Measure performance baselines and detect regressions across browser Core Web Vitals (LCP, INP, CLS, page weight), API endpoint latency percentiles, and build/test feedback times, with before/after comparison stored in git-tracked .ecc/benchmarks JSON. Use when checking page speed, responding to 'it feels slow' reports, verifying launch performance targets, or comparing stack alternatives.
Install
npx skills add affaan-m/ECC --skill benchmarknpx skills add affaan-m/ECC --skill benchmark -a claude-code -gnpx skills add affaan-m/ECC --skill benchmark -a codex -ggemini skills install https://github.com/affaan-m/ECC.git --path docs/ja-JP/skills/benchmarkgh skill install affaan-m/ECC benchmarkgit clone --depth 1 https://github.com/affaan-m/ECC /tmp/affaan-m__ECC
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/affaan-m__ECC/docs/ja-JP/skills/benchmark ~/.claude/skills/benchmark # Claude Code
cp -R /tmp/affaan-m__ECC/docs/ja-JP/skills/benchmark ~/.agents/skills/benchmark # Codex, Cursor, Gemini CLI, Copilot, OpenCode