web-perf
Measures Core Web Vitals and identifies render-blocking resources, network chains, layout shifts, and caching issues.
What it does
- Be assertive: Verify claims by checking network requests, DOM, or codebase—then state findings definitively.
- Verify before recommending: Confirm something is unused before suggesting removal.
- Quantify impact: Use estimated savings from insights. Don't prioritize changes with 0ms impact.
- Skip non-issues: If render-blocking resources have 0ms estimated impact, note but don't recommend action.
- Be specific: Say "compress hero.png (450KB) to WebP" not "optimize images".
- Prioritize ruthlessly: A site with 200ms LCP and 0 CLS is already excellent—say so.
- [ ] Phase 1: Performance trace (navigate + record)
Requirements & configuration
- Key thresholds (good/needs-improvement/poor):
- 1. Core Web Vitals Summary - Table with metric, value, and rating (good/needs-improvement/poor)
Derived from the skill's own SKILL.md documentation · extracted 2026-07-23
Measures Core Web Vitals and identifies render-blocking resources, network chains, layout shifts, and caching issues.
Source
Repository: https://github.com/cloudflare/skills
web-perf FAQ
What does the web-perf skill do?
Analyzes web performance using Chrome DevTools MCP. Measures Core Web Vitals (LCP, INP, CLS) and supplementary metrics (FCP, TBT, Speed Index), identifies render-blocking resources, network dependency chains, layout shifts, caching issues, and accessibility gaps. Use when asked to audit, profile, debug, or optimize page load performance, Lighthouse scores, or site speed. Biases towards retrieval from current documentation over pre-trained knowledge. Be assertive: Verify claims by checking network requests, DOM, or codebase—then state findings definitively. Verify before recommending: Confirm something is unused before suggesting removal.
What does web-perf require?
Key thresholds (good/needs-improvement/poor): 1. Core Web Vitals Summary - Table with metric, value, and rating (good/needs-improvement/poor)
How do I install web-perf?
Run: npx -y skills add https://github.com/cloudflare/skills --skill web-perf --agent claude-code — the source lives at github.com/cloudflare/skills.
Maintain web-perf?
Let people know it's listed here — add the badge (live metrics, light/dark aware) or a plain link to your README or docs.
[](https://getagentictools.com/skills/cloudflare-skills-web-perf?ref=badge) npx agentictools info skills/cloudflare-skills-web-perf The second line is the CLI lookup for this page — handy in READMEs and docs.
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