Plans execute autonomously. Checkpoints formalize the interaction points where human verification or decisions are needed. **Core principle:** Claude automates everything with CLI/API. Checkpoints are for verification and decisions, not manual work. **Golden rules:** 1. **If Claude can run it, Claude runs it** - Never ask user to execute CLI commands, start servers, or run builds 2. **Claude sets up the verification environment** - Start dev servers, seed databases, configure env vars 3. **User only does what requires human judgment** - Visual checks, UX evaluation, "does this feel right?" 4. **Secrets come from user, automation comes from Claude** - Ask for API keys, then Claude uses them via CLI ## checkpoint:human-verify (Most Common - 90%) **When:** Claude completed automated work, human confirms it works correctly. **Use for:** - Visual UI checks (layout, styling, responsiveness) - Interactive flows (click through wizard, test user flows) - Functional verification (feature works as expected) - Audio/video playback quality - Animation smoothness - Accessibility testing **Structure:** ```xml [What Claude automated and deployed/built] [Exact steps to test - URLs, commands, expected behavior] [How to continue - "approved", "yes", or describe issues] ``` **Key elements:** - ``: What Claude automated (deployed, built, configured) - ``: Exact steps to confirm it works (numbered, specific) - ``: Clear indication of how to continue **Example: Vercel Deployment** ```xml Deploy to Vercel .vercel/, vercel.json Run `vercel --yes` to create project and deploy. Capture deployment URL from output. vercel ls shows deployment, curl {url} returns 200 App deployed, URL captured Deployed to Vercel at https://myapp-abc123.vercel.app Visit https://myapp-abc123.vercel.app and confirm: - Homepage loads without errors - Login form is visible - No console errors in browser DevTools Type "approved" to continue, or describe issues to fix ``` **Example: UI Component** ```xml Build responsive dashboard layout src/components/Dashboard.tsx, src/app/dashboard/page.tsx Create dashboard with sidebar, header, and content area. Use Tailwind responsive classes for mobile. npm run build succeeds, no TypeScript errors Dashboard component builds without errors Start dev server for verification Run `npm run dev` in background, wait for "ready" message, capture port curl http://localhost:3000 returns 200 Dev server running at http://localhost:3000 Responsive dashboard layout - dev server running at http://localhost:3000 Visit http://localhost:3000/dashboard and verify: 1. Desktop (>1024px): Sidebar left, content right, header top 2. Tablet (768px): Sidebar collapses to hamburger menu 3. Mobile (375px): Single column layout, bottom nav appears 4. No layout shift or horizontal scroll at any size Type "approved" or describe layout issues ``` **Key pattern:** Claude starts the dev server BEFORE the checkpoint. User only needs to visit the URL. **Example: Xcode Build** ```xml Build macOS app with Xcode App.xcodeproj, Sources/ Run `xcodebuild -project App.xcodeproj -scheme App build`. Check for compilation errors in output. Build output contains "BUILD SUCCEEDED", no errors App builds successfully Built macOS app at DerivedData/Build/Products/Debug/App.app Open App.app and test: - App launches without crashes - Menu bar icon appears - Preferences window opens correctly - No visual glitches or layout issues Type "approved" or describe issues ``` ## checkpoint:decision (9%) **When:** Human must make choice that affects implementation direction. **Use for:** - Technology selection (which auth provider, which database) - Architecture decisions (monorepo vs separate repos) - Design choices (color scheme, layout approach) - Feature prioritization (which variant to build) - Data model decisions (schema structure) **Structure:** ```xml [What's being decided] [Why this decision matters] [Option name] [Benefits] [Tradeoffs] [Option name] [Benefits] [Tradeoffs] [How to indicate choice] ``` **Key elements:** - ``: What's being decided - ``: Why this matters - ``: Each option with balanced pros/cons (not prescriptive) - ``: How to indicate choice **Example: Auth Provider Selection** ```xml Select authentication provider Need user authentication for the app. Three solid options with different tradeoffs. Supabase Auth Built-in with Supabase DB we're using, generous free tier, row-level security integration Less customizable UI, tied to Supabase ecosystem Clerk Beautiful pre-built UI, best developer experience, excellent docs Paid after 10k MAU, vendor