uv Skill

Extremely fast Python package and project manager by Astral (Ruff creators).

Overview

uv is a single tool that replaces:

• pip/pip-tools - Package installation and dependency resolution
• virtualenv/venv - Virtual environment creation
• pyenv - Python version management
• pipx - Tool installation and execution
• poetry/pdm - Project and dependency management
• twine - Package publishing

Key Features:

• 10-100x faster than pip
• Universal lockfile (uv.lock) for reproducible builds
• Automatic Python version management
• Built-in tool execution (uvx)
• PEP 723 inline script dependencies
• Drop-in pip compatibility

Quick Reference

Quick Start

Installation

# macOS/Linux
curl -LsSf https://astral.sh/uv/install.sh | sh

# Windows
powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"

# Via pip/pipx
pipx install uv
pip install uv

# Homebrew
brew install uv

Shell Completion

# Bash
echo 'eval "$(uv generate-shell-completion bash)"' >> ~/.bashrc

# Zsh
echo 'eval "$(uv generate-shell-completion zsh)"' >> ~/.zshrc

# Fish
echo 'uv generate-shell-completion fish | source' > ~/.config/fish/completions/uv.fish

Essential Commands

1. Starting a Project

# Create new project
uv init my-project          # Application (default)
uv init --lib my-library    # Library (src layout, build backend)
uv init --app my-app        # Explicit application

# Set Python version
uv python pin 3.12          # Creates .python-version

# Install Python if needed
uv python install 3.12

2. Managing Dependencies

# Add packages
uv add requests flask       # Production dependencies
uv add --dev pytest ruff    # Development dependencies
uv add --group test pytest  # Specific dependency group
uv add --optional api flask # Optional extra
uv add "httpx>=0.20"        # With version constraint

# Remove packages
uv remove requests
uv remove --dev pytest

# Update packages
uv lock --upgrade                    # All packages
uv lock --upgrade-package requests   # Single package

# View dependencies
uv tree                     # Full tree
uv tree --depth 2           # Limited depth

3. Syncing Environment

# Install all dependencies
uv sync                     # Default (includes dev)
uv sync --locked            # CI/production (strict)
uv sync --frozen            # Don't update lockfile
uv sync --no-dev            # Exclude dev dependencies
uv sync --all-extras        # Include optional extras

4. Running Code

# Run in project environment
uv run python script.py
uv run pytest
uv run flask run

# Run with temporary dependency
uv run --with pandas script.py

# Run tools without installing (uvx)
uvx ruff check .
uvx black --check .
uvx --from httpie http https://example.com

5. Python Version Management

# Install Python versions
uv python install           # Latest version
uv python install 3.12      # Specific version
uv python install 3.11 3.12 3.13  # Multiple

# List versions
uv python list
uv python list --only-installed

# Pin version
uv python pin 3.12          # Project (.python-version)
uv python pin --global 3.12 # User default

# Find Python
uv python find
uv python find ">=3.11"

6. Virtual Environments

# Create (usually automatic)
uv venv                     # Creates .venv
uv venv my-env              # Custom name
uv venv --python 3.12       # Specific Python

# Activate (optional - uv run auto-detects)
source .venv/bin/activate   # macOS/Linux
.venv\Scripts\activate      # Windows

7. Global Tools

# Install tools globally
uv tool install ruff
uv tool install "ruff==0.5.0"
uv tool install --python 3.12 mypy

# Manage tools
uv tool list
uv tool upgrade ruff
uv tool upgrade --all
uv tool uninstall ruff

# Setup PATH
uv tool update-shell

Scripts with Inline Dependencies (PEP 723)

# Initialize script with metadata
uv init --script example.py --python 3.12

# Add dependencies to script
uv add --script example.py requests rich

# Run script (dependencies auto-installed)
uv run example.py

Script format:

# /// script
# requires-python = ">=3.12"
# dependencies = [
#   "requests<3",
#   "rich",
# ]
# ///

import requests
from rich impo

...