# AGENTS.md — core-api

**Tag:** core-composition

**Composition-only package** that aggregates feature tRPC routers into a single root `appRouter`. It does not define procedures; instead, it imports them from feature packages.

## Responsibilities

- **Compose tRPC appRouter** — merges feature routers into `t.router({ ... })`
- **Type export** — exports `AppRouter` type for frontend type safety
- **No procedure definitions** — all routers owned by their respective features (`@repo/auth`, `@repo/blog`, etc.)
- **No business logic** — purely structural assembly

## Allowed imports

- **`@repo/<feature>/api`** subpath exports only (to get tRPC routers)
  - e.g., `import { authRouter } from "@repo/auth/api"`
  - e.g., `import { blogRouter } from "@repo/blog/api"`
  - e.g., `import { navigationRouter } from "@repo/navigation/api"`
- `@repo/core-shared/trpc/init` — for `t.router()` builder

## Must NOT import

- Any feature's root package or other subpaths (e.g., NOT `@repo/blog/di`, NOT `@repo/blog/entities`)
- Any app package
- `@repo/core-cms`, `@repo/core-trpc`, `@repo/core-ui`

## Public exports

From `package.json`:
- `.` — `appRouter` and `AppRouter` type

Example usage:
```typescript
import { appRouter, type AppRouter } from "@repo/core-api";
```

## Test conventions

- No unit tests (composition layer)
- Verify at app boot: `pnpm dev --filter @repo/web-next` succeeds and tRPC client fetches data
- Run router health check: `pnpm typecheck` confirms `AppRouter` type is valid

## Structure

```
src/
  root.ts                    # t.router({ ... }) aggregating all feature routers
  index.ts                   # re-exports appRouter + type
```