mcpbeat

Performance

plugin87/performance

Optimize UI performance against Core Web Vitals — LCP, INP, CLS — with loading/code-split strategy, layout-shift prevention, and animation performance rules. Use when the user wants to improve speed, fix jank or layout shift, hit Web Vitals budgets, or make a UI feel fast on low-end devices.

416 tokens
context cost
the whole folder, loaded on every use
1
files
instructions only
0
copies elsewhere
how many repositories repackaged it
482
stars on the repo
on the repository, not the skill itself

Install

one command, takes just this skill from the repository 
npx skills add https://github.com/plugin87/ux-ui-agent-skills --skill performance

The instruction itself

3 sections, as written by the author

Skill: Performance

Make the UI fast and stable. Treat performance as an accessibility concern — slow/janky UIs fail low-end devices first.

Steps

  • Read workflows/performance.md (Core Web Vitals targets, loading strategy, layout-shift, animation perf, design-system runtime cost).
  • Diagnose against budgets: LCP ≤ 2.5s, INP ≤ 200ms, CLS ≤ 0.1. Measure on a mid-tier mobile profile (throttle slow 4G + 4× CPU).
  • Loading: render above-fold first (SSR/Server Components), code-split by route + heavy widget, lazy-load below-fold/behind-interaction (Astro islands / Qwik), preload one critical font weight, modern responsive images.
  • Kill layout shift: size skeletons to final dimensions, reserve media space via aspect-ratio (tokens/sizing.json), never inject content above existing.
  • Animation: only transform/opacity, will-change sparingly, 100–300ms (tokens/motion.json), honor prefers-reduced-motion. Prefer CSS state styling over JS for low INP; tree-shake/per-component imports.

Verification (definition of done)

  • Lighthouse / field data meets LCP ≤ 2.5s, INP ≤ 200ms, CLS ≤ 0.1 on mid-tier mobile.
  • First interaction stays responsive under slow-4G + 4× CPU throttle.
  • Skeletons + media reserve space (zero CLS on load); no non-compositor animation in loops.

How to use it

Copy the folder

Take plugin87/performance from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.