Last commit on October 16, 2026·Created on May 17, 2022
nucliweb/webperf-snippets
“Tested JavaScript snippets that measure and debug web performance. Your AI agent runs them for you, or you run them yourself in DevTools: the same code every time.”
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Tested JavaScript snippets that measure and debug web performance. Your AI agent runs them for you, or you run them yourself in DevTools: the same code every time.
WHO IT'S FOR
Frontend engineers
debug Core Web Vitals and layout shifts
Web performance engineers
analyze interaction latency and main thread blocking
AI agent / automation builders
integrate automated web performance debugging workflows
Compatible AgentsThe repository documents support for these agents. The skills may also work with other agents that can load SKILL.md files, but they may need some setup or small changes.
Configure Chrome DevTools MCP, or install the documented CLI with Playwright and Chromium.
Use webperf-core-web-vitals to measure Largest Contentful Paint on <url> with LCP.js. Report the returned value, rating, and any reported issues. If measurement is unsupported or fails, explain the returned error.
Configure Chrome DevTools MCP, or install the documented CLI with Playwright and Chromium.
Use webperf-media to run Image-Element-Audit.js on <url>. Summarize the image format, lazy-loading, sizing, and fetchpriority findings, and identify the most useful fixes supported by the results.
Configure Chrome DevTools MCP, or install the documented CLI with Playwright and Chromium.
Use webperf-resources to run Network-Bandwidth-Connection-Quality.js on <url>. Summarize the reported effective connection type, RTT, downlink, and save-data mode. Explain any unsupported measurements using the returned result.
Claude
Cursor
Gemini CLI
OpenCode