benchmark

name	benchmark
description	Performance baseline and regression detection -- page performance, API latency, build times, and before/after comparison.
origin	ECC

Benchmark -- Performance Baseline and Regression Detection

Measure and compare performance metrics to detect regressions.

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

Modes

Mode 1: Page Performance

Measures real browser metrics: LCP, CLS, INP, FCP, TTFB, total page weight, JS bundle size, CSS size, image weight, network request count.

Mode 2: API Performance

Benchmarks API endpoints: hit each endpoint 100 times, measure p50/p95/p99 latency, track response size, test under 10 concurrent requests.

Mode 3: Build Performance

Measures development feedback loop: cold build time, HMR time, test suite duration, TypeScript check time, lint time, Docker build time.

Mode 4: Before/After Comparison

/benchmark baseline    # saves current metrics
# ... make changes ...
/benchmark compare     # compares against baseline

Output:

Metric	Before	After	Delta	Verdict
LCP	1.2s	1.4s	+200ms	WARN
Bundle	180KB	175KB	-5KB	BETTER
Build	12s	14s	+2s	WARN

Storage

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