PEP 723 was incorporated (with modifications) into the official Python packaging specifications: https://packaging.python.org/en/latest/specifications/inline...

I don't think running with uv vs uvx imposes any extra limitations on how you specify dependencies. You should either way be able to reference dependencies not just from PyPi but also by git repo or local file path in a [tool.uv.sources] table, the same as you would in a pyproject.toml file.