next question is who's allowed to change it and in what order? Two correct rights can still produce one wrong outcome. and last writer wins is not a consistency model. In this overlapping writer open claw issue describes a load modify save race. Two callers loads the same old state. Each changes a different record. The sil the second save silently erases the first. The user may see a dismissed commitment return or receive a duplicate follow-up. Neither writer is malformed. Both operations are locally correct. The missing boundary is civilization around the commit. The invariant is not no concurrency. That would be too slow and it would miss the point. You can fan out sub agents. Parallel reads are fine. Independent retrieval is fine. Many sessions can also run at once. The rule is narrower and simple. One ordered commit path for one mutable state boundary. This mechanism may be a Q, a mutx, a transaction or a lock. You can use locks or mutx across the sessions and cues or transactions within a session. Be conservative of the commit time and not across the whole system. Users do not see cues or locks. They see behavior. A last correction feels forgetful. A stuck lane feels dead. And completion before delivery feels confused. Ordering is a product feature because users experience ordering books as