Well you can’t edit files while Xcode is building or the compiler will throw up, so I‘m wondering what you mean here. You can’t even run swift test in 2 agents at the same time, because swift serializes access for some reason.

Whenever I have more than 1 agent run Swift tests in a loop to fix things, and another one to build something, the latter will disturb the former and I need to cancel.

And then there’s a lot of work that can’t be parallelized, like complex git rebases - well you can do other things in a worktree, but good luck merging that after you‘ve changed everything in the repo. Codex is really really bad at git.