web-performance-audit
Web performance audits with Core Web Vitals, bottleneck identification, optimization recommendations. Use for page load times, performance reviews, UX optimization, or encountering LCP, FID, CLS issues, resource blocking, render delays.
- Installs
- 528
- Last 24h
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Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/secondsky/claude-skills --skill web-performance-audit- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads web-performance-audit automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
Web Performance Audit
Conduct comprehensive performance audits and implement optimizations.
Core Web Vitals Targets
| Metric | Good | Needs Improvement | Poor |
|---|---|---|---|
| LCP (Largest Contentful Paint) | <2.5s | 2.5-4s | >4s |
| FID (First Input Delay) | <100ms | 100-300ms | >300ms |
| CLS (Cumulative Layout Shift) | <0.1 | 0.1-0.25 | >0.25 |
| INP (Interaction to Next Paint) | <200ms | 200-500ms | >500ms |
Performance Measurement
// Using web-vitals library
import { getCLS, getFID, getLCP, getTTFB } from 'web-vitals';
function sendToAnalytics({ name, value, id }) {
console.log({ name, value, id });
}
getCLS(sendToAnalytics);
getFID(sendToAnalytics);
getLCP(sendToAnalytics);
getTTFB(sendToAnalytics);
Lighthouse Automation
const lighthouse = require('lighthouse');
const chromeLauncher = require('chrome-launcher');
async function runAudit(url) {
const chrome = await chromeLauncher.launch({ chromeFlags: ['--headless'] });
const result = await lighthouse(url, {
port: chrome.port,
onlyCategories: ['performance']
});
await chrome.kill();
return result.lhr;
}
Optimization Strategies
Quick Wins (1-2 days)
- Enable gzip/brotli compression
- Minify CSS/JS
- Defer non-critical scripts
- Optimize images (WebP, lazy loading)
Medium Effort (1-2 weeks)
- Implement code splitting
- Add service worker caching
- Preload critical resources
- Eliminate render-blocking resources
Long-term (1-3 months)
- Architecture improvements
- CDN optimization
- Database query optimization
Performance Budget
{
"timings": [
{ "metric": "first-contentful-paint", "budget": 1500 },
{ "metric": "largest-contentful-paint", "budget": 2500 }
],
"resourceSizes": [
{ "resourceType": "script", "budget": 150 },
{ "resourceType": "image", "budget": 300 }
]
}
Audit Checklist
- Measure baseline Core Web Vitals
- Run Lighthouse audit (mobile & desktop)
- Analyze real user metrics (RUM)
- Identify largest contentful element
- Check for layout shifts
- Review JavaScript bundle size
- Test on slow 3G connection
- Set performance budget
- Configure monitoring alerts
FAQ
What does the web-performance-audit skill do?
Web performance audits with Core Web Vitals, bottleneck identification, optimization recommendations. Use for page load times, performance reviews, UX optimization, or encountering LCP, FID, CLS issues, resource blocking, render delays.
How do I install web-performance-audit?
Run npx skills add https://github.com/secondsky/claude-skills --skill web-performance-audit in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/web-performance-audit/ (personal) or .claude/skills/web-performance-audit/ (project).
Which AI agents can use web-performance-audit?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is web-performance-audit safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains web-performance-audit?
It is published by secondsky in secondsky/claude-skills. It has 528 recorded installs.
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