One Writer · Our tools assume one writer, and assume that writer is a human. Nothing computes what a change reads and writes at runtime, so the only known fix is brute force priced for organizations.

Six weeks ago I wrote The Test Suite Was the Incident: my test suite had grown a pile of shared data nobody owned, every pull request paid to rebuild it, and the resulting failures had nothing to do with the changes under review. That cost me about $180 in one night. I got a worse one, and it lasted three days. This post is not really about that, though. It’s about a property of our tooling that the three days made impossible to ignore. Nearly every layer of this assumes one writer, and assumes that writer is a human. Git hands you a conflict and waits. Code review assumes somebody reads. A migration sequence assumes somebody is assigning the order. Each of those protocols terminates in a person, which is fine while there is exactly one and they are one. That was invisible for forty years because nothing ever bound it at my scale. Agents break both halves at once: there are many of them, and not one of them is the person the protocol was waiting for. Git is the partial exception, and…