Description
Guide for using uv, the Python package and project manager. Use this when working with Python projects, scripts, packages, or tools.
SKILL.md
uv
uv is an extremely fast Python package and project manager. It replaces pip, pip-tools, pipx, pyenv, virtualenv, poetry, etc.
When to use uv
Always use uv for Python work, especially if you see:
- The
uv.lockfile - uv headers in
requirements*files, e.g., "This file was autogenerated by uv"
Don't use uv in projects managed by other tools:
- Poetry projects (identifiable by
poetry.lockfile) - PDM projects (identifiable by
pdm.lockfile)
Choosing the right workflow
Scripts
Use when: Running single Python files and standalone scripts.
Key commands:
uv run script.py # Run a script
uv run --with requests script.py # Run with additional packages
uv add --script script.py requests # Add dependencies inline to the script
Projects
Use when: There is a pyproject.toml or uv.lock
Key commands:
uv init # Create new project
uv add requests # Add dependency
uv remove requests # Remove dependency
uv sync # Install from lockfile
uv run <command> # Run commands in environment
uv run python -c "" # Run Python in project environment
uv run -p 3.12 <command> # Run with specific Python version
Tools
Use when: Running command-line tools (e.g., ruff, ty, pytest) without installation.
Key commands:
uvx <tool> <args> # Run a tool without installation
uvx <tool>@<version> <args> # Run a specific version of a tool
Important:
uvxruns tools from PyPI by package name. This can be unsafe - only run well-known tools.- Only use
uv tool installonly when specifically requested by the user.
Pip interface
Use when: Legacy workflows with requirements.txt or manual environment
management, no uv.lock present.
Key commands:
uv venv
uv pip install -r requirements.txt
uv pip compile requirements.in -o requirements.txt
uv pip sync requirements.txt
# Platform independent resolution
uv pip compile --universal requirements.in -o requirements.txt
Important:
- Don't use the pip interface unless clearly needed.
- Don't introduce new
requirements.txtfiles. - Prefer
uv initfor new projects.
Migrating from other tools
pyenv → uv python
pyenv install 3.12 → uv python install 3.12
pyenv versions → uv python list --only-installed
pyenv local 3.12 → uv python pin 3.12
pyenv global 3.12 → uv python install 3.12 --default
pipx → uvx
pipx run ruff → uvx ruff
pipx install ruff → uv tool install ruff
pipx upgrade ruff → uv tool upgrade ruff
pipx list → uv tool list
pip and pip-tools → uv pip
pip install package → uv pip install package
pip install -r req.txt → uv pip install -r req.txt
pip freeze → uv pip freeze
pip-compile req.in → uv pip compile req.in
pip-sync req.txt → uv pip sync req.txt
virtualenv .venv → uv venv
Common patterns
Don't use pip in uv projects
# Bad
pip install requests
# Good
uv add requests
Don't run python directly
# Bad
python script.py
# Good
uv run script.py
# Bad
python -c "..."
# Good
uv run python -c "..."
# Bad
python3.12 -c "..."
# Good
uvx python@3.12 -c "..."
Don't manually manage environments in uv projects
# Bad
python -m venv .venv
source .venv/bin/activate
# Good
uv run <command>
Documentation
For detailed information, read the official documentation:
The documentation links to specific pages for each of these workflows.