Analyzes web performance using Chrome DevTools MCP. Measures Core Web Vitals (LCP, INP, CLS) and supplementary metrics (FCP, TBT, Speed Index), identifies…
Measures Core Web Vitals and identifies render-blocking resources, network chains, layout shifts, and caching issues. Analyzes performance traces using Chrome DevTools MCP to extract FCP, LCP, TBT, CLS, Speed Index, and TTFB with detailed breakdowns Identifies render-blocking CSS/JS, network dependency chains, missing preloads, and caching header gaps through network request inspection Detects layout shift culprits (images without dimensions, injected content, font swaps) and accessibility gaps via DOM snapshots Requires chrome-devtools MCP server configured; provides checklist-driven audit workflow across performance, network, and accessibility phases Prioritizes findings by estimated impact and skips non-issues; biases toward live documentation over pre-trained thresholds Web Performance Audit Your knowledge of web performance metrics, thresholds, and tooling APIs may be outdated. Prefer retrieval over pre-training when citing specific numbers or recommendations. Retrieval Sources Source How to retrieve Use for web.dev https://web.dev/articles/vitals Core Web Vitals thresholds, definitions Chrome DevTools docs https://developer.chrome.com/docs/devtools/performance Tooling APIs, trace analysis Lighthouse scoring https://developer.chrome.com/docs/lighthouse/performance/performance-scoring Score weights, metric thresholds FIRST: Verify MCP Tools Available Run this before starting. Try calling navigate_page or performance_start_trace. If unavailable, STOP—the chrome-devtools MCP server isn't configured. Ask the user to add this to their MCP config:
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