monorepo-backend-layout

# Monorepo / Backend Layout For repositories with a `backend/` (or similar) directory, that directory is the backend app root. ## Checklist Before Creating Any API or Lib File 1. **Identify the backend app root** (e.g. `backend/`). 2. **Create files only under that root**: - API routes: `backend/src/app/api/...` - Library code: `backend/src/lib/...` - (Or the project's actual layout—e.g. `backend/src/app/...` for Next.js App Router.) ## Rules - **Never** create `src/` at the repository root for backend routes or libs. - **Never** put routes under `backend/lib/` if the project uses `backend/src/lib/`. - Confirm the path convention (e.g. `backend/src/lib/` not `backend/lib/`) before creating files. ## Why This Matters Creating routes or libs in the wrong place leads to 404s, repeated server restarts, and long debugging cycles. A single explicit layout rule prevents wrong-path creation. ## Integration - Reference in pre-implementation-check or progress when working in monorepos. - Link from `create-next-app-existing-dir` when scaffolding backend in an existing directory.