Generate Infra

SST v3 Infrastructure Stack

Wire up a Bun monorepo prototype for AWS deployment using SST v3 (Ion). Lambda functions run nodejs22.x (not Bun — Bun is the local dev/build runtime only). Hono apps bridge to Lambda via hono/aws-lambda. Infrastructure modules live in infra/ and are imported by sst.config.ts at the repo root.

Defaults and Deviations

These are team defaults. In execution mode, follow them unless the project CLAUDE.md explicitly overrides them.

In Plan mode, apply the deviation protocol from prototyping-skills:team-conventions: state the default, name the alternative, explain the trade-off, flag the blast radius, let the human decide.

Key defaults:

• SST version: v3 (Ion) — not SST v2
• Lambda runtime: nodejs22.x — never bun or nodejs18.x
• Secrets: sst.Secret for all sensitive vars — never plaintext in infra files
• Removal policy: retain for production, remove for all other stages
• Env bridging: Bridge Resource.<X>.value to process.env.X at handler top — app packages read process.env or Bun.env, not SST at runtime

Pre-flight Checklist

Run ALL of these checks before generating any file:

1. Detect packages: ls packages/ — record which of api, ui, core, mcp exist
2. Detect UI framework: grep '"next"' packages/ui/package.json 2>/dev/null — only generate infra/frontend.ts if Next.js is confirmed
3. Detect env vars: cat .env.example 2>/dev/null then grep for Bun.env. and process.env. across all packages — build the full list of secrets to declare
4. Detect native modules: grep -r '@libsql/client\|better-sqlite3' packages/*/package.json 2>/dev/null — add nodejs.install if found
5. Pipeline gate — use AskUserQuestion: "Does this project have a background processing pipeline? (queue-based jobs, scheduled Lambda functions, cron workers)"
6. App name gate — use AskUserQuestion: "What is the SST app name? (kebab-case, e.g. 'my-prototype') This becomes the CloudFormation stack prefix."

App Export Split (Critical)

Every project built with init-prototype has packages/api/src/index.ts exporting: export default { port, fetch: app.fetch }. Lambda cannot use this — it needs a Hono app exported from a separate module. Detect before generating infra:

grep -l "export default.*fetch" packages/api/src/index.ts

If found:

1. Create packages/api/src/app.ts — move the Hono app construction and all route mounts here, add export default app
2. Update packages/api/src/index.ts — import app from ./app.js (.js required for ESM), keep only the Bun server entry (Bun.serve({ port, fetch: app.fetch }))

See references/sst-patterns.md → App Export Split for full file templates.

Step-by-Step Execution

Execute all steps in order. Skip steps whose conditions aren't met (e.g. skip Step 7 if no Next.js).

Step 1 — Root package.json scripts

Add "sst": "^3.0.0" to root package.json devDependencies. Add scripts:

"sst:dev": "sst dev",
"sst:deploy": "sst deploy",
"sst:remove": "sst remove"

Step 2 — infra/secrets.ts

Convert all detected env vars to sst.Secret() declarations. Conversion rule: SNAKE_CASE → PascalCase per segment (OPENAI_API_KEY → OpenaiApiKey). Add all to the allSecrets array and export it. Exclusions: NEXT_PUBLIC_*, PORT, NODE_ENV.

See Secret Name Conversion Table below and references/sst-patterns.md → infra/secrets.ts.

Step 3 — sst.config.ts

Always generate. Import only the infra modules that were actually generated. Set removal: input?.stage === "production" ? "retain" : "remove". Use the app name provided by the user in Step 0.

See references/sst-patterns.md → sst.config.ts.

Step 4 — App export split

Run the detection from App Export Split above. Create app.ts and fix index.ts if needed. This must be done before generating infra handler files.

Step 5 — infra/api.ts (if packages/api exists)

Generate sst.aws.Function("Api", ...) with runtime nodejs22.x, timeout 30 seconds, memory 512 MB, link: allSecrets, url: true. Add nodejs.install for native deps if detected in pre-flight. Export apiUrl.

See references/sst-patterns.md → infra/api.ts.

Step 6 — infra/functions/api.ts (if packages/api exists)

Generate the Lambda handler: import handle from hono/aws-lambda and the Hono app from ../../packages/api/src/app.js (.js extension required for ESM). Bridge all detected secrets to process.env using ??=. Export handler.

See references/sst-patterns.md → infra/functions/api.ts.

Step 7 — infra/frontend.ts (if Next.js confirmed)

Generate sst.aws.Nextjs("Frontend", { path: "packages/ui", environment: {...} }). NEXT_PUBLIC_API_URL gets apiUrl (stack output — not a secret). Auth vars (NEXTAUTH_SECRET, NEXTAUTH_URL, GOOGLE_CLIENT_ID, GOOGLE_CLIENT_SECRET) get .value from their secrets. Export frontendUrl.

See references/sst-patterns.md → infra/frontend.ts.

Step 8 — infra/pipeline.ts (only if user confirmed pipeline)

Ask a follow-up with AskUserQuestion: "What triggers the pipeline — a queue (SQS), a schedule (cron), or both?" Then generate the appropriate pattern.

See references/sst-patterns.md → infra/pipeline.ts.

Step 9 — infra/tsconfig.json

Always generate. Extends ../tsconfig.json, includes ["**/*.ts", "../sst.config.ts"].

Step 10 — infra/CLAUDE.md

Always generate. Document secret-bridging convention, bundling rules, stage behavior, how to add new Lambdas, and SST commands.

See references/sst-patterns.md → infra/CLAUDE.md for exact content.

Secret Name Conversion Table

Rule: split on _, capitalize first letter of each word, join. GOOGLE_CX → GoogleCx.

Anti-Patterns

• Never hardcode secrets in infra files — always use sst.Secret
• Never use Bun.env in Lambda handlers — use process.env (bridged via ??=)
• Never bundle native modules (@libsql/client, better-sqlite3) with esbuild — use nodejs.install
• Never use sst.aws.Function for Next.js — use sst.aws.Nextjs
• Never omit the removal policy — always set removal in sst.config.ts
• Never import from application packages without .js extension in Lambda handlers — ESM requires explicit extensions

Verification Checklist

After generating all files, run the TypeScript check:

bunx tsc --noEmit -p infra/tsconfig.json

Fix any type errors before proceeding. Then create this task:

TaskCreate({
  subject: "Verify SST infrastructure before first deploy",
  description: "1. Set all secrets: npx sst secret set <Name> <value> — see infra/secrets.ts for full list\n2. bun run sst:dev — confirm API URL is printed\n3. curl <API_URL>/health — confirm 200 response\n4. If frontend: confirm CloudFront URL loads\n5. bun run sst:remove to tear down dev stack when done"
})