Something I’m constantly forgetting is how to declare scripts with pyproject.toml. This is a quick reference for me to come back to when I inevitably forget this again.

Let’s work with basic project structure:

.
|-- pyproject.toml
`-- foo
    |-- __init__.py
    |-- __main__.py
    `-- ...

The file __main__.py will be the function we want to run in the script:

def main():
    print("Hello from my app!")

if __name__ == "__main__":
    main()

Define the entry point under [project.scripts] in pyproject.toml:

[project]
name = "my-app"
version = "0.1.0"

[project.scripts]
foo = "foo.__main__:main" # Runs main() from foo/__main__.py

[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"

[tool.hatch.build.targets.wheel]
packages = ["foo"]

Now this can be executed with uv run foo if you’re using uv (which you should be in this age!), or using pip install -e . then calling foo