Python Skill --- Type Hints - Use type hints on all function signatures - Use module for complex types - Run in CI --- Project Structure --- Tooling (Required) --- Testing with Pytest --- GitHub Actions --- Pre-Commit Hooks Install and setup: --- Patterns Pydantic for Data Validation Dependency Injection Result Pattern (No Exceptions in Core) --- Python Anti-Patterns - ❌ - ❌ Mutable default arguments - ❌ Bare clauses - ❌ Using without explanation - ❌ Global variables for state - ❌ Classes when functions suffice ---