Hallucination

A hallucination is a confident, fluent output that is factually wrong or unsupported by any real source — the model completing a plausible-sounding answer rather than admitting it doesn't know. It's not a bug that gets patched out; it's a structural property of how these models generate text, which is why grounding (RAG) and evals, not a better prompt, are the actual mitigations. A demo that never surfaces a hallucination almost always means the test set was too easy, not that the system is hallucination-free.

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