This works really well in my experience, but it does mean you need to have a working internet connection the first time you run the script.

  # /// script
  # dependencies = [
  #     "cowsay",
  # ]
  # ///
  import cowsay
  cowsay.cow("Hello World")

Then:

  uv run cowscript.py

It manages a disposable hidden virtual environment automatically, via a very fast symlink-based caching mechanism.

You can also add a shebang line so you can execute it directly:

  #!/usr/bin/env -S uv run --script
  #
  # /// script
  # dependencies = ["cowsay"]
  # ///
  import cowsay
  cowsay.cow("Hello World")

Then:

  chmod 755 cowscript
  ./cowscript