python

name	python
description	Use when: write or review idiomatic, typed, well-structured Python that is easy to test and maintain.

Goal: clear, typed Python that fails loudly and tests easily.

Use for:

• new modules, scripts, or services in Python
• reviewing code for idiom, typing, and structure
• tightening loose, untyped, or side-effect-heavy code

Workflow:

1. Add type hints at function and module boundaries.
2. Prefer pure functions; isolate I/O and side effects.
3. Use dataclasses or pydantic for structured data, not dicts.
4. Handle errors with specific exceptions; avoid bare except.
5. Manage resources with context managers (with-blocks).
6. Verify with pytest, ruff/flake8, and a type checker (mypy/pyright).

Idioms:

• comprehensions and generators over manual loops
• pathlib over os.path string juggling
• f-strings for formatting
• enumerate/zip instead of index bookkeeping
• prefer the standard library before adding a dependency

Rules:

• type the boundaries; let inference handle locals
• never catch Exception just to silence it
• pin dependencies and use a virtualenv or uv
• keep functions small and single-purpose; test behavior