lang-pythonlisted

# Python — idiomatic & safe The language lens for Python work. Backs the build agents at Stage 6. Honors `_shared/vibegod-principles.md` (simplicity, surgical, typed/no-`Any`-by-default, no silent error-swallowing, consistency, cost-awareness). Defer security depth to `secure-coding` and test discipline to `test-driven-development`. ## Fits in the pipeline Stage 6 (Build): write code to this standard. Stage 7 (per-feature QA): the code-quality-reviewer + security-engineer lenses check it against this skill. Priority: **user > skills > default.** ## Style & layout - Python **3.11+**. `src/` layout package, tests in `tests/`. PEP 8 via tooling, not by hand. - Type hints on every public function signature and dataclass/model field. Prefer `dataclass`/`pydantic` models over loose dicts. Use modern syntax: `X | None`, `list[str]`. - Small pure functions; modules grouped by feature. No wildcard imports. ## Toolchain (canonical) - **Env/deps:** `uv` (preferred) or Poetry; committed lockfile. Never install into system Python. - **Lint/format:** `ruff check` + `ruff format` (or black). CI runs both. - **Type-check:** `mypy --strict` or `pyright`. Treat type errors as build failures; avoid `Any` and bare `# type: ignore` (scope and justify them). - **Test:** `pytest` (+ `pytest-cov`). Fixtures over setup boilerplate. ## Types & boundary validation - Validate all external input (HTTP bodies, query/env, file/JSON, message payloads) with **pydantic v2** models at the boundary;