Motion skills compared: Emil Kowalski, GSAP, Lottie

An agent asked to "add some motion" reaches for transition-all, fades every section in on scroll and forgets prefers-reduced-motion. The open motion skills fix this from different angles: one author's taste, one library's API, one studio's choreography tables. For most projects I would install motion from molveau/skills. It merges Emil Kowalski's skills, the official GSAP skills, LottieFiles' motion-design, Benji Taylor's stageshow and Raphael Salaja's 12 principles into one playbook, and adds a checker script. If you only want Emil Kowalski's animation taste, install his skills; the sections below say when each original is the better choice.

The contenders

Skill	Author	Licence	Best at	Lacks
skills	Emil Kowalski	MIT	Deciding whether and how something animates; reviews and audits	Scroll timelines and library depth
gsap-skills	GreenSock	MIT	Using GSAP correctly: tweens, timelines, ScrollTrigger, React cleanup	Whether something should animate at all
motion-design-skill	LottieFiles	MIT	Choreography, personality and timing tables	Product UI restraint: it favours ambient layers
stageshow	Benji Taylor	MIT (code)	Faux product UI and animated demos in React	Everyday interface motion
12-principles-of-animation	Raphael Salaja	MIT	Auditing code against Disney's principles adapted for the web	Upstream availability: the author has removed it
motion	Molveau Studio	MIT	One playbook from the gate to the audit, with guardrails and a checker	Emil's newer skills and three of the eight GSAP skills

Each one, fairly

Emil Kowalski's skills

Emil's skills are the ones I would keep if I could keep only one set. animate builds an animation by making decisions in the order that determines whether it feels right, review-animations critiques a diff, improve-animations audits a codebase, find-animation-opportunities finds what should move and rejects the rest, and apple-design covers springs and gestures. His repo now also has skills I do not merge, such as animate-expo for React Native and animation-performance. If you want his taste and nothing else, or you build in Expo, install his repo.

GSAP skills, by GreenSock

The official skills teach an agent the GSAP API as GreenSock intends it: core tweens and easing, timelines, ScrollTrigger pinning and scrubbing, useGSAP cleanup in React, performance. My skill vendors five of the eight (core, react, scrolltrigger, timeline, performance). If you lean on Flip, SplitText or Draggable, or work in Vue or Svelte, install GreenSock's full set for its plugins, utils and frameworks skills.

motion-design-skill, by LottieFiles

LottieFiles wrote the most thorough choreography reference I have found: motion personality archetypes, duration and easing tables, emotion-to-motion mapping and patterns for state feedback. It works with any animation system. Its taste runs richer than mine (ambient layers, overshoot pops), so on a brand or illustration project the original is a fine install on its own.

stageshow, by Benji Taylor

stageshow helps an agent build faux product UI that looks like the real product: stills, feature cards, cursor demos and bento grids, with a kit and tools that film the result. My copy leaves out its third-party artwork, its filming scripts and the example scenes that replicate real products. If you want the filming gate and every example, install Benji's repo.

12 principles of animation, by Raphael Salaja

This skill audits motion code against Disney's twelve principles adapted for the web and reports findings by file:line. Raphael archived and then removed it from his repo in October 2026, so the copy in my motion skill is pinned to its last published version. His current repo has a newer motion skill with his own house rules, worth reading if you like his approach.

What the merged skill adds

• Routing. One install. The SKILL.md maps each task to a file: a new animation opens Emil's animate, scroll pinning opens GSAP's scrolltrigger, a product demo opens stageshow, choreography tables open LottieFiles.
• Pinned, unedited copies under references/vendor/, each at a pinned commit. A weekly GitHub Action checks upstream and opens an issue when a source moves; a person reviews each bump.
• A playbook that settles disagreements. The ease-out curve: Emil uses (0.23, 1, 0.32, 1), unslop (0.22, 1, 0.36, 1), LottieFiles (0.2, 0, 0, 1); the playbook asks for one token per project and Emil's when there is none. Reduced motion: Emil and LottieFiles make it gentler, GSAP sets duration to zero; the playbook shows the final state and keeps spinners and press feedback.
• Guardrails. Animate transform and opacity on one ease-out token, never transition-all, no reveal-on-scroll by default, every loop paused off screen and on a hidden tab.
• A checker. check-motion.mjs has no dependencies and runs on Node 20. It flags scroll-reveal libraries, whileInView, transition-all, transform in arbitrary transition lists, and animation loops or keyframes in a file with no reduced-motion handling.

Install

The skill alone, with the skills CLI:

npx skills add molveau/skills -s motion

The design bundle:

npx skills add molveau/skills -s anti-slop -s ui -s ux -s motion -s design-grill -s design-inspiration-index

In Claude Code, all eleven skills as one plugin:

/plugin marketplace add molveau/skills
/plugin install molveau-skills@molveau

Every skill and bundle is on the skills page, and the source is at github.com/molveau/skills. Related comparisons: anti-slop skills, UI skills, UX and accessibility skills.

Checklist

• Each animation has a named purpose, and frequent actions mostly do not animate.
• Only transform and opacity move, listed by name, on the project's ease-out token.
• Reduced motion shows the final state.
• Loops pause off screen and on a hidden tab.
• check-motion.mjs runs clean on the changed files, or each finding is explained.
• If you need Expo, GSAP plugins or stageshow's filming, the original is installed too.