optimize-web-animations

A workflow for finding performance problems in animated webpages and fixing their underlying work. It examines browser animation, timers, event listeners, canvases, WebGL, and cleanup when pages change or close.

In plain words
What is it for?
Use it to profile and improve CSS animations, canvas or WebGL loops, marquees, loading effects, GSAP or Three.js scenes, and long-session performance.
Why use it?
Animations can keep running when they are offscreen or after a page is removed, wasting processing and memory. Measuring the real page helps identify those cases before editing.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/devinilabs/pro-skill/optimize-web-animations
Any agent
npx skills add devinilabs/pro-skill --skill optimize-web-animations
Clone the repo
git clone --depth 1 https://github.com/devinilabs/pro-skill

Made for: Claude Code, Codex.

Per session 126 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,753 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00126 $0.01753
Opus 5 $0.00063 $0.00877
Sonnet 5 $0.00025 $0.00351
Haiku 4.5 $0.00013 $0.00175

Measured 3d ago against content hash 37a8f512bb22, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

optimize-web-animations scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to optimize-web-animations — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

agent-skills/codex/optimize-web-animations/SKILL.md · 128 lines

How it starts

The opening of the file, as written. The whole thing — 128 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Optimize Web Animations

Core Rule

Measure the real page before editing. The goal is not to remove motion; it is to make offscreen work stop, visible motion resume correctly, and route/unmount cleanup release long-lived resources.

Use Codex Browser when available, especially for localhost pages. Do not use Chrome unless the user explicitly asks for it.

Workflow

  1. Inspect repo context.

    • Read AGENTS.md or local instructions.
    • Run git status --short early.
    • Find page components, animation hooks, CSS keyframes, requestAnimationFrame, setInterval, setTimeout, canvas/WebGL/physics components, media elements, GSAP timelines/tweens, and existing visibility utilities.
    • Search effect cleanup for event listeners, observers, RAF loops, intervals, timers, external scripts, media streams, WebGL textures/materials/geometries/renderers, and async work that can complete after unmount.
    • If the worktree is dirty, plan narrow staging from the start.
  2. Capture a baseline in the browser.

    • Open the exact route the user named.
    • Profile at top, mid-page, footer/lower content, and one mobile viewport when layout could differ.
    • Count CSS animations by computed animationName, animationPlayState, and visibility. Include ::before and ::after.
    • Inspect canvases/WebGL elements separately; CSS profiling does not prove RAF loops have stopped.
    • Record which animation names are running offscreen and the DOM owners responsible.
    • For memory/leak asks, also record element/canvas/image/iframe counts, exposed JS heap metrics when available, an idle sample after 10-30 seconds, and a short route-cycle sample. If heap APIs return null or the Browser sandbox blocks monkey-patching, say so and rely on stable observable counts plus source audit.
    • Keep stress tests bounded. A Browser tab crash during profiling is evidence of overload, but do not over-attribute the cause unless reproduced by a minimal test.
    • See references/browser-profiling.md for a reusable Codex Browser evaluator.

Read the full file on GitHub · 128 lines

Files

What ships with it

7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 128 lines · 126 tokens per session scan A 37a8f512bb22

Subscribe to this mod's changes

optimize-web-animations is a skill published in the GitHub repository devinilabs/pro-skill (19 stars, last pushed 20d ago), licensed MIT. It adds 126 tokens to every session and 1,753 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to optimize-web-animations, differing in 0 lines, and is treated as a copy.

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