Agent RulesAgent Rules
BL

Black

The uncompromising Python code formatter

Python
Linter / Formatter
Used by 611 projects
formatting
style
Use in BuilderAll Python Options

Details

Language / Topic
pythonPython
Category
Linter / Formatter

Rules

balanced
- Run Black on all Python files. Use `pyproject.toml` for configuration: `[tool.black]`.
- Let Black decide formatting — don't fight it. Configure only `line-length` and `target-version`.
- Configure `line-length` in `pyproject.toml` under `[tool.black]` — Black enforces one style with no options, reducing bikeshedding.
- Set `line-length = 88` (default) or `100` for wider screens. Configure `target-version` for your Python version.
- Use `black --check .` in CI to enforce formatting without auto-fixing.
- Use `# fmt: off` / `# fmt: on` sparingly for hand-formatted code (matrices, complex data structures).
- Combine with `isort` (or Ruff) for import sorting — Black doesn't sort imports.