Gsap Performance

---
name: gsap-performance
description: "Use when implementing, optimizing, and timing 60fps/120fps gsap performance animations, transitions, gesture physics, and reduced-motion fallbacks."
version: 6.0.0
last-updated: 2026-09-29
skills:
  - 60fps-animation
  - fixing-motion-performance
  - motion-engineering
tools: Read, Grep, Glob, Bash, Edit, Write
scripts-binding:
  - .agent/scripts/lint_runner.js
  - .agent/scripts/verify_all.js
---

# GSAP Performance — 60fps Animation Optimization

## Mandatory Pre-Flight Context Inspection
Before reading, generating, or refactoring code in the `gsap-performance` domain, inspect these 5 critical parameters:
1. **System Boundaries & Dependencies**: Verify that all required dependencies exist in target package manifests and environment paths.
2. **Runtime Context & Platform Invariants**: Confirm target platform constraints (Node.js, Browser, Mobile OS, Edge runtime) before applying APIs.
3. **Execution Guardrails**: Identify potential side-effects, state mutations, and unhandled asynchronous exceptions.
4. **Validation & Type Contracts**: Validate input data schemas and strict type constraints across all module interfaces.
5. **Observability & Proof of Execution**: Ensure execution produces tangible verification signals (terminal output, tests, metrics).


## Activation Boundaries
- **Activate when:** Use when implementing, optimizing, and timing 60fps/120fps gsap performance animations, transitions, gesture physics, and reduced-motion fallbacks.
- **DO NOT activate when:** The task falls outside the `gsap-performance` domain or is managed by a different dedicated specialist agent.


## 🔁 Multi-Pass Execution Protocol

| Pass | Phase | Core Action | Adaptive Depth |
|:---|:---|:---|:---|
| **Pass 1** | **Understand** | Deconstruct the user's explicit objective, implicit requirements, and platform constraints. | Fast / Standard / Deep |
| **Pass 2** | **Plan** | Decompose task into smallest logical steps; map dependencies, affected files, and tool calls. | Standard / Deep |
| **Pass 3** | **Execute** | Implement solution with production-grade craft, zero placeholders, and strict typing. | All Modes |
| **Pass 4** | **Verify** | Run linters, unit tests, or compiler checks to validate structural correctness. | All Modes |
| **Pass 5** | **Attack & Falsify** | Perform adversarial search for edge-case failures, counterexamples, race conditions, and traps. | Standard / Deep |
| **Pass 6** | **Harden** | Eliminate discovered friction, optimize performance, and harden error boundaries. | Standard / Deep |
| **Pass 7** | **Quality Gate** | Enforce Verification-Before-Completion (VBC) with concrete terminal proof before finalizing. | All Modes |


---

## 🛠️ Technical Architecture & Reference Recipes

## When to Use This Skill

Apply when optimizing GSAP animations for smooth 60fps, reducing layout/paint cost, or when the user asks about performance, jank, or best practices for fast animations.

**Related skills:** Build animations with **gsap-core** (transforms, autoAlpha) and **gsap-timeline**; for ScrollTrigger performance see **gsap-scrolltrigger**.

## Prefer Transform and Opacity

Animating **transform** (`x`, `y`, `scaleX`, `scaleY`, `rotation`, `rotationX`, `rotationY`, `skewX`, `skewY`) and **opacity** keeps work on the compositor and avoids layout and most paint. Avoid animating layout-heavy properties when a transform can achieve the same effect.

- ✅ Prefer: **x**, **y**, **scale**, **rotation**, **opacity**.
- ❌ Avoid when possible: **width**, **height**, **top**, **left**, **margin**, **padding** (they trigger layout and can cause jank).

GSAP’s **x** and **y** use transforms (translate) by default; use them instead of **left**/**top** for movement.

## will-change

Use **will-change** in CSS on elements that will animate. It hints the browser to promote the layer.

```css
will-change: transform;
```

## Batch Reads and Writes

GSAP batches updates internally. When mixing GSAP with direct DOM reads/writes or layout-dependent code, avoid interleaving reads and writes in a way that causes repeated layout thrashing. Prefer doing all reads first, then all writes (or let GSAP handle the writes in one go).

## Many Elements (Stagger, Lists)

- Use **stagger** instead of many separate tweens with manual delays when the animation is the same; it’s more efficient.
- For long lists, consider **virtualization** or animating only visible items; avoid creating hundreds of simultaneous tweens if it causes jank.
- Reuse timelines where possible; avoid creating new timelines every frame.

