Backend Development

Use when creating or modifying FastAPI endpoints, Pydantic schemas, database operations, LLM integrations, or Python service logic.

Before Writing Code

1. Read docs/agent/architecture/backend-guide.md for architecture
2. Read docs/agent/apis/front-end-apis.md for API contracts
3. Read docs/agent/llm-integration.md for LLM patterns
4. Check existing code in the relevant directory first

Non-Negotiable Rules

1. All functions MUST have type hints - no exceptions
2. Use copy.deepcopy() for mutable defaults
3. Log detailed errors server-side, return generic messages to clients
4. Use asyncio.Lock() for shared resource initialization
5. Pass API keys directly to litellm via api_key=, never os.environ