CI/CD and Automation Overview Automate quality gates so that no change reaches production without passing tests, lint, type checking, and build. CI/CD is the enforcement mechanism for every other skill — it catches what humans and agents miss, and it does so consistently on every single change. Shift Left: Catch problems as early in the pipeline as possible. A bug caught in linting costs minutes; the same bug caught in production costs hours. Move checks upstream — static analysis before tests, tests before staging, staging before production. Faster is Safer: Smaller batches and more frequent releases reduce risk, not increase it. A deployment with 3 changes is easier to debug than one with 30. Frequent releases build confidence in the release process itself. When to Use Setting up a new project's CI pipeline Adding or modifying automated checks Configuring deployment pipelines When a change should trigger automated verification Debugging CI failures The Quality Gate Pipeline Every change goes through these gates before merge: Pull Request Opened │ ▼ ┌─────────────────┐ │ LINT CHECK │ eslint, prettier │ ↓ pass │ │ TYPE CHECK │ tsc --noEmit │ ↓ pass │ │ UNIT TESTS │ jest/vitest │ ↓ pass │ │ BUILD │ npm run build │ ↓ pass │ │ INTEGRATION │ API/DB tests │ ↓ pass │ │ E2E (optional) │ Playwright/Cypress │ ↓ pass │ │ SECURITY AUDIT │ npm audit │ ↓ pass │ │ BUNDLE SIZE │ bundlesize check └─────────────────┘ │ ▼ Ready for review No gate can be skipped. If lint fails, fix lint — don't disable the rule. If a test fails, fix the code — don't skip the test. GitHub Actions Configuration Basic CI Pipeline

.github/workflows/ci.yml

name : CI on : pull_request : branches : [ main ] push : branches : [ main ] jobs : quality : runs-on : ubuntu - latest steps : - uses : actions/checkout@v4 - uses : actions/setup - node@v4 with : node-version : '22' cache : 'npm' - name : Install dependencies run : npm ci - name : Lint run : npm run lint - name : Type check run : npx tsc - - noEmit - name : Test run : npm test - - - - coverage - name : Build run : npm run build - name : Security audit run : npm audit - - audit - level=high With Database Integration Tests integration : runs-on : ubuntu - latest services : postgres : image : postgres : 16 env : POSTGRES_DB : testdb POSTGRES_USER : ci_user POSTGRES_PASSWORD : $ { { secrets.CI_DB_PASSWORD } } ports : - 5432 : 5432 options :

-

- health - cmd pg_isready - - health - interval 10s - - health - timeout 5s - - health - retries 5 steps : - uses : actions/checkout@v4 - uses : actions/setup - node@v4 with : node-version : '22' cache : 'npm' - run : npm ci - name : Run migrations run : npx prisma migrate deploy env : DATABASE_URL : postgresql : //ci_user : $ { { secrets.CI_DB_PASSWORD } } @localhost : 5432/testdb - name : Integration tests run : npm run test : integration env : DATABASE_URL : postgresql : //ci_user : $ { { secrets.CI_DB_PASSWORD } } @localhost : 5432/testdb Note: Even for CI-only test databases, use GitHub Secrets for credentials rather than hardcoding values. This builds good habits and prevents accidental reuse of test credentials in other contexts. E2E Tests e2e : runs-on : ubuntu - latest steps : - uses : actions/checkout@v4 - uses : actions/setup - node@v4 with : node-version : '22' cache : 'npm' - run : npm ci - name : Install Playwright run : npx playwright install - - with - deps chromium - name : Build run : npm run build - name : Run E2E tests run : npx playwright test - uses : actions/upload - artifact@v4 if : failure() with : name : playwright - report path : playwright - report/ Feeding CI Failures Back to Agents The power of CI with AI agents is the feedback loop. When CI fails: CI fails │ ▼ Copy the failure output │ ▼ Feed it to the agent: "The CI pipeline failed with this error: [paste specific error] Fix the issue and verify locally before pushing again." │ ▼ Agent fixes → pushes → CI runs again Key patterns: Lint failure → Agent runs npm run lint --fix and commits Type error → Agent reads the error location and fixes the type Test failure → Agent follows debugging-and-error-recovery skill Build error → Agent checks config and dependencies Deployment Strategies Preview Deployments Every PR gets a preview deployment for manual testing:

Deploy preview on PR (Vercel/Netlify/etc.)

