FastAPI CRUD Generator

Purpose

Auto-scaffold complete CRUD endpoints for SQLModel entities with pagination, validation, error handling, and proper session management.

Core Rules

1. •Context7 First: Query /websites/fastapi_tiangolo and /websites/sqlmodel_tiangolo for latest patterns
2. •uv Only: Never suggest pip commands
3. •Async Pattern: All operations use async def with proper session handling
4. •Type Safety: Use Python 3.10+ union types (int | None) and Annotated
5. •Response Models: Separate Create, Update, Public schemas

Workflow

1. •

   Analyze Target: Identify SQLModel entity to scaffold

2. •

   Query Docs: Fetch Context7 patterns for FastAPI + SQLModel CRUD

3. •

   Generate Schemas:

   python

   class TodoBase(SQLModel):
       title: str = Field(max_length=200, index=True)
       description: str | None = None
   
   class TodoCreate(TodoBase):
       pass
   
   class TodoUpdate(SQLModel):
       title: str | None = None
       description: str | None = None
       status: TodoStatus | None = None
   
   class TodoPublic(TodoBase):
       id: int
       status: TodoStatus
       created_at: datetime
   

4. •

   Generate Endpoints:

   • •POST /{resource}/ - Create with validation
   • •GET /{resource}/ - List with pagination (offset, limit ≤100)
   • •GET /{resource}/{id} - Get by ID with 404 handling
   • •PATCH /{resource}/{id} - Partial update with model_dump(exclude_unset=True)
   • •DELETE /{resource}/{id} - Soft or hard delete
5. •

   Add Dependencies:

   python

   SessionDep = Annotated[Session, Depends(get_session)]
   

6. •

   Include Error Handling:

   • •404 for not found
   • •422 for validation errors
   • •Proper session commit/rollback

Output Format

• •Complete router file with all 5 CRUD operations
• •Includes imports, schemas, and endpoints
• •Ready to integrate into existing FastAPI app

Example Usage

User: "Generate CRUD for the Todo model" Action: Query Context7 → Generate TodoCreate, TodoUpdate, TodoPublic → Create 5 endpoints → Return complete code

Quality Checks

• •✓ All endpoints use SessionDep
• •✓ Pagination on list (default limit=100, max=100)
• •✓ HTTPException for 404 errors
• •✓ model_validate() for create
• •✓ model_dump(exclude_unset=True) for update
• •✓ session.refresh() after mutations