lock-in NextAuth.js Free, self-hosted, maximum control, widely adopted More setup work, you manage security updates, UI is DIY Select: supabase, clerk, or nextauth ``` **Example: Database Selection** ```xml Select database for user data App needs persistent storage for users, sessions, and user-generated content. Expected scale: 10k users, 1M records first year. Supabase (Postgres) Full SQL, generous free tier, built-in auth, real-time subscriptions Vendor lock-in for real-time features, less flexible than raw Postgres PlanetScale (MySQL) Serverless scaling, branching workflow, excellent DX MySQL not Postgres, no foreign keys in free tier Convex Real-time by default, TypeScript-native, automatic caching Newer platform, different mental model, less SQL flexibility Select: supabase, planetscale, or convex ``` ## checkpoint:human-action (1% - Rare) **When:** Action has NO CLI/API and requires human-only interaction, OR Claude hit an authentication gate during automation. **Use ONLY for:** - **Authentication gates** - Claude tried to use CLI/API but needs credentials to continue (this is NOT a failure) - Email verification links (account creation requires clicking email) - SMS 2FA codes (phone verification) - Manual account approvals (platform requires human review before API access) - Credit card 3D Secure flows (web-based payment authorization) - OAuth app approvals (some platforms require web-based approval) **Do NOT use for pre-planned manual work:** - Manually deploying to Vercel (use `vercel` CLI - auth gate if needed) - Manually creating Stripe webhooks (use Stripe API - auth gate if needed) - Manually creating databases (use provider CLI - auth gate if needed) - Running builds/tests manually (use Bash tool) - Creating files manually (use Write tool) **Structure:** ```xml [What human must do - Claude already did everything automatable] [What Claude already automated] [The ONE thing requiring human action] [What Claude can check afterward] [How to continue] ``` **Key principle:** Claude automates EVERYTHING possible first, only asks human for the truly unavoidable manual step. **Example: Email Verification** ```xml Create SendGrid account via API Use SendGrid API to create subuser account with provided email. Request verification email. API returns 201, account created Account created, verification email sent Complete email verification for SendGrid account I created the account and requested verification email. Check your inbox for SendGrid verification link and click it. SendGrid API key works: curl test succeeds Type "done" when email verified ``` **Example: Credit Card 3D Secure** ```xml Create Stripe payment intent Use Stripe API to create payment intent for $99. Generate checkout URL. Stripe API returns payment intent ID and URL Payment intent created Complete 3D Secure authentication I created the payment intent: https://checkout.stripe.com/pay/cs_test_abc123 Visit that URL and complete the 3D Secure verification flow with your test card. Stripe webhook receives payment_intent.succeeded event Type "done" when payment completes ``` **Example: Authentication Gate (Dynamic Checkpoint)** ```xml Deploy to Vercel .vercel/, vercel.json Run `vercel --yes` to deploy vercel ls shows deployment, curl returns 200 Authenticate Vercel CLI so I can continue deployment I tried to deploy but got authentication error. Run: vercel login This will open your browser - complete the authentication flow. vercel whoami returns your account email Type "done" when authenticated Retry Vercel deployment Run `vercel --yes` (now authenticated) vercel ls shows deployment, curl returns 200 ``` **Key distinction:** Authentication gates are created dynamically when Claude encounters auth errors during automation. They're NOT pre-planned - Claude tries to automate first, only asks for credentials when blocked. When Claude encounters `type="checkpoint:*"`: 1. **Stop immediately** - do not proceed to next task 2. **Display checkpoint clearly** using the format below 3. **Wait for user response** - do not hallucinate completion 4. **Verify if possible** - check files, run tests, whatever is specified 5. **Resume execution** - continue to next task only after confirmation **For checkpoint:human-verify:** ``` ╔═══════════════════════════════════════════════════════╗ ║ CHECKPOINT: Verification Required ║ ╚═══════════════════════════════════════════════════════╝ Progress: 5/8 tasks complete Task: Responsive dashboard layout Built: Responsive dashboard at /dashboard How to verify: 1. Run: npm run dev 2. Visit: http://localhost:3000/dashboard 