By agent: engineer allowed-tools:
- Read
- Bash
- Grep
- Glob context: fork description: Idiomatic Python 3.12+ development. Use when writing Python code, CLI tools, scripts, or services. Emphasizes stdlib, type hints, uv/ruff/pyright toolchain, and minimal dependencies. NOT for Go, TypeScript, or shell-only tasks. name: writing-python user-invocable: false
Python Development
Use this only for Python 3.12+ code. Keep language-agnostic rules out of this skill.
Read First
Read principles.md before generating or changing Python code.
Core Rules
- Prefer existing project patterns over these defaults.
- Inspect the project Python target before using 3.12-only syntax.
- Prefer stdlib and existing dependencies before adding packages.
- Validate untyped boundary input before it spreads.
Conditional References
- patterns.md — read for module design, typing, async, config, file I/O, and error patterns.
- cli.md — read before writing or changing Python CLIs.
- testing.md — read before adding or reshaping Python tests.
Verification
Run project-configured tests, lint, format, and type checks. Prefer pytest, ruff, and pyright when present.
If a tool is not configured, say so and run the closest available gate. If a check fails, diagnose the cause, make a targeted fix, and rerun the relevant check.
Python-Specific Failure Cases
- No clear project root: locate
pyproject.tomlbefore editing or choosing commands. - Unknown Python target: inspect
pyproject.toml,.python-version, CI, or lockfiles before using 3.12-only syntax. - Type checker reports missing attributes: check imports, package exports, and runtime shape before loosening types.
Final Response
Include:
- changed files
- checks run and results
- checks skipped with reasons
- remaining risks or follow-ups