There’s a bit of a bootstrap problem there in that Tox (and its dependencies) have to be installed first, unless your makefile is calling “uv run tox” or similar. Uv’s standalone nature makes it ideal for bootstrapping projects in a way that tox isn’t.

I like just or mise tasks as often my python projects contain many other language commands (SQL, docker, pnpm, etc ...).

Strong disagree on tox. I was all in on it back in 2020-2023 and I found it was a consistent source of headaches and complexity. Whenever we’d run into venv issues it was always tox, often passing or not passing some critical under-the-hood ENV var resulting in reproducibility errors that were difficult to immediately diagnose. It also blurs the line between env vars used to set up tox env and those you want set in your final test env.

We just use containers in CI instead now for matrix testing and it’s so much more clear what is going on with the test env.

It always could.

We do a lot more than that, e.g. how to cache distributions is not defined anywhere within PEPs (and should not be, since it’s a purely internal tool decision). But yes, it helps that uv implements the PEP for detached metadata, particularly during resolution.