3. Desktop (>1024px): Sidebar visible, content fills remaining space 4. Tablet (768px): Sidebar collapses to icons 5. Mobile (375px): Sidebar hidden, hamburger menu appears ──────────────────────────────────────────────────────── → YOUR ACTION: Type "approved" or describe issues ──────────────────────────────────────────────────────── ``` **For checkpoint:decision:** ``` ╔═══════════════════════════════════════════════════════╗ ║ CHECKPOINT: Decision Required ║ ╚═══════════════════════════════════════════════════════╝ Progress: 2/6 tasks complete Task: Select authentication provider Decision: Which auth provider should we use? Context: Need user authentication. Three options with different tradeoffs. Options: 1. supabase - Built-in with our DB, free tier Pros: Row-level security integration, generous free tier Cons: Less customizable UI, ecosystem lock-in 2. clerk - Best DX, paid after 10k users Pros: Beautiful pre-built UI, excellent documentation Cons: Vendor lock-in, pricing at scale 3. nextauth - Self-hosted, maximum control Pros: Free, no vendor lock-in, widely adopted Cons: More setup work, DIY security updates ──────────────────────────────────────────────────────── → YOUR ACTION: Select supabase, clerk, or nextauth ──────────────────────────────────────────────────────── ``` **For checkpoint:human-action:** ``` ╔═══════════════════════════════════════════════════════╗ ║ CHECKPOINT: Action Required ║ ╚═══════════════════════════════════════════════════════╝ Progress: 3/8 tasks complete Task: Deploy to Vercel Attempted: vercel --yes Error: Not authenticated. Please run 'vercel login' What you need to do: 1. Run: vercel login 2. Complete browser authentication when it opens 3. Return here when done I'll verify: vercel whoami returns your account ──────────────────────────────────────────────────────── → YOUR ACTION: Type "done" when authenticated ──────────────────────────────────────────────────────── ``` **Critical:** When Claude tries CLI/API and gets auth error, this is NOT a failure - it's a gate requiring human input to unblock automation. **Pattern:** Claude tries automation → auth error → creates checkpoint → you authenticate → Claude retries → continues **Gate protocol:** 1. Recognize it's not a failure - missing auth is expected 2. Stop current task - don't retry repeatedly 3. Create checkpoint:human-action dynamically 4. Provide exact authentication steps 5. Verify authentication works 6. Retry the original task 7. Continue normally **Example execution flow (Vercel auth gate):** ``` Claude: Running `vercel --yes` to deploy... Error: Not authenticated. Please run 'vercel login' ╔═══════════════════════════════════════════════════════╗ ║ CHECKPOINT: Action Required ║ ╚═══════════════════════════════════════════════════════╝ Progress: 2/8 tasks complete Task: Deploy to Vercel Attempted: vercel --yes Error: Not authenticated What you need to do: 1. Run: vercel login 2. Complete browser authentication I'll verify: vercel whoami returns your account ──────────────────────────────────────────────────────── → YOUR ACTION: Type "done" when authenticated ──────────────────────────────────────────────────────── User: done Claude: Verifying authentication... Running: vercel whoami ✓ Authenticated as: user@example.com Retrying deployment... Running: vercel --yes ✓ Deployed to: https://myapp-abc123.vercel.app Task 3 complete. Continuing to task 4... ``` **Key distinction:** - Pre-planned checkpoint: "I need you to do X" (wrong - Claude should automate) - Auth gate: "I tried to automate X but need credentials" (correct - unblocks automation) **The rule:** If it has CLI/API, Claude does it. Never ask human to perform automatable work. ## Service CLI Reference | Service | CLI/API | Key Commands | Auth Gate | |---------|---------|--------------|-----------| | Vercel | `vercel` | `--yes`, `env add`, `--prod`, `ls` | `vercel login` | | Railway | `railway` | `init`, `up`, `variables set` | `railway login` | | Fly | `fly` | `launch`, `deploy`, `secrets set` | `fly auth login` | | Stripe | `stripe` + API | `listen`, `trigger`, API calls | API key in .env | | Supabase | `supabase` | `init`, `link`, `db push`, `gen types` | `supabase login` | | Upstash | `upstash` | `redis create`, `redis get` | `upstash auth login` | | PlanetScale | `pscale` | `database create`, `branch create` | `pscale auth login` | | GitHub | `gh` | `repo create`, `pr create`, `secret set` | `gh auth login` | | Node | `npm`/`pnpm` | `install`, `run build`, `test`, `run dev` | N/A | | Xcode | `xcodebuild` | `-project`, `-scheme`, `build`, `test` | N/A | | Convex | `npx convex` | `dev`, `deploy`, `env set`, `env get` | `npx convex login` | ## Environment Variable Automation **Env files:** Use Write/Edit tools. Never ask human to create .env manually. **Dashboard env vars via CLI:** | Platform | CLI Command | Example | |----------|-------------|---------| | Convex | `npx convex env set` | `npx convex env set OPENAI_API_KEY sk-...