| name | dev-python |
| description | Phase 5 implementation in Python — language idioms, tooling, and project layout. Composes with a component skill (dev-be/dev-cli/dev-batch). Use when: the stack is Python, implementing a component skill in Python, or setting Python tooling (venv, packaging) and layout. |
One-Liner
The Python language layer (idioms, tooling, layout) that composes under a component skill — the component owns what, this owns how in Python.
Use with a component skill (e.g. dev-be for a service, dev-batch for a job) — the component
skill says what to build; this says how in Python. Follow
../../resources/conventions/python.md.
Delegate craft depth to the expert. For real Python idioms, type-system, async, packaging, and
test patterns, load and follow the vendored python-pro expert (see
../../resources/expert-skills-map.md). This skill keeps
owning the harness wiring (persona, conventions, handoff, gates); python-pro supplies the depth.
Setup & tooling
- Virtualenv / the project's manager (uv/poetry/pip); pin dependencies.
- Type hints on public functions;
mypy/pyright clean.
- Lint/format:
ruff + black — must pass before review.
- Test runner:
pytest; test_*.py; fixtures over setup duplication.
Idioms
- Raise specific exceptions; never bare
except:; let unexpected errors propagate.
- Validate external input at boundaries (pydantic or dataclasses + checks).
- Prefer pure functions; dependency-inject side effects for testability.
- Use context managers for resources; avoid mutable default args.
Layout
- Package under
src/<pkg>/ (or the repo's layout); tests under tests/.
Hand off to check-code-review then the test types selected by check-test-strategy.
