Use this skill to measure performance baselines, detect regressions before/after PRs, and compare stack alternatives.

Benchmark — Performance Baseline & Regression Detection When to Use Before and after a PR to measure performance impact Setting up performance baselines for a project When users report "it feels slow" Before a launch — ensure you meet performance targets Comparing your stack against alternatives How It Works Mode 1: Page Performance Measures real browser metrics via browser MCP: Mode 2: API Performance Benchmarks API endpoints: Mode 3: Build Performance Measures development feedback loop: Mode 4: Before/After Comparison Run before and after a change to measure impact: Output: Output Stores baselines in .ecc/benchmarks/ as JSON. Git tracked so the team shares baselines. Integration CI: run /benchmark compare on every PR Pair with /canary watch for post deploy monitoring Pair with /browser qa for full pre ship checklist