` | | Vercel | `vercel env add` | `vercel env add STRIPE_KEY production` | | Railway | `railway variables set` | `railway variables set API_KEY=value` | | Fly | `fly secrets set` | `fly secrets set DATABASE_URL=...` | | Supabase | `supabase secrets set` | `supabase secrets set MY_SECRET=value` | **Pattern for secret collection:** ```xml Add OPENAI_API_KEY to Convex dashboard Go to dashboard.convex.dev → Settings → Environment Variables → Add Provide your OpenAI API key I need your OpenAI API key to configure the Convex backend. Get it from: https://platform.openai.com/api-keys Paste the key (starts with sk-) I'll add it via `npx convex env set` and verify it's configured Paste your API key Configure OpenAI key in Convex Run `npx convex env set OPENAI_API_KEY {user-provided-key}` `npx convex env get OPENAI_API_KEY` returns the key (masked) ``` ## Dev Server Automation **Claude starts servers, user visits URLs:** | Framework | Start Command | Ready Signal | Default URL | |-----------|---------------|--------------|-------------| | Next.js | `npm run dev` | "Ready in" or "started server" | http://localhost:3000 | | Vite | `npm run dev` | "ready in" | http://localhost:5173 | | Convex | `npx convex dev` | "Convex functions ready" | N/A (backend only) | | Express | `npm start` | "listening on port" | http://localhost:3000 | | Django | `python manage.py runserver` | "Starting development server" | http://localhost:8000 | ### Server Lifecycle Protocol **Starting servers:** ```bash # Run in background, capture PID for cleanup npm run dev & DEV_SERVER_PID=$! # Wait for ready signal (max 30s) timeout 30 bash -c 'until curl -s localhost:3000 > /dev/null 2>&1; do sleep 1; done' ``` **Port conflicts:** If default port is in use, check what's running and either: 1. Kill the existing process if it's stale: `lsof -ti:3000 | xargs kill` 2. Use alternate port: `npm run dev -- --port 3001` **Server stays running** for the duration of the checkpoint. After user approves, server continues running for subsequent tasks. Only kill explicitly if: - Plan is complete and no more verification needed - Switching to production deployment - Port needed for different service **Pattern:** ```xml Start dev server Run `npm run dev` in background, wait for ready signal curl http://localhost:3000 returns 200 Dev server running Feature X - dev server running at http://localhost:3000 Visit http://localhost:3000/feature and verify: 1. [Visual check 1] 2. [Visual check 2] ``` ## CLI Installation Handling **When a required CLI is not installed:** | CLI | Auto-install? | Command | |-----|---------------|---------| | npm/pnpm/yarn | No - ask user | User chooses package manager | | vercel | Yes | `npm i -g vercel` | | gh (GitHub) | Yes | `brew install gh` (macOS) or `apt install gh` (Linux) | | stripe | Yes | `npm i -g stripe` | | supabase | Yes | `npm i -g supabase` | | convex | No - use npx | `npx convex` (no install needed) | | fly | Yes | `brew install flyctl` or curl installer | | railway | Yes | `npm i -g @railway/cli` | **Protocol:** 1. Try the command 2. If "command not found", check if auto-installable 3. If yes: install silently, retry command 4. If no: create checkpoint asking user to install ```xml Install Vercel CLI Run `npm i -g vercel` `vercel --version` succeeds Vercel CLI installed ``` ## Pre-Checkpoint Automation Failures **When setup fails before checkpoint:** | Failure | Response | |---------|----------| | Server won't start | Check error output, fix issue, retry (don't proceed to checkpoint) | | Port in use | Kill stale process or use alternate port | | Missing dependency | Run `npm install`, retry | | Build error | Fix the error first (this is a bug, not a checkpoint issue) | | Auth error | Create auth gate checkpoint | | Network timeout | Retry with backoff, then checkpoint if persistent | **Key principle:** Never present a checkpoint with broken verification environment. If `curl localhost:3000` fails, don't ask user to "visit localhost:3000". ```xml Dashboard (server failed to start) Visit http://localhost:3000... Fix server startup issue Investigate error, fix root cause, restart server curl http://localhost:3000 