I wrote a tool in this space as well, precious (https://github.com/houseabsolute/precious). It's odd to me that these tools are often talked about with such a focus on Git hooks. Yes, that is definitely one use case, but I also want to run this sort of thing in CI to check PRs, and I _also_ want to run it locally to apply _pretty-printing_ to new code, rather than just having it check the code that I wrote.

I think hk does do all those things, but it's a bit obscured by the focus on Git hooks in the docs. But the docs are also still in a super early state, so maybe that will be fleshed out more in the future.