Performance Audit

Workflow

1. Detect build tool from package.json (vite, webpack, next, rollup)

2. Run the production build via the project's task runner (auto-detect from package.json).

3. Analyze the build output — non-interactive only. Never launch a browser or a long-running server in an audit; those hang an automated run. Prefer, in order:

   • Measure the emitted files directly: for each file in the output dir (e.g. dist/assets/*.js), report raw + gzipped size — gzip -c <file> | wc -c. This always works and needs no extra tooling.
   • Per-module breakdown, as a static artifact (not a server), written under $TMPDIR (else /tmp) and never the working tree, where the next commit would sweep it in. Print the path:
     • Vite/Rollup: npx source-map-explorer 'dist/assets/*.js', or add rollup-plugin-visualizer configured to emit JSON/HTML to a file
     • webpack/Next.js: npx webpack-bundle-analyzer -m static -r "${TMPDIR:-/tmp}/report.html" <stats-file> (writes a file; do not use the default server mode)
   • npx vite-bundle-visualizer opens a browser and blocks — only suggest it to the user for manual exploration; do not run it here.

4. Check package.json for known heavy packages

5. Check the source for the Core Web Vitals risks below. Detect the framework first; recommend only its idioms.

6. Report findings: size impact for the bundle, potential impact for source risks

Compare against standard industry thresholds; report gzipped sizes.