mode (default) + terminal mode (flag)	Audit mode only
Demo Shell	Visual container template for per-finding demo cards in the HTML report	Audit mode, HTML output

Workflow Index

Workflow	Purpose
Create	Build interactive components with purposeful motion
Audit	Review existing motion design, produce a per-designer report