All pyproject.toml requirements (the dependency version constraints published on pypi) shall be honored prior to uv transferring control to your app.

That wasn't clear to me. Thanks for pointing that out. I've tested it by replacing uvx streamlit with streamlit and it seems to work just as well.

You haven't cited any streamlit documentation that talks about a "run" verb which will locate and download a foobarbaz pypi package, and I certainly don't recall having come across such a thing.

streamlit run app.py is the default idiom AFAIK (source).

Please publish the URL of the GitHub repo where you are exploring these issues.

This seems to work now. Thanks a lot!