How to Prevent LLM Hallucinations with Guardrails (2026) A support bot tells a customer that worn shoes qualify for a full refund. The policy says the opposite. The answer reads fluently, cites the right document, and is wrong in exactly the detail that costs money. This hypothetical example illustrates one form of an LLM hallucination: not wild invention, but a small confident misread of a real source. Prompting the model to "be careful" does not fix it. A verification loop can catch some f...