Webperf

Web performance measurement and debugging toolkit. Use when the user asks about web performance, wants to audit a page, or says "analyze performance", "debug...

WebPerf Snippets Toolkit

A collection of 47 JavaScript snippets for measuring and debugging web performance in Chrome DevTools. Each snippet runs in the browser console and outputs structured, color-coded results.

Skills by Category

Skill	Snippets	Use when
webperf-core-web-vitals	7	Intelligent Core Web Vitals analysis with automated workflows and decision trees
webperf-loading	28	Intelligent loading performance analysis with automated workflows for TTFB investigation (DNS/connection/server breakdown), render-blocking detection, script performance deep dive (first vs third-party attribution), font optimization, and resource hints validation
webperf-interaction	8	Intelligent interaction performance analysis with automated workflows for INP debugging, scroll jank investigation, and main thread blocking
webperf-media	3	Intelligent media optimization with automated workflows for images, videos, and SVGs
webperf-resources	1	Intelligent network quality analysis with adaptive loading strategies

Quick Reference

User says	Skill to use
"debug LCP", "slow LCP", "largest contentful paint"	webperf-core-web-vitals
"check CLS", "layout shifts", "visual stability"	webperf-core-web-vitals
"INP", "interaction latency", "responsiveness"	webperf-core-web-vitals
"TTFB", "slow server", "time to first byte"	webperf-loading
"FCP", "first contentful paint", "render blocking"	webperf-loading
"font loading", "script loading", "resource hints", "service worker"	webperf-loading
"jank", "scroll performance", "long tasks", "animation frames", "INP debug"	webperf-interaction
"image audit", "lazy loading", "image optimization", "video audit"	webperf-media
"network quality", "bandwidth", "connection type", "save-data"	webperf-resources

Workflow

1. Identify the relevant skill based on the user's question (use Quick Reference above)
2. Load the skill's skill.md to see available snippets and thresholds
3. Execute with Chrome DevTools MCP:
   • mcp__chrome-devtools__navigate_page → navigate to target URL
   • mcp__chrome-devtools__evaluate_script → run the snippet
   • mcp__chrome-devtools__get_console_message → read results
4. Interpret results using the thresholds defined in the skill
5. Provide actionable recommendations based on findings