While working on the GitHub adapter, a gateway that lets AI agents create pull requests on GitHub, the source_state field first looked like a small technical detail.
It was not the operation itself, or the target. It was only a reference to the state the agent had seen before proposing a change.
But after working through the write path, this field started to look less like metadata and more like part of the safety model. A proposed change is not only defined by what it wants to do. It is also defined by the state in which that proposal made sense.
This is easy to miss.
An agent can read a repository, produce a reasonable change, and submit a clean intent. Nothing about that has to be wrong. But while the agent is planning, the repository can move. A human can push a fix. Another workflow can update the same file. A branch can advance.
