name: code-style description: Python code style and formatting standards using Ruff. Use when writing or reviewing Python code.

Python Code Style

Formatting

• Use Ruff for formatting (ruff format .)
• Indentation: 4 spaces
• Max line length: 120 characters
• Use trailing commas in multi-line collections

Naming Conventions

• Functions and variables: snake_case
• Classes: PascalCase
• Constants: UPPER_SNAKE_CASE
• Private members: _leading_underscore
• Module files: snake_case.py

Type Hints

• Required for all function parameters and return types
• Use Optional[T] or T | None for nullable types
• Use list[T], dict[K, V] (lowercase) for Python 3.10+

Docstrings

• Use Google-style docstrings
• Required for all public functions, classes, and modules
• Include Args, Returns, and Raises sections

Example:

def calculate_total(items: list[Item], discount: float = 0.0) -> float:
    """Calculate the total price of items with optional discount.

    Args:
        items: List of items to calculate total for.
        discount: Discount percentage to apply (0.0 to 1.0).

    Returns:
        The total price after discount.

    Raises:
        ValueError: If discount is not between 0 and 1.
    """

Imports

• Sort with Ruff (replaces isort)
• Group: stdlib, third-party, local
• Use absolute imports for clarity
• Avoid wildcard imports (from x import *)

Commands

• Format: ruff format .
• Lint: ruff check .
• Fix: ruff check --fix .