Use when creating Python projects, managing dependencies, or running Python scripts. Covers uv package manager commands, best practices, and common patterns for modern Python development.
Modern Python project management using uv - the fast, Rust-powered package manager.
Use this skill when:
| Feature | uv | pip | Poetry |
|---|---|---|---|
| Speed | 10-100x faster | Baseline | 2-3x slower |
| Virtual envs | Automatic | Manual | Automatic |
| Lockfile |
| Cross-platform |
| None |
| Yes |
| Python version mgmt | Built-in | No | No |
| Dev dependencies | Groups | No | Yes |
uv init # Create app project
uv init --package # Create package (src/ layout)
uv init --lib # Create library
uv add requests # Add dependency
uv add -d pytest # Add dev dependency
uv add 'requests>=2.28' # With version constraint
uv remove requests # Remove dependency
uv lock --upgrade # Update all dependencies
uv run python main.py # Run script in project env
uv run pytest # Run tools with dependencies
uvx ruff check . # Run standalone tool (isolated)
uv sync # Sync env with lockfile
uv sync --all-groups # Include all dependency groups
uv python install 3.11 # Install Python version
uv python pin 3.11 # Pin project to version
uv runWrong - bypasses project environment:
python main.py
pytest
Correct - uses project environment:
uv run python main.py
uv run pytest
uv run vs uvx| Command | Use For |
|---|---|
uv run pytest | Tools that need your project code |
uvx ruff check | Standalone tools (linters, formatters) |
Gotcha: uvx pytest won't see your project code!
uv creates this automatically:
my-project/
├── .venv/ # Auto-created, git-ignored
├── .python-version # Python version pin
├── pyproject.toml # Project config
├── uv.lock # Deterministic lockfile (commit this!)
└── src/ # Source code (if --package)
# pyproject.toml
[project]
dependencies = ["requests", "click"]
[dependency-groups]
dev = ["pytest", "black", "ruff"]
docs = ["sphinx"]
test = ["pytest-cov"]
uv add -d pytest # Add to dev group
uv add --group docs sphinx # Add to named group
uv sync --group docs # Install specific group
uv sync --all-groups # Install all groups
references/commands.md - Complete command referencereferences/workflows.md - Common workflows and patternsreferences/gotchas.md - Important gotchas and troubleshootinguv init my-project
cd my-project
uv add requests click
uv add -d pytest black ruff
uv run python -c "print('Ready!')"
git clone repo
cd repo
uv sync --all-groups # Install from lockfile
uv run pytest # Run tests
uv lock --upgrade # Update all
uv lock --upgrade-package requests # Update specific
uv sync # Apply updates
rm -rf .venv uv.lock
uv sync
| File | Commit? | Why |
|---|---|---|
pyproject.toml | Yes | Project definition |
uv.lock | Yes | Reproducible environments |
.python-version | Yes | Python version consistency |
.venv/ | No | Local environment |