# gsap-web

Helps AI coding assistants write GSAP animations, from sequenced timelines and ScrollTrigger effects to SplitText, Flip, and Lenis smooth scroll.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 2500 installs · ★ 58
- Author: iart-ai
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/iart-ai/web-animation-skills/tree/HEAD/skills/gsap-web/SKILL.md
- Updated: 2026-06-22
- HTML: https://affpapa.org/en/nevibecode/skills/gsap-web

## What it does

This skill teaches the assistant how to write web motion code using GSAP 3.12+. It covers sequenced timelines, pinned scroll sections, horizontal scrolling, text reveals via SplitText, and layout morphing with Flip.

A core focus is syncing ScrollTrigger with smooth-scroll libraries like Lenis and Locomotive. The skill directs the agent to drive Lenis from `gsap.ticker` while converting seconds to milliseconds with `* 1000` and disabling lag smoothing with `lagSmoothing(0)`. This setup eliminates jitter and keeps ScrollTrigger markers aligned.

GSAP plugins must be registered via `gsap.registerPlugin()` right at app entry, or they silently fail to execute. For SplitText animations, the skill also enforces waiting for `document.fonts.ready` so recalculated line breaks never break the DOM.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add iart-ai/web-animation-skills --skill gsap-web -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/gsap-web/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/gsap-web/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add iart-ai/web-animation-skills --skill gsap-web -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/gsap-web/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add iart-ai/web-animation-skills --skill gsap-web -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/gsap-web/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install iart-ai/web-animation-skills gsap-web
```

2. **Manually: put the files in place**
- File: `.github/skills/gsap-web/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add iart-ai/web-animation-skills --skill gsap-web -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/iart-ai/web-animation-skills --path skills/gsap-web
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/gsap-web/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add iart-ai/web-animation-skills --skill gsap-web -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/iart-ai/web-animation-skills/tree/HEAD/skills/gsap-web/SKILL.md

## When to use it
- pin a section during scroll using ScrollTrigger
- sync Lenis smooth scroll with the GSAP ticker
- split text into lines and animate word reveals
- orchestrate sequenced timelines with overlap controls

## Example prompts
- Build a horizontal scroll section pinned with ScrollTrigger
- Sync ScrollTrigger with Lenis so pins and markers do not jitter
- Create a hero text reveal using SplitText after fonts load

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: c3b42d88be2445e1.

BEGIN THIRD-PARTY FILE c3b42d88be2445e1
````text
---
name: gsap-web
description: This skill should be used when the user asks to "build a scroll animation", "add ScrollTrigger", "pin a section while scrolling", "scrub an animation to scroll", "create a hero timeline", "do a horizontal scroll section", "split text and animate words", "animate a layout change with GSAP Flip", "sync ScrollTrigger with Lenis", "Lenis smooth scroll jittery", "ScrollTrigger markers drift", "ScrollTrigger pins break with Lenis/Locomotive", or "set up smooth scroll with GSAP pinning". Covers GSAP timelines, ScrollTrigger, SplitText, Flip, and Lenis/Locomotive smooth-scroll sync for code-driven web motion.
version: 0.1.0
---

# GSAP for the Web

GSAP (GreenSock Animation Platform) is the workhorse for code-driven web motion: sequenced timelines, scroll-driven storytelling, text reveals, and layout transitions. As of GSAP 3.12+, every plugin (ScrollTrigger, SplitText, Flip, MotionPath, MorphSVG, Draggable, Observer) is 100% free, including for commercial use.

## When to use

- Scroll-driven storytelling: pinned sections, parallax, progress scrubbing, horizontal scroll
- Sequenced hero animations and complex multi-element timelines with precise overlap control
- Text reveals split into chars/words/lines (SplitText)
- Layout transitions where an element changes position/size/parent (Flip)
- Any motion needing fine timing control, easing precision, or imperative orchestration

## Install and register

```js
import gsap from "gsap";
import { ScrollTrigger } from "gsap/ScrollTrigger";
import { SplitText } from "gsap/SplitText";
import { Flip } from "gsap/Flip";

gsap.registerPlugin(ScrollTrigger, SplitText, Flip);
```

Plugins MUST be registered before use or they silently no-op. With a bundler, register once at app entry.

## Core techniques

### Timelines first

Prefer one timeline over many independent tweens — it gives a single playhead, relative positioning, and easy reversal.

```js
const tl = gsap.timeline({ defaults: { ease: "power3.out", duration: 0.6 } });
tl.from(".title", { yPercent: 100, opacity: 0 })
  .from(".sub",   { y: 20, opacity: 0 }, "-=0.3")  // start 0.3s before prev ends
  .from(".cta",   { scale: 0.9, opacity: 0 }, "<"); // align to prev tween START
```

Position parameter cheat sheet:
- `"+=0.5"` / `"-=0.3"` — relative to the end of the timeline (gap / overlap)
- `"<"` — start of the previous tween; `">"` — end of the previous tween
- `"<0.2"` — 0.2s after the previous tween's start
- `"myLabel"` — at a named label added via `tl.addLabel("myLabel")`

Use `.from()` for entrances (animates FROM the given values TO current CSS), `.to()` for exits, `.fromTo()` when both ends must be explicit (most robust against re-runs).

### gsap.to vs set vs quickTo

```js
gsap.set(el, { autoAlpha: 0 });           // instant, no tween (autoAlpha = opacity + visibility)
const xTo = gsap.quickTo(el, "x", { duration: 0.4, ease: "power3" });
window.addEventListener("pointermove", (e) => xTo(e.clientX)); // fast repeated updates
```
````
END THIRD-PARTY FILE c3b42d88be2445e1

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