Uv Python Scripts

uv for Python

Use uv for everything Python — running scripts, managing deps, virtualenvs, and projects. Don't use pip, pip-tools, poetry, pipenv, venv, or python -m pip directly.

Decision: single script vs. project

• One file, no shared state with other code → single script with PEP 723 inline metadata + uv shebang. Fully self-contained, no pyproject.toml.
• Anything bigger (multiple modules, importable package, tests, CLI entry point) → uv project with pyproject.toml.

Single-file script template

#!/usr/bin/env -S uv run --script
# /// script
# requires-python = ">=3.12"
# dependencies = [
#   "httpx",
#   "rich",
# ]
# ///
"""Short description of what this script does."""

import httpx
from rich import print

def main() -> None:
    r = httpx.get("https://example.com")
    print(r.status_code)

if __name__ == "__main__":
    main()

After writing, chmod +x script.py so it runs directly. The shebang #!/usr/bin/env -S uv run --script works on macOS and Linux; -S is required so env accepts the multi-word argument. uv resolves and caches deps on first run.

To add a dep to an existing script: uv add --script script.py <pkg>.

Project template (multi-file)

Initialize:

uv init <name>          # creates pyproject.toml, .python-version, src layout, README
cd <name>
uv add <runtime-deps>
uv add --dev pytest ruff

Run things via uv (it manages the venv automatically):

uv run python -m mypkg
uv run pytest
uv run ruff check

Commit pyproject.toml and uv.lock. Don't commit .venv/.

Command translation

Don't

• Don't write requirements.txt for new work — use pyproject.toml or PEP 723 inline metadata.
• Don't create or activate a venv manually; uv run does it.
• Don't use a plain #!/usr/bin/env python3 shebang for scripts that have dependencies — those will break on machines without those deps installed globally. Use the uv shebang.
• Don't pin Python via python_requires in setup.py; use requires-python in pyproject or the script header.

If uv isn't installed

brew install uv (macOS) or curl -LsSf https://astral.sh/uv/install.sh | sh. Don't fall back to pip.