I'm curious to know what's everyone custom solution to this problem ? Before AI and with AI.

It was already a problem for me before agentic AI coding : multiple developers can work on overlapping code and you always need someone to merge everything properly. Even if the overlap is very small it does add a burden to development. Not an issue anymore in 95% of cases if that person uses AI to solve conflicts, but now that "others developers" are swarm of AI agents, this problem isn't trivial to solve.

We’ve been taking a different path to this author, albeit to solve a similar problem. Rather than thinking agents diminish the value of code ownership, we think it stays level or potentially increases. To that end, teams are responsible for managing the agent model, harness, instructions, local skills or other config for their areas. When work needs to be done across areas we allow it, but via an orchestration layer where agents operate via adversarial negotiation, with escalations and explanations to engineers when decisions are hard to make.

We find giving the agents independent remits makes them significantly better at challenging problematic requirements, because they aren’t all automatically aligned on the same goals.

The agents from each area then having queues and messaging subsystems to coordinate their work when there are multiple streams happening, although concurrency is less of an issue than we expected. Generally will detect and flag competing requirements, which has saved us from some subtle issues. We don’t always require code owners to review every PR in their area, but they do at least always have a log of what work was done and why, which is separate from the noise of the parent work.

This does all work out a bit slower than just letting each agent get on with its job, but it’s working pretty well for us.

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