Perf audit
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.From its SKILL.md
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.
2 things 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.
- runs commandsInstructs the agent to run 3 commands, including `gzip -c <file> | wc -c` and 2 more.
SKILL.md
2.1 KB, 434 tokens by cl100k_base, 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
What ships with it
Read from the repository
Just SKILL.md. No reference files, no scripts.
Gives 0 of the 12 instructions most audit compliance skills give in 434 tokens
Counted across 960 of the 1,589 authors here whose files we hold, read 2026-09-06
- Read product marketing context before asking questionsin 29 of 960, across 11 files
- Rank findings by severityin 29 of 960, across 22 files
- Generate audit reportin 22 of 960
- Run the audit scriptin 20 of 960, across 19 files
- Generate a prioritized action plan reportin 19 of 960, across 11 files
- Ensure one H1 per pagein 15 of 960, across 5 files
- Ensure sitemap exists and is accessiblein 14 of 960, across 4 files
- Verify alt text on all imagesin 12 of 960, across 3 files
- Determine the audit scope before startingin 12 of 960, across 4 files
- Verify important pages allowed in robots.txtin 11 of 960, across 2 files
- Detect business type from homepage signalsin 11 of 960, across 7 files
- Delegate specialized tasks to subagentsin 11 of 960, across 7 files
Said here and by no other author read
- Detect build tool from package.json
- Run the production build via task runner
- Measure emitted files directly
- Check package.json for known heavy packages
- Report findings with size impact
- Report gzipped sizes
Grouped from the skills themselves: near-identical wordings counted once, and counted by distinct author, so one author publishing three of these counts once. Length counted with cl100k_base; the agent that loads this file may tokenize it differently.