Run two AI coding agents on the same repo and the first thing that breaks is not the code. It is coordination. Agent A starts refactoring auth. Agent B, running in parallel, has no idea and starts the same thing. Neither remembers what it did last session, because each one boots fresh with an empty context window. The usual fixes are worse than the problem: a state file in the repo pollutes every diff and conflicts on merge, and an external issue tracker means API tokens, rate limits, and ...