Glossary · Evaluation & safety
Hallucination
Generated content that is false, unsupported by the available evidence, or inconsistent with the task's source of truth. It can arise even when the output is fluent and the model is not attempting to deceive.
Why it matters
You usually cannot inspect whether a statement existed in training data, so production checks should focus on support, correctness, and traceability.
In practice
Require cited evidence for factual answers and evaluate whether each citation actually supports the associated claim.
Common confusion
A hallucination is an output-quality failure, not a diagnosis of model intent.
Related terms
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