packages/skills-catalog/skills/(performance)/perf-astro/SKILL.md
Astro-specific performance optimizations for 95+ Lighthouse scores. Covers critical CSS inlining, compression, font loading, and LCP optimization. Use when optimizing Astro site performance, improving Astro Lighthouse scores, or configuring astro-critters. Do NOT use for non-Astro sites (use perf-web-optimization or core-web-vitals) or running Lighthouse audits (use perf-lighthouse).
npx skillsauth add tech-leads-club/agent-skills perf-astroInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
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Astro-specific optimizations for 95+ Lighthouse scores.
npm install astro-critters @playform/compress
// astro.config.mjs
import { defineConfig } from 'astro/config'
import critters from 'astro-critters'
import compress from '@playform/compress'
export default defineConfig({
integrations: [
critters(),
compress({
CSS: true,
HTML: true,
JavaScript: true,
Image: false,
SVG: false,
}),
],
})
Automatically extracts and inlines critical CSS. No configuration needed.
What it does:
Build output shows what it inlined:
Inlined 40.70 kB (80% of original 50.50 kB) of _astro/index.xxx.css.
Minifies HTML, CSS, and JavaScript in the final build.
Options:
compress({
CSS: true, // Minify CSS
HTML: true, // Minify HTML
JavaScript: true, // Minify JS
Image: false, // Skip if using external image optimization
SVG: false, // Skip if SVGs are already optimized
})
Structure your Layout.astro for performance:
---
import '../styles/global.css'
---
<!doctype html>
<html lang="pt-BR">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<!-- Font fallback (prevents FOIT) -->
<style>
@font-face {
font-family: 'Inter';
font-display: swap;
src: local('Inter');
}
</style>
<!-- Non-blocking Google Fonts -->
<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link
rel="stylesheet"
href="https://fonts.googleapis.com/css2?family=Inter:wght@400;600;700&display=swap"
media="print"
onload="this.media='all'"
/>
<noscript>
<link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Inter:wght@400;600;700&display=swap">
</noscript>
<!-- Preload LCP images -->
<link rel="preload" as="image" href="/hero.png" fetchpriority="high">
<title>{title}</title>
<!-- Defer third-party scripts -->
<script>
let loaded = false;
function loadAnalytics() {
if (loaded) return;
loaded = true;
// Load GTM, analytics, etc.
}
['scroll', 'click', 'touchstart'].forEach(e => {
document.addEventListener(e, loadAnalytics, { once: true, passive: true });
});
setTimeout(loadAnalytics, 5000);
</script>
</head>
<body>
<slot />
</body>
</html>
npx lighthouse https://your-site.com --preset=perf --form-factor=mobile
See also:
astro-critters installed and configured@playform/compress installed and configuredmedia="print" onload pattern<head>development
Apply modern web development best practices for security, compatibility, and code quality. Use when asked to "apply best practices", "security audit", "modernize code", "code quality review", or "check for vulnerabilities". Do NOT use for accessibility (use web-accessibility), SEO (use seo), performance (use core-web-vitals), or comprehensive multi-area audits (use web-quality-audit).
tools
Complete browser automation with Playwright. Auto-detects dev servers, writes clean test scripts to /tmp. Test pages, fill forms, take screenshots, check responsive design, validate UX, test login flows, check links, automate any browser task. Use when user wants to test websites, automate browser interactions, validate web functionality, or perform any browser-based testing. Do NOT use for quick page debugging or network inspection (use chrome-devtools instead).
development
Configure, explore, and optimize Nx monorepo workspaces. Use when setting up Nx, exploring workspace structure, configuring project boundaries, analyzing affected projects, optimizing build caching, or implementing CI/CD with affected commands. Keywords — nx, monorepo, workspace, projects, targets, affected. Do NOT use for running tasks (use nx-run-tasks) or code generation with generators (use nx-generate).
development
Execute build, test, lint, serve, and other tasks in an Nx workspace using single runs, run-many, and affected commands. Use when user says "run tests", "build my app", "lint affected", "serve the project", "run all tasks", or "nx affected". Do NOT use for code generation (use nx-generate) or workspace configuration (use nx-workspace).