I'm currently experimenting with Devstral for my own local coding agent I've slowly built together. It's in many ways nicer than Codex in that 1) full access to my hardware so can start VMs, make network requests and everything else I can do, which Codex cannot and 2) it's way faster both in initial setup, working through things and creating a patch.

Of course, it still isn't at the same level as Codex itself, the model Codex is using is just way better so of course it'll get better results. But Devstral (as I currently use it) is able to make smaller changes and refactors, and I think if I evolve the software a bit more, can start making larger changes too.