deploy-preview : runs-on : ubuntu - latest if : github.event_name == 'pull_request' steps : - uses : actions/checkout@v4 - name : Deploy preview run : npx vercel - - token=$ { { secrets.VERCEL_TOKEN } } Feature Flags Feature flags decouple deployment from release. Deploy incomplete or risky features behind flags so you can: Ship code without enabling it. Merge to main early, enable when ready. Roll back without redeploying. Disable the flag instead of reverting code. Canary new features. Enable for 1% of users, then 10%, then 100%. Run A/B tests. Compare behavior with and without the feature. // Simple feature flag pattern if ( featureFlags . isEnabled ( 'new-checkout-flow' , { userId } ) ) { return renderNewCheckout ( ) ; } return renderLegacyCheckout ( ) ; Flag lifecycle: Create → Enable for testing → Canary → Full rollout → Remove the flag and dead code. Flags that live forever become technical debt — set a cleanup date when you create them. Staged Rollouts PR merged to main │ ▼ Staging deployment (auto) │ Manual verification ▼ Production deployment (manual trigger or auto after staging) │ ▼ Monitor for errors (15-minute window) │ ├── Errors detected → Rollback └── Clean → Done Rollback Plan Every deployment should be reversible:

Manual rollback workflow

name : Rollback on : workflow_dispatch : inputs : version : description : 'Version to rollback to' required : true jobs : rollback : runs-on : ubuntu - latest steps : - name : Rollback deployment run : |

Deploy the specified previous version

npx vercel rollback ${{ inputs.version }} Environment Management .env.example → Committed (template for developers) .env → NOT committed (local development) .env.test → Committed (test environment, no real secrets) CI secrets → Stored in GitHub Secrets / vault Production secrets → Stored in deployment platform / vault CI should never have production secrets. Use separate secrets for CI testing. Automation Beyond CI Dependabot / Renovate

.github/dependabot.yml

version : 2 updates : - package-ecosystem : npm directory : / schedule : interval : weekly open-pull-requests-limit : 5 Build Cop Role Designate someone responsible for keeping CI green. When the build breaks, the Build Cop's job is to fix or revert — not the person whose change caused the break. This prevents broken builds from accumulating while everyone assumes someone else will fix it. PR Checks Required reviews: At least 1 approval before merge Required status checks: CI must pass before merge Branch protection: No force-pushes to main Auto-merge: If all checks pass and approved, merge automatically CI Optimization When the pipeline exceeds 10 minutes, apply these strategies in order of impact: Slow CI pipeline? ├── Cache dependencies │ └── Use actions/cache or setup-node cache option for node_modules ├── Run jobs in parallel │ └── Split lint, typecheck, test, build into separate parallel jobs ├── Only run what changed │ └── Use path filters to skip unrelated jobs (e.g., skip e2e for docs-only PRs) ├── Use matrix builds │ └── Shard test suites across multiple runners ├── Optimize the test suite │ └── Remove slow tests from the critical path, run them on a schedule instead └── Use larger runners └── GitHub-hosted larger runners or self-hosted for CPU-heavy builds Example: caching and parallelism jobs : lint : runs-on : ubuntu - latest steps : - uses : actions/checkout@v4 - uses : actions/setup - node@v4 with : { node-version : '22' , cache : 'npm' } - run : npm ci - run : npm run lint typecheck : runs-on : ubuntu - latest steps : - uses : actions/checkout@v4 - uses : actions/setup - node@v4 with : { node-version : '22' , cache : 'npm' } - run : npm ci - run : npx tsc - - noEmit test : runs-on : ubuntu - latest steps : - uses : actions/checkout@v4 - uses : actions/setup - node@v4 with : { node-version : '22' , cache : 'npm' } - run : npm ci - run : npm test - - - - coverage Common Rationalizations Rationalization Reality "CI is too slow" Optimize the pipeline (see CI Optimization below), don't skip it. A 5-minute pipeline prevents hours of debugging. "This change is trivial, skip CI" Trivial changes break builds. CI is fast for trivial changes anyway. "The test is flaky, just re-run" Flaky tests mask real bugs and waste everyone's time. Fix the flakiness. "We'll add CI later" Projects without CI accumulate broken states. Set it up on day one. "Manual testing is enough" Manual testing doesn't scale and isn't repeatable. Automate what you can. Red Flags No CI pipeline in the project CI failures ignored or silenced Tests disabled in CI to make the pipeline pass Production deploys without staging verification No rollback mechanism Secrets stored in code or CI config files (not secrets manager) Long CI times with no optimization effort Verification After setting up or modifying CI: All quality gates are present (lint, types, tests, build, audit) Pipeline runs on every PR and push to main Failures block merge (branch protection configured) CI results feed back into the development loop Secrets are stored in the secrets manager, not in code Deployment has a rollback mechanism Pipeline runs in under 10 minutes for the test suite