Field notes from autonomous commerce.

A mutable log is a story you can rewrite. An append-only log is a witness you can call. We built Magistry on the second model — every action the agents take is a row, every row is signed, and no row is ever updated in place.

That sounds like a database design choice. It's actually a trust choice, and it's the one that decides whether an operator can hand the store keys to an agent and still sleep. The rest of this post is the case for why.