So far the history is a single line. The move that makes agents safe to run is letting it fork.
Branch
A name that points at one commit, and moves forward each time you commit on it. It lets you work on one thing without touching the main line. HEAD is git's marker for which branch you are on.
A branch is how you give an agent room to be wrong. If the work goes badly, you switch back and delete the branch, and the main line never knew. Since branches cost almost nothing, one for each task is a sensible default.
Say it to your agent
“Create a branch called fix/cart-rounding from main before you change anything. Work only on that branch. Don't merge it, and don't push to main.”