python-stylelisted

# Python Coding Style Guidelines ## Scope This skill governs **code written inside an already-bootstrapped Python project** — class design, test authoring, refactoring, code review, naming, imports, docstrings. Project bootstrap (flake.nix, direnv, `uv init`, initial `pyproject.toml` merge) belongs to the `nix-dev-init` skill. If the project is not yet bootstrapped, defer to `nix-dev-init` first and return here once `direnv allow` succeeds and the shell has `uv` on PATH. ### Why the split Keeping bootstrap out of this skill has two benefits: (1) when Claude is triggered to write or refactor Python code in an existing project, it does not read a long bootstrap procedure it does not need; (2) the nix `flake.nix` → `direnv` → `uv init` → `pyproject.toml` ordering is an invariant owned by `nix-dev-init` — duplicating a shortcut here would let it drift. ## Package Management - Use only `uv` for package management, don't use `pip` - Install dependencies using `uv sync` - Run tools using `uv run {tool}` - Baseline tooling dependencies belong in template-defined dependency groups, not ad hoc commands - Add project-specific dependencies using `uv add {package}` - Add project-specific tool dependencies using `uv add --group <group> {package}` - Upgrade pinned packages using `uv lock --upgrade-package {package}` - Prohibited: `uv pip install`, `uv add --dev`, `@latest` ## Directory Structure - Store production code including entry points in `./src` directory - Store test code i