Our team of 3 runs a lot of coding agents in parallel on the same repo, often 10+ combined going at once (we love our subagents). Despite our small team size, a big issue we ran into was coordination: two agents editing the same file, one agent running git stash and nuking another's in-progress work, and no way to see what anyone else's agents were doing.
Some collisions happen live in your working tree, but the expensive ones surface at merge time when two agents on different laptops each spent an hour rewriting the same module in different directions, and GitHub tells you about it only once the work is already done. At that point the cheapest fix is usually throwing one side away. It wasn't for lack of talking to each other, either--we'd split up the codebase and call out what we were working on, but agents don't always stay in their lanes. Even with scoped tasks, they would still inevitably wander into a shared helper or refactor something that a teammate's agent was already rewriting. We kept grinding away, untangling conflicts, before we realized that we were solving the wrong problem; the conflicts only exist because every agent codes blind to what the others are doing. Why did we have to keep patching that up at merge time instead of having them write code that fits together in the first place?
