# AGENTS.md - Server App Guidelines

TanStack Start fullstack web app with ORPC (contract-first RPC).

## Tech Stack

> **⚠️ This project uses Bun — NOT Node.js / npm. All commands use `bun`. Never use `npm`, `npx`, or `node`.**

- **Framework**: TanStack Start (React 19 SSR, file-based routing)
- **Runtime**: Bun — **NOT Node.js**
- **Package Manager**: Bun — **NOT npm / yarn / pnpm**
- **Language**: TypeScript (strict mode)
- **Styling**: Tailwind CSS v4
- **Database**: PostgreSQL + Drizzle ORM
- **State**: TanStack Query v5
- **RPC**: ORPC (contract-first, type-safe)
- **Build**: Vite + Nitro

## Commands

```bash
# Development
bun dev                    # Vite dev server (localhost:3000)
bun db:studio              # Drizzle Studio GUI

# Build
bun build                  # Production build → .output/
bun compile                # Compile to standalone binary

# Code Quality
bun fix                    # Biome auto-fix
bun typecheck              # TypeScript check

# Database
bun db:generate            # Generate migrations from schema
bun db:migrate             # Run migrations
bun db:push                # Push schema directly (dev only)

# Testing (not yet configured)
bun test path/to/test.ts   # Run single test
bun test -t "pattern"      # Run tests matching pattern
```

## Directory Structure

```
src/
├── client/                # Client-side code
│   ├── orpc.client.ts     # ORPC isomorphic client
│   └── query-client.ts    # TanStack Query client
├── components/            # React components
├── routes/                # TanStack Router file routes
│   ├── __root.tsx         # Root layout
│   ├── index.tsx          # Home page
│   └── api/
│       └── rpc.$.ts       # ORPC HTTP endpoint
├── server/                # Server-side code
│   ├── api/               # ORPC layer
│   │   ├── contracts/     # Input/output schemas (Zod)
│   │   ├── middlewares/   # Middleware (db provider, auth)
│   │   ├── routers/       # Handler implementations
│   │   ├── context.ts     # Request context
│   │   ├── server.ts      # ORPC server instance
│   │   └── types.ts       # Type exports
│   └── db/
│       ├── schema/        # Drizzle table definitions
│       └── index.ts       # Database instance
├── env.ts                 # Environment variable validation
├── router.tsx             # Router configuration
├── routeTree.gen.ts       # Auto-generated (DO NOT EDIT)
└── styles.css             # Tailwind entry
```

## ORPC Pattern

### 1. Define Contract (`src/server/api/contracts/feature.contract.ts`)
```typescript
import { oc } from '@orpc/contract'
import { createSelectSchema } from 'drizzle-zod'
import { z } from 'zod'
import { featureTable } from '@/server/db/schema'

const selectSchema = createSelectSchema(featureTable)

export const list = oc.input(z.void()).output(z.array(selectSchema))
export const create = oc.input(insertSchema).output(selectSchema)
```

### 2. Implement Router (`src/server/api/routers/feature.router.ts`)
```typescript
import { ORPCError } from '@orpc/server'
import { db } from '../middlewares'
import { os } from '../server'

export const list = os.feature.list.use(db).handler(async ({ context }) => {
  return await context.db.query.featureTable.findMany()
})
```

### 3. Register in Index Files
```typescript
// src/server/api/contracts/index.ts
import * as feature from './feature.contract'
export const contract = { feature }

// src/server/api/routers/index.ts
import * as feature from './feature.router'
export const router = os.router({ feature })
```

### 4. Use in Components
```typescript
import { useSuspenseQuery, useMutation } from '@tanstack/react-query'
import { orpc } from '@/client/orpc.client'

const { data } = useSuspenseQuery(orpc.feature.list.queryOptions())
const mutation = useMutation(orpc.feature.create.mutationOptions())
```

## Database Schema (Drizzle)

```typescript
import { pgTable, text, timestamp, uuid } from 'drizzle-orm/pg-core'
import { sql } from 'drizzle-orm'

export const myTable = pgTable('my_table', {
  id: uuid().primaryKey().default(sql`uuidv7()`),
  name: text().notNull(),
  createdAt: timestamp({ withTimezone: true }).notNull().defaultNow(),
  updatedAt: timestamp({ withTimezone: true }).notNull().defaultNow().$onUpdateFn(() => new Date()),
})
```

## Code Style

### Formatting (Biome)
- **Indent**: 2 spaces
- **Quotes**: Single `'`
- **Semicolons**: Omit (ASI)
- **Arrow parens**: Always `(x) => x`

### Imports
Biome auto-organizes:
1. External packages
2. Internal `@/*` aliases
3. Type imports (`import type { ... }`)

```typescript
import { createFileRoute } from '@tanstack/react-router'
import { z } from 'zod'
import { db } from '@/server/db'
import type { ReactNode } from 'react'
```

### TypeScript
- `strict: true`
- `noUncheckedIndexedAccess: true` - array access returns `T | undefined`
- Use `@/*` path aliases (maps to `src/*`)

### Naming
| Type | Convention | Example |
|------|------------|---------|
| Files (utils) | kebab-case | `auth-utils.ts` |
| Files (components) | PascalCase | `UserProfile.tsx` |
| Components | PascalCase arrow | `const Button = () => {}` |
| Functions | camelCase | `getUserById` |
| Types | PascalCase | `UserProfile` |

### React
- Use arrow functions for components (Biome enforced)
- Use `useSuspenseQuery` for guaranteed data
- Let React Compiler handle memoization (no manual `useMemo`/`useCallback`)

## Environment Variables

```typescript
// src/env.ts - using @t3-oss/env-core
import { createEnv } from '@t3-oss/env-core'
import { z } from 'zod'

export const env = createEnv({
  server: {
    DATABASE_URL: z.string().url(),
  },
  clientPrefix: 'VITE_',
  client: {
    VITE_API_URL: z.string().optional(),
  },
})
```

## Critical Rules

**DO:**
- Run `bun fix` before committing
- Use `@/*` path aliases
- Include `createdAt`/`updatedAt` on all tables
- Use `ORPCError` with proper codes

**DON'T:**
- Use `npm`, `npx`, `node`, `yarn`, `pnpm` — always use `bun` / `bunx`
- Edit `src/routeTree.gen.ts` (auto-generated)
- Use `as any`, `@ts-ignore`, `@ts-expect-error`
- Commit `.env` files
- Use empty catch blocks