/animation-jank-qa

name: animation-jank-qa
description: "Diagnose a concrete rendered hitch or stutter."

Animation Jank QA

Use this skill for symptom-led runtime diagnosis. Start from a reproducible jank case and determine whether it comes from main-thread work, layout/paint, asset pressure, scroll coupling, competing animation systems, or lifecycle cleanup.

Workflow

1. Reproduce the exact affected route, interaction, viewport, and device class. 2. Read [Animation Jank QA Guide](references/animation-jank-qa-guide.md) for relevant diagnosis and retesting steps. 3. Run the narrowest meaningful trace or rendered check for the symptom; inspect frame timing, long tasks, forced layout, paint/compositing, asset decode, observers, timers, and RAF loops as applicable. 4. Fix issues when they are in scope; otherwise record exact evidence and remaining risk. 5. Retest the original symptom and summarize commands, URLs, traces/screenshots, changed files, and what was not tested.

Always Protect

• Inspect the framework, motion stack, affected media, component lifecycle, and available browser/performance tooling before changing code.
• Do not claim something was tested unless it was actually tested; report exact commands, URLs, screenshots, viewports, failures, skipped checks, and remaining risk.
• Reproduce and retest rendered output on the affected route and supported viewport/device classes; inspect console, trace, network and layout evidence relevant to that symptom.
• Respect accessibility, performance, reduced-motion, and no-JavaScript/no-WebGL/no-autoplay fallbacks where relevant.
• Keep secrets out of code, logs, screenshots, summaries, widgets, and committed files.
• Prefer project-local tooling and existing scripts before adding dependencies. Explain any new dependency before installing it.
• End with a concise handoff: changed files, commands run, checks passed, checks not run, deployment URL if any, and next risks.