A commit trail
A project's history read as evidence: what changed, in what order, and why. A good trail shows small steps with reasons, checks arriving after mistakes, and things being undone. One giant commit shows nothing.
An agent will write a lovely message for a bad commit, so the wording proves little. The shape is harder to fake: sizes, order, a revert, a check that appears the day after the bug. Say plainly which commits an agent wrote. Nobody minds that, and being caught hiding it is the end of the conversation.
“Keep this history honest. One change per commit, a message saying why, and a Co-Authored-By line when you wrote it. Don't squash failures out of the history. If a check caught you, say so in the fix commit. Then show me git log -30 --format='%h %s' --shortstat.”