returns 200 Server running correctly Dashboard - server running at http://localhost:3000 Visit http://localhost:3000/dashboard... ``` ## Quick Reference | Action | Automatable? | Claude does it? | |--------|--------------|-----------------| | Deploy to Vercel | Yes (`vercel`) | YES | | Create Stripe webhook | Yes (API) | YES | | Write .env file | Yes (Write tool) | YES | | Create Upstash DB | Yes (`upstash`) | YES | | Run tests | Yes (`npm test`) | YES | | Start dev server | Yes (`npm run dev`) | YES | | Add env vars to Convex | Yes (`npx convex env set`) | YES | | Add env vars to Vercel | Yes (`vercel env add`) | YES | | Seed database | Yes (CLI/API) | YES | | Click email verification link | No | NO | | Enter credit card with 3DS | No | NO | | Complete OAuth in browser | No | NO | | Visually verify UI looks correct | No | NO | | Test interactive user flows | No | NO | **DO:** - Automate everything with CLI/API before checkpoint - Be specific: "Visit https://myapp.vercel.app" not "check deployment" - Number verification steps: easier to follow - State expected outcomes: "You should see X" - Provide context: why this checkpoint exists - Make verification executable: clear, testable steps **DON'T:** - Ask human to do work Claude can automate (deploy, create resources, run builds) - Assume knowledge: "Configure the usual settings" ❌ - Skip steps: "Set up database" ❌ (too vague) - Mix multiple verifications in one checkpoint (split them) - Make verification impossible (Claude can't check visual appearance without user confirmation) **Placement:** - **After automation completes** - not before Claude does the work - **After UI buildout** - before declaring phase complete - **Before dependent work** - decisions before implementation - **At integration points** - after configuring external services **Bad placement:** - Before Claude automates (asking human to do automatable work) ❌ - Too frequent (every other task is a checkpoint) ❌ - Too late (checkpoint is last task, but earlier tasks needed its result) ❌ ### Example 1: Deployment Flow (Correct) ```xml Deploy to Vercel .vercel/, vercel.json, package.json 1. Run `vercel --yes` to create project and deploy 2. Capture deployment URL from output 3. Set environment variables with `vercel env add` 4. Trigger production deployment with `vercel --prod` - vercel ls shows deployment - curl {url} returns 200 - Environment variables set correctly App deployed to production, URL captured Deployed to https://myapp.vercel.app Visit https://myapp.vercel.app and confirm: - Homepage loads correctly - All images/assets load - Navigation works - No console errors Type "approved" or describe issues ``` ### Example 2: Database Setup (No Checkpoint Needed) ```xml Create Upstash Redis database .env 1. Run `upstash redis create myapp-cache --region us-east-1` 2. Capture connection URL from output 3. Write to .env: UPSTASH_REDIS_URL={url} 4. Verify connection with test command - upstash redis list shows database - .env contains UPSTASH_REDIS_URL - Test connection succeeds Redis database created and configured ``` ### Example 3: Stripe Webhooks (Correct) ```xml Configure Stripe webhooks .env, src/app/api/webhooks/route.ts 1. Use Stripe API to create webhook endpoint pointing to /api/webhooks 2. Subscribe to events: payment_intent.succeeded, customer.subscription.updated 3. Save webhook signing secret to .env 4. Implement webhook handler in route.ts - Stripe API returns webhook endpoint ID - .env contains STRIPE_WEBHOOK_SECRET - curl webhook endpoint returns 200 Stripe webhooks configured and handler implemented Stripe webhook configured via API Visit Stripe Dashboard > Developers > Webhooks Confirm: Endpoint shows https://myapp.com/api/webhooks with correct events Type "yes" if correct ``` ### Example 4: Full Auth Flow Verification (Correct) ```xml Create user schema src/db/schema.ts Define User, Session, Account tables with Drizzle ORM npm run db:generate succeeds Create auth API routes src/app/api/auth/[...nextauth]/route.ts Set up NextAuth with GitHub provider, JWT strategy TypeScript compiles, no errors Create login UI src/app/login/page.tsx, src/components/LoginButton.tsx Create login page with GitHub OAuth button npm run build succeeds Start dev server for auth testing Run `npm run dev` in background, wait for ready signal curl http://localhost:3000 returns 200 Dev server running at http://localhost:3000 Complete authentication flow - dev server running at http://localhost:3000 1. Visit: http://localhost:3000/login 2. Click "Sign in with GitHub" 3. Complete GitHub