Hallucination

Hallucination is the safety-critical failure mode where a language model generates plausible-sounding but factually incorrect or entirely fabricated content. From a safety perspective, hallucinations are dangerous because they are hard to detect — confident phrasing and grammatical fluency give no signal of accuracy. They are particularly harmful in high-stakes domains such as medicine, law, and finance. Mitigations include retrieval augmentation, output verification layers, and uncertainty quantification.