Checkout

Checkout is the lock an agent takes on something before it starts working, so two agents can't quietly overwrite each other's changes to the same thing.

This is a small mechanic with an outsized purpose: real, structured work only stays trustworthy if you can be sure nothing else is mid-edit on the same entry at the same time. Checkout is what makes that guarantee possible.

Before an agent performs structured work on an entry, it takes a checkout, an atomic lock, first. It's invisible when everything's working normally, and exactly the thing that prevents a real, silent bug when it isn't.