OAuth flow 4. Verify: Redirected to /dashboard, user name displayed 5. Refresh page: Session persists 6. Click logout: Session cleared Type "approved" or describe issues ``` ### ❌ BAD: Asking user to start dev server ```xml Dashboard component 1. Run: npm run dev 2. Visit: http://localhost:3000/dashboard 3. Check layout is correct ``` **Why bad:** Claude can run `npm run dev`. User should only visit URLs, not execute commands. ### ✅ GOOD: Claude starts server, user visits ```xml Start dev server Run `npm run dev` in background curl localhost:3000 returns 200 Dashboard at http://localhost:3000/dashboard (server running) Visit http://localhost:3000/dashboard and verify: 1. Layout matches design 2. No console errors ``` ### ❌ BAD: Asking user to add env vars in dashboard ```xml Add environment variables to Convex 1. Go to dashboard.convex.dev 2. Select your project 3. Navigate to Settings → Environment Variables 4. Add OPENAI_API_KEY with your key ``` **Why bad:** Convex has `npx convex env set`. Claude should ask for the key value, then run the CLI command. ### ✅ GOOD: Claude collects secret, adds via CLI ```xml Provide your OpenAI API key I need your OpenAI API key. Get it from: https://platform.openai.com/api-keys Paste the key below (starts with sk-) I'll configure it via CLI Paste your key Add OpenAI key to Convex Run `npx convex env set OPENAI_API_KEY {key}` `npx convex env get` shows OPENAI_API_KEY configured ``` ### ❌ BAD: Asking human to deploy ```xml Deploy to Vercel 1. Visit vercel.com/new 2. Import Git repository 3. Click Deploy 4. Copy deployment URL Deployment exists Paste URL ``` **Why bad:** Vercel has a CLI. Claude should run `vercel --yes`. ### ✅ GOOD: Claude automates, human verifies ```xml Deploy to Vercel Run `vercel --yes`. Capture URL. vercel ls shows deployment, curl returns 200 Deployed to {url} Visit {url}, check homepage loads Type "approved" ``` ### ❌ BAD: Too many checkpoints ```xml Create schema Check schema Create API route Check API Create UI form Check form ``` **Why bad:** Verification fatigue. Combine into one checkpoint at end. ### ✅ GOOD: Single verification checkpoint ```xml Create schema Create API route Create UI form Complete auth flow (schema + API + UI) Test full flow: register, login, access protected page Type "approved" ``` ### ❌ BAD: Asking for automatable file operations ```xml Create .env file 1. Create .env in project root 2. Add: DATABASE_URL=... 3. Add: STRIPE_KEY=... ``` **Why bad:** Claude has Write tool. This should be `type="auto"`. ### ❌ BAD: Vague verification steps ```xml Dashboard Check it works Continue ``` **Why bad:** No specifics. User doesn't know what to test or what "works" means. ### ✅ GOOD: Specific verification steps (server already running) ```xml Responsive dashboard - server running at http://localhost:3000 Visit http://localhost:3000/dashboard and verify: 1. Desktop (>1024px): Sidebar visible, content area fills remaining space 2. Tablet (768px): Sidebar collapses to icons 3. Mobile (375px): Sidebar hidden, hamburger menu in header 4. No horizontal scroll at any size Type "approved" or describe layout issues ``` ### ❌ BAD: Asking user to run any CLI command ```xml Run database migrations 1. Run: npx prisma migrate deploy 2. Run: npx prisma db seed 3. Verify tables exist ``` **Why bad:** Claude can run these commands. User should never execute CLI commands. ### ❌ BAD: Asking user to copy values between services ```xml Configure webhook URL in Stripe 1. Copy the deployment URL from terminal 2. Go to Stripe Dashboard → Webhooks 3. Add endpoint with URL + /api/webhooks 4. Copy webhook signing secret 5. Add to .env file ``` **Why bad:** Stripe has an API. Claude should create the webhook via API and write to .env directly.

Checkpoints formalize human-in-the-loop points. Use them when Claude cannot complete a task autonomously OR when human verification is required for correctness. **The golden rule:** If Claude CAN automate it, Claude MUST automate it. **Checkpoint priority:** 1. **checkpoint:human-verify** (90% of checkpoints) - Claude automated everything, human confirms visual/functional correctness 2. **checkpoint:decision** (9% of checkpoints) - Human makes architectural/technology choices 3. **checkpoint:human-action** (1% of checkpoints) - Truly unavoidable manual steps with no API/CLI **When NOT to use checkpoints:** - Things Claude can verify programmatically (tests pass, build succeeds) - File operations (Claude can read files to verify) - Code correctness (use tests and static analysis) - Anything automatable via CLI/API