## Frequently updated properties (e.g. mouse followers)

Prefer **gsap.quickTo()** for properties that are updated often (e.g. mouse-follower x/y). It reuses a single tween instead of creating new tweens on each update.

```javascript
let xTo = gsap.quickTo('#id', 'x', { duration: 0.4, ease: 'power3' }),
  yTo = gsap.quickTo('#id', 'y', { duration: 0.4, ease: 'power3' });

document.querySelector('#container').addEventListener('mousemove', e => {
  xTo(e.pageX);
  yTo(e.pageY);
});
```

## ScrollTrigger and Performance

- **pin: true** promotes the pinned element; pin only what’s needed.
- **scrub** with a small value (e.g. `scrub: 1`) can reduce work during scroll; test on low-end devices.
- Call **ScrollTrigger.refresh()** only when layout actually changes (e.g. after content load), not on every resize; debounce when possible.

## Reduce Simultaneous Work

- Pause or kill off-screen or inactive animations when they’re not visible (e.g. when the user navigates away).
- Avoid animating huge numbers of properties on many elements at once; simplify or sequence if needed.

## Best practices

- ✅ Animate **transform** and **opacity**; use **will-change** in CSS only on elements that animate.
- ✅ Use **stagger** instead of many separate tweens with manual delays when the animation is the same.
- ✅ Use **gsap.quickTo()** for frequently updated properties (e.g. mouse followers).
- ✅ Clean up or kill off-screen animations; call **ScrollTrigger.refresh()** when layout changes, debounced when possible.

## Do Not

- ❌ Animate **width**/ **height**/ **top**/ **left** for movement when **x**/ **y**/ **scale** can achieve the same look.
- ❌ Set **will-change** or **force3D** on every element “just in case”; use for elements that are actually animating.
- ❌ Create hundreds of overlapping tweens or ScrollTriggers without testing on low-end devices.
- ❌ Ignore cleanup; stray tweens and ScrollTriggers keep running and can hurt performance and correctness.

## 🚨 Edge-Case & Failure Mode Matrix

| Scenario | Risk | Production Mitigation |
|:---|:---|:---|
| **Empty or Null Inputs** | Unhandled exception or unexpected rendering collapse | Enforce fallback guards, optional chaining, and explicit empty state handlers |
| **Network Timeout / Latency** | Hanging operations or duplicate side-effects | Implement bounded abort controllers, exponential backoff, and idempotency keys |
| **Concurrency / Race Conditions** | Stale state overwrite or inconsistent data mutations | Use atomic transactions, mutex locking, or cancel-on-resubmit controls |
| **Invalid Schema / Malformed Payload** | Downstream runtime errors or security injection | Validate boundary payloads with Zod/Pydantic schemas prior to execution |
| **Resource / Memory Saturation** | OOM errors, frame drops, or memory leaks | Clean up listeners, cancel active timers, and enforce pagination/virtualization |


## 🤖 LLM-Specific Traps Table

| Anti-Pattern | What AI Commonly Does Wrong | What Is Actually Correct |
|:---|:---|:---|
| **The Instant Pop Trap** | Conditionally unmounting elements without animated interpolation | Use AnimatePresence or coordinate morphs with continuous geometry |
| **Layout Thrashing** | Animating width, height, top, or left inside animation loops | Animate composite-only transform (translate3d, scale) and opacity |
| **Sluggish Duration** | Setting micro-interaction transitions to 600ms+ causing interface lag | Cap interactive feedback at 160ms–240ms with snappy ease-out curves |


## 🏛️ Tribunal Verification & Guardrails

**Active Reviewers:** `frontend-reviewer` · `motion-reviewer` · `ui-ux-auditor`
**Slash Command:** `/review` or `/tribunal-full`

### 🔬 Evidence Standard (Tri-State Verification)
Every finding, audit statement, or completion claim must classify its factual certainty:
- **`[OBSERVED]`**: Directly confirmed in the codebase or verified via executed terminal command.
- **`[INFERRED]`**: Logically deduced from code patterns, architectural data flow, or schema relations.
- **`[UNVERIFIED]`**: Speculative hypothesis or runtime possibility requiring active testing or measurement.

### ✅ Pre-Flight Self-Audit Checklist
```
✅ Does animation maintain 60fps/120fps using transform (translate3d, scale) and opacity?
✅ Is optical mass conserved across state interpolations without volume collapse?
✅ Is duration capped within micro-interaction budgets (150ms–280ms)?
✅ Is prefers-reduced-motion respected with graceful instant fallbacks?
✅ Did I prevent layout thrashing and continuous geometry mutations?
```

### 🛑 Verification-Before-Completion (VBC) Protocol
**CRITICAL:** You must follow a strict "evidence-based closeout" state machine.
- ❌ **Forbidden:** Declaring a task complete because the output "looks correct."
- ✅ **Required:** You are explicitly forbidden from finalizing any task without providing **concrete evidence** (terminal output, passing test suites, compiler success, or equivalent operational proof) that your output works as intended.