Run a code review agent, and ask it to identify issues. For each issue, run multiple independent agents to perform independent verification of this issue. There will always be some that concur and some that disagree. But the probability distributions are vastly different for real issues vs hallucinations. If it is a real issue they are more likely to happen upon it. If it is a hallucination, they are more likely to discover the inconsistency on fresh examination.

This is NOT the same as asking “are you sure?” The sycophantic nature of LLMs would make them biased on that. But fresh agents with unbiased, detached framing in the prompt will show behavior that is probabilistically consistent with the underlying truth. Consistent enough for teasing out signal from noise with agent orchestration.