web-performance-audit
Skill4 starsChanged 27 days agoMITView on GitHub
Use when a website or web app is slow, Lighthouse or PageSpeed scores are low, Core Web Vitals (LCP, INP, CLS) fail, the bundle is too large, pages load or scroll with jank, or React/Next.js/Vue renders feel sluggish.
7 other projects use a version of this.
Adopted by
Most recently taken up by
- Adonis0123/adonis-skillstheir own version, first seen Nov 7, 2026
- wake-engineering/ai-plugintheir own version, first seen Nov 1, 2026
- KMaruthi2002/universal-llm-skillstheir own version, first seen Oct 25, 2026
- davidanthonyn/claude-skillstheir own version, first seen Oct 20, 2026
- ai-moto/web-craft-skillstheir own version, first seen Aug 23, 2026
- omonuj/claude-skillstheir own version, first seen Jul 23, 2026
Other versions7 projects use a version of this.
Word for word · 0
None found.
Edited · 0
None found.
Wrote their own version · 7
- warpdotdev/oz-skills★ 825same name
- Adonis0123/adonis-skills★ 4same name
- wake-engineering/ai-plugin★ 4same name
- KMaruthi2002/universal-llm-skills★ 1same name
- ai-moto/web-craft-skills★ 0same name
- davidanthonyn/claude-skills★ 0same name
- omonuj/claude-skills★ 0same name
How matches are found. Word for word: the exact same text. Edited: shares passages with this file (“99% same” means 99% of its five-word phrases also appear here; 10% or more counts). Their own version: similar meaning, or, weakest, the same name. We can’t tell which project had it first. Projects are counted among the 200 most-starred candidates, and mentions are links to the repository we found, up to 50 per site, so both counts are a floor.
In this repository30 other files it gives its agents.
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- api-design-reviewSkill
- api-test-writerSkill
- architecture-diagramSkill
- bug-debuggerSkill
- bug-report-writerSkill
- changelog-writerSkill
- codebase-onboardingSkill
- code-reviewSkill
- database-schema-designSkill
- dependency-upgradeSkill
- design-handoff-specSkill
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- dockerize-appSkill
- figma-design-compareSkill
- flaky-test-fixerSkill
- git-commit-writerSkill
- github-actions-ciSkill
- playwright-e2e-testsSkill
- prd-writerSkill
- proof-of-done-liteSkill
- readme-writerSkill
- refactor-plannerSkill
- security-auditSkill
- seo-auditSkill
- test-case-generatorSkill
- test-plan-writerSkill
- test-writerSkill
- ux-research-synthesisSkill
- ux-writingSkill
The file
We split this skill into the rules it gives an agent
1 rule. 0 are common, 1 is distinctive, and 0 are very specific to this project.
0
Common
Most of the 7 edited versions we read keep these.
1
Distinctive
This author's own choices. Worth a look.
0
Very specific
Tied to their project's names, files or tools. Probably skip.
- Common
- Distinctive
- Very specific
- Distinctive: line 31
Start with the metric summary (measured or estimated).
“Common” is measured: kept by at least 6 in 10 of the 7 edited versions of this file we could read. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.
Files
Web Performance Audit
Overview
Tie every fix to the metric it moves. Find the few causes that dominate load time and interaction delay, show where they are in the code, and estimate the gain.
Method
- Measure if possible. With a URL: run
npx lighthouse <url> --only-categories=performance --output=json --quietor use PageSpeed Insights. Record LCP, INP (or TBT), CLS and total JS. Without a URL, audit the code and say that numbers are estimates. - Find the LCP element (usually the hero image or heading) and trace what delays it: server time, render-blocking CSS/fonts/scripts, image size and priority.
- Sweep the code with checklist.md: images, fonts, JavaScript weight, third parties, rendering, data fetching, caching.
- Rank by impact on the failing metric, then by effort.
- Report using the contract below.
Targets (75th percentile, mobile)
| Metric | Good | Usual causes when poor |
| LCP | ≤ 2.5 s | Large or lazy-loaded hero image, render-blocking CSS/fonts, slow TTFB, client-side data fetch before render |
| INP | ≤ 200 ms | Long tasks, heavy hydration, expensive re-renders, synchronous work in event handlers |
| CLS | ≤ 0.1 | Images or embeds without size, late-loading fonts, injected banners above content |
| JS (compressed) | < 170 KB on first load | Whole-library imports, no code splitting, duplicated packages |
Output contract
Start with the metric summary (measured or estimated). Then, highest impact first:
### [High | Medium | Low] Title
- Metric: LCP | INP | CLS | TTFB | bundle size
- Where: file:line or resource URL
- Evidence: the code or measurement that shows the problem
- Fix: the exact change (code snippet or config)
- Expected gain: e.g. "LCP −0.8 s", "−120 KB JS"End with Quick wins (under an hour each) and Already good (what you checked that is fine).
Common mistakes
- Lazy-loading the LCP image. It must load eagerly with high priority.
- Recommending generic tips ("minify CSS") that the build already does.
- Memoizing everything instead of fixing the one component that re-renders a large list.
- Ignoring third-party scripts, which often cost more than the app itself.
- Claiming exact gains without measurement; label estimates.
Made by Wageesha Tripathi · LinkedIn · Email · More skills
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Your trail
Files you open will collect here, so you can find them again.
Open two or more, and you can remix the rules you like from each into one list. Kept in this browser only.
Now do this for your own.
Bring your CLAUDE.md, AGENTS.md or skills. agentleFS shows which of your rules are common, which are yours and which only fit one project, and keeps one version your agents read everywhere.