python-development

name	python-development
description	Covers Python 3.12+ with FastAPI, Pydantic, async patterns, pytest, SQLAlchemy, and uv toolchain. Use when building Python services, APIs, data models, or tests. Provides patterns for modern Python development. Not for schema design (use database-design), infrastructure (use infrastructure-management), or frontend code (use typescript-development).
user-invocable	false
allowed-tools	Read, Write, Edit, Bash, Glob, Grep
version	0.3.1

Python Development

Modern Python 3.12+ development with FastAPI ecosystem.

Contents

• Critical Rules
• Verification
• Quick Reference
• Topics
• Stack Overview

Critical Rules

Always

• Use async def for I/O-bound operations
• Use Pydantic models for external input validation
• Use pathlib.Path for file operations
• Run mypy in CI/CD pipeline

Never

• Block the event loop with sync I/O in async code
• Use mutable default arguments (def foo(items=[]))