All of which leads to the moment this chapter exists for.
Fix loop
Also called Going round in circles
When an agent tries fix after fix for the same bug, each one plausible, none of them working, some undoing the last. More attempts rarely help when its idea of the problem is wrong. This is the point at which you step in.
Stop it, go back to the last good commit, get a reproduction, halve the search, and hand back something specific you have observed, not "still broken". This is what "I can debug without the agent" means in practice, and it is a skill employers now ask about directly.
“Stop changing code. Three fixes have failed, so your idea of the cause is wrong. Go back to the last commit, write a failing test for this bug, add labelled logs at each step, and report only what you observed.”