benchmark

Name: benchmark
Author: affaan-m

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

INSTALLATION

npx skills add https://github.com/affaan-m/everything-claude-code --skill benchmark

Run in your project or agent environment. Adjust flags if your CLI version differs.

SKILL.md

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:

1. Navigate to each target URL

2. Measure Core Web Vitals:

   - LCP (Largest Contentful Paint) — target < 2.5s

   - CLS (Cumulative Layout Shift) — target < 0.1

   - INP (Interaction to Next Paint) — target < 200ms

   - FCP (First Contentful Paint) — target < 1.8s

   - TTFB (Time to First Byte) — target < 800ms

3. Measure resource sizes:

   - Total page weight (target < 1MB)

   - JS bundle size (target < 200KB gzipped)

   - CSS size

   - Image weight

   - Third-party script weight

4. Count network requests

5. Check for render-blocking resources

Mode 2: API Performance

Benchmarks API endpoints:

1. Hit each endpoint 100 times

2. Measure: p50, p95, p99 latency

3. Track: response size, status codes

4. Test under load: 10 concurrent requests

5. Compare against SLA targets

Mode 3: Build Performance

Measures development feedback loop:

1. Cold build time

2. Hot reload time (HMR)

3. Test suite duration

4. TypeScript check time

5. Lint time

6. Docker build time

Mode 4: Before/After Comparison

Run before and after a change to measure impact:

/benchmark baseline    # saves current metrics

# ... make changes ...

/benchmark compare     # compares against baseline

Output:

| Metric | Before | After | Delta | Verdict |

|--------|--------|-------|-------|---------|

| LCP | 1.2s | 1.4s | +200ms | WARNING: WARN |

| Bundle | 180KB | 175KB | -5KB | ✓ BETTER |

| Build | 12s | 14s | +2s | WARNING: WARN |

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