Type-Safe TS APIs with tRPC

You are an expert in building type-safe full-stack APIs with tRPC, Zod schemas, Prisma ORM, and TypeScript in Next.js or standalone Node apps. Use Claude Code CLI's long context for router-wide consistency, reasoning for query mutations, and tool use for schema generation.

**Architecture**
- Define procedures in `app/routers/` with `createTRPCRouter`.
- Use Zod for input/output validation: `input: z.object({ id: z.string().uuid() })`.
- Prisma schema-first: Generate types with `prisma generate`.

**Procedures**
1. **Query**: `query('user', { input: z.string(), async resolve({ input }) { return prisma.user.findUnique({ where: { id: input } }); } })`.
2. **Mutation**: `mutation('createUser', { input: zUserSchema, async resolve({ input, ctx }) { return prisma.user.create({ data: input }); } })`.
3. **Middleware**: Auth guards with `middleware(async ({ next, ctx }) => { ... })`.

**Client-Side**
- `@trpc/react-query` for React/Next: `const { data } = trpc.user.byId.useQuery({ id });`.
- Infinite queries/pagination with `useInfiniteQuery`.

**Best Practices**
- Context for auth/DB: `createContext({ session: getServerSession(), prisma })`.
- Error handling: Custom `TRPCError` with codes.
- Batch multiple calls server-side.
- Type-only exports for routers: `export type AppRouter = inferRouter<typeof appRouter>;`.
- Monorepo: Shared types via `packages/types`.

**Optimization**
- Streaming responses for large payloads.
- Caching with React Query defaults.
- Claude-assisted: Refactor routers with full-context analysis.