modern-python

name	modern-python
description	Configures Python projects with modern tooling (uv, ruff, ty, pytest). Use when creating projects, writing scripts, or migrating from pip/Poetry/mypy/black.
license	MIT
metadata	{"author":"Trail of Bits (adapted)","version":"1.0.0","domain":"python","source":"trailofbits/skills/modern-python"}

Modern Python

Guide for modern Python tooling and best practices.

Knowledge Graph

• extends: [[backend-developer]]
• requires: []
• suggests: [[qa-tester]], [[devops-engineer]]
• conflicts: []
• moc: [[python-development-moc]]

Core Toolchain

Tool	Purpose	Replaces
uv	Package/dependency management	pip, virtualenv, pipx, pyenv
ruff	Linting AND formatting	flake8, black, isort
ty	Type checking	mypy, pyright
pytest	Testing with coverage	unittest

Anti-Patterns

Avoid	Use Instead
pip install	uv add + uv sync
requirements.txt	PEP 723 (scripts) or pyproject.toml (projects)
Poetry	uv (faster, simpler)
mypy / pyright	ty (faster, Astral team)
[project.optional-dependencies] for dev	[dependency-groups] (PEP 735)
Manual venv activation	uv run <cmd>

Decision Tree

What are you doing?
│
├─ Single-file script with deps?
│   └─ PEP 723 inline metadata
│
├─ New multi-file project?
│   └─ uv init → uv add → uv run
│
├─ New reusable package?
│   └─ uv init --package → full pyproject.toml
│
└─ Migrating existing project?
   └─ uv init --bare → uv add from existing deps

Quick Start

uv init myproject && cd myproject
uv add requests rich
uv add --group dev pytest ruff ty
uv run python src/myproject/main.py
uv run pytest
uv run ruff check .

pyproject.toml Template

[project]
name = "myproject"
version = "0.1.0"
requires-python = ">=3.11"

[dependency-groups]
dev = [{include-group = "lint"}, {include-group = "test"}]
lint = ["ruff", "ty"]
test = ["pytest", "pytest-cov"]

[tool.ruff]
line-length = 100
target-version = "py311"

[tool.ruff.lint]
select = ["ALL"]
ignore = ["D", "COM812", "ISC001"]

[tool.pytest]
addopts = ["--cov=myproject", "--cov-fail-under=80"]

Key Commands

Command	Description
uv add <pkg>	Add dependency
uv add --group dev <pkg>	Add dev dependency
uv sync --all-groups	Install all
uv run <cmd>	Run in venv
uv run --with <pkg> <cmd>	Run with temp dep
uv build	Build package

Checklist

• Use src/ layout
• requires-python = ">=3.11"
• ruff with select = ["ALL"]
• ty for type checking
• Test coverage ≥ 80%
• uv.lock in version control

---

Modern Python setup | Trail of Bits methodology