Deploy Safety Skill

Safe deployment patterns for modern web applications.

When to Apply

• User mentions "deploy", "push to production", "ship it"
• Before any git push to main/production
• When discussing deployment targets
• Changes span frontend and backend

Pre-Deployment Checklist

1. Correct Branch

git branch --show-current
# Confirm this is the intended branch

2. What Changed

# Files changed
git diff --name-only origin/main...HEAD

# Frontend vs backend changes
git diff --name-only origin/main...HEAD | grep -E "^src/" | wc -l
git diff --name-only origin/main...HEAD | grep -E "^backend/" | wc -l

3. Clean Working Directory

git status --porcelain
# Should be empty

4. Tests Pass

npm test
npm run build

Deployment Rules

Frontend-Only Changes

If changes are ONLY in src/:

• Push to main, Vercel auto-deploys
• No backend action needed

Backend-Only Changes

If changes are ONLY in backend/:

• Deploy to backend platform
• Verify API contracts unchanged

Mixed Changes (FE + BE)

If changes span both:

• Verify API contracts match
• Deploy backend first (usually)
• Then deploy frontend

Database Migrations

If migrations included:

• Test in staging first
• Have rollback plan ready
• Run migration before code deployment

Vercel Commands

vercel                  # Deploy preview
vercel --prod           # Deploy production
vercel ls               # List deployments
vercel logs [url]       # View logs
vercel env add VAR      # Add env variable
vercel env pull         # Pull env to local

Post-Deployment Verification

# Health check
curl https://your-app.vercel.app/api/health

# Check for errors
# - Browser console
# - Server logs
# - Error tracking (Sentry, etc.)

Rollback

If deployment fails:

1. Vercel/Netlify: Instant rollback via dashboard
2. Backend: git revert and redeploy
3. Database: Run rollback migration

Environment Variables

Verify before deploy:

# Frontend (public)
NEXT_PUBLIC_API_URL=https://api.example.com
NEXT_PUBLIC_SUPABASE_URL=...

# Backend (private - never expose)
DATABASE_URL=...
STRIPE_SECRET_KEY=...