Perf audit
My personal SDLC toolbelt for AI coding agents — PRD to ship.
npx -y skills add helderberto/agent-skills --skill perf-auditAssembled from the repository path, not quoted from the project. Check it against their README if it does not work.
One thing to look at
- 12 stars12 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.
What its author says it does
Copied from the file, not written here
Audit frontend bundle size and performance. Use when user asks to "audit performance", "/perf-audit", "analyze bundle", "check bundle size", or wants to find performance bottlenecks. Don't use for backend performance, database query optimization, or projects without a frontend build step.
SKILL.md
2.1 KB, as published. Nobody here has run it
Performance Audit
Workflow
-
Detect build tool from
package.json(vite, webpack, next, rollup) -
Run the production build via the project's task runner (auto-detect from package.json).
-
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):
- Vite/Rollup:
npx source-map-explorer 'dist/assets/*.js', or addrollup-plugin-visualizerconfigured to emit JSON/HTML to a file - webpack/Next.js:
npx webpack-bundle-analyzer -m static -r report.html <stats-file>(writes a file; do not use the default server mode)
- Vite/Rollup:
npx vite-bundle-visualizeropens a browser and blocks — only suggest it to the user for manual exploration; do not run it here.
- Measure the emitted files directly: for each file in the output dir (e.g.
-
Check
package.jsonfor known heavy packages -
Report findings with size impact
Compare against standard industry thresholds; report gzipped sizes.
Output format
- Bundle summary: total size / gzipped size vs budget
- Large chunks: name + size + % of total
- Heavy deps: package + size + lighter alternative
- Quick wins: sorted by estimated savings
Rules
- Report gzipped sizes (what the browser downloads)
- Never auto-change dependencies -- report and suggest only
Error Handling
- Build fails -- report the error and stop; fix build issues before auditing
- No build output found -- run production build first
- Build tool unrecognized -- fall back to scanning
package.jsonfor heavy packages only