Build Performance

Severity: Recommended

Builds should be fast: under 3 minutes for clean builds, under 30 seconds with caching. Slow builds hurt developer productivity and CI costs.

Check automatically:

1. Check for build caching configuration:

# Turborepo (monorepo caching)
ls -la turbo.json 2>/dev/null
grep -E "\"turbo\"" package.json 2>/dev/null

# Nx (monorepo caching)
ls -la nx.json 2>/dev/null
grep -E "\"nx\"" package.json 2>/dev/null

# Vite/esbuild/swc (fast by design)
grep -E "\"vite\"|\"esbuild\"|\"@swc\"" package.json 2>/dev/null

# Webpack caching configuration
grep -rE "cache.*filesystem|cache.*type.*filesystem" webpack.config.* 2>/dev/null

# Next.js (has built-in caching)
grep -E "\"next\":" package.json 2>/dev/null

2. Check CI caching:

# GitHub Actions cache
grep -rE "actions/cache|cache:" .github/workflows/ 2>/dev/null

# Node modules / pnpm store caching
grep -rE "node_modules|pnpm-store|\.npm|\.pnpm" .github/workflows/ 2>/dev/null

# Build output caching
grep -rE "\.next|dist|build|\.turbo" .github/workflows/ 2>/dev/null

3. Check build scripts:

# What does the build command do?
grep -E "\"build\":" package.json 2>/dev/null

# Check for build optimization flags
grep -rE "NODE_ENV=production|--minify|--sourcemap" package.json Makefile 2>/dev/null

4. Check recent CI build times (if GitHub Actions):

# Get recent workflow runs with duration
gh run list --limit 10 --json databaseId,displayTitle,conclusion,createdAt,updatedAt 2>/dev/null

Measure actual build times (use subagent):

• Run clean build (delete node_modules/.next/.turbo/dist first)
• Time the build: time pnpm build or equivalent
• Run cached build (second run without cleaning)
• Time again and compare

Benchmarks:

Metric	Good	Acceptable	Needs Work
Clean build	< 2 min	< 3 min	> 5 min
Cached build	< 15 sec	< 30 sec	> 1 min
CI build	< 3 min	< 5 min	> 10 min

Ask user:

• "How long does a typical build take?"
• "Is build caching configured?"
• "Are developers waiting on builds frequently?"

Cross-reference with:

• DEPLOY-003 (CI build performance - same concept, deployment context)
• Section 2 (Dependencies - fewer deps = faster builds)
• DEP-007 (Turborepo for monorepos - caching solution)

Pass criteria:

• Clean build completes in < 3 minutes
• Cached/incremental build completes in < 30 seconds
• Build caching is configured (local and/or CI)
• No unnecessary rebuilds of unchanged code

Partial pass:

• Build times acceptable but no caching configured
• Caching configured but not optimized (cache misses common)
• Local builds fast but CI builds slow

Fail criteria:

• Clean build > 5 minutes
• No caching configured (every build is full rebuild)
• Cached build still takes minutes
• Developers avoid running builds due to slowness
• CI times consistently > 10 minutes

Evidence to capture:

• Measured clean build time
• Measured cached build time
• Caching tools in use (Turbo, Nx, Webpack cache, etc.)
• CI build times (from recent runs)
• Any identified bottlenecks

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