UV

UV is a fast Python package manager. Two modes:

Scripts vs Projects

Use scripts when:

• Single .py file
• Quick utility, one-off task
• No shared dependencies across files

Use projects when:

• Multiple files, modules, or packages
• Team collaboration
• Need reproducible environments
• Building a library or application

Scripts

Standalone Python files with inline dependencies (PEP 723).

#!/usr/bin/env -S uv run --script
# /// script
# requires-python = ">=3.12"
# dependencies = ["requests", "rich"]
# ///

import requests
from rich import print

Run: uv run script.py

See references/scripts.md for full guide.

Projects

Structured Python with pyproject.toml and lockfile.

uv init myproject
cd myproject
uv add requests
uv run python main.py

Key files:

• pyproject.toml - metadata and dependencies
• uv.lock - exact versions for reproducibility
• .python-version - Python version

See references/projects.md for full guide.

Common Patterns

uv run pytest                     # Run in project env
uv add --dev pytest               # Dev dependency
uvx ruff check .                  # One-off tool execution
uv run --with rich script.py      # Script with ad-hoc dep