The worst coding agent failure is when it says “done” too early

I think the most annoying failure mode in coding agents is not when they clearly fail. Clear failure is easy to handle. The harder problem is when the agent says the task is done, the output looks reasonable, but there are still hidden issues: * tests were not really enough * edge cases were missed * files were changed unnecessarily * the fix created another bug * the code works only for the happy path * someone still has to review and clean everything up That creates a weird trust problem. You are no longer just asking: “Can the agent write code?” You are asking: “Can I trust when the agent says it is finished?” For people using coding agents regularly: How do you decide when the agent is actually done?