I think before AI was writing most of the code and with small teams the solution was probably just ownership and talking (and meetings about meetings). Things moved at a pace where it was more possible to have someone oversee this, though I agree on larger teams it has always been a problem. I think Foremerge solves that too even without agents but the manual overhead outweighs more of the cost that it does with agents. Even if you can use AI to resolve the conflicts at PR time, you need the right context and you've already burned through tokens building and now even more fixing. Scale that across 10's or 100's of agents and you have a mess of each one running in its own direction. The custom solution for us became one worktree per task, and before an agent writes a line of code they lease/commit their intent and scope into an immutable log and verify drift as the acceptance check...thats now Foremerge