What is Hallucination?
Verified 5 August 2026
Retrieval reduces hallucination by grounding answers in documents, but it does not eliminate it — an agent given twelve copies of one unverified claim will treat it as well established, because repetition looks like corroboration.
Two structural defences help more than prompt engineering. Counting distinct asserting hosts distinguishes independently reported facts from echoes. Answering "why is this URL absent" prevents the agent inferring non-existence from an empty result set.
How unlob handles this: corroborate
Common questions
What is Hallucination?
A hallucination is a confident, plausible model output that is not supported by any source.
How does Hallucination work in practice?
Two structural defences help more than prompt engineering. Counting distinct asserting hosts distinguishes independently reported facts from echoes. Answering "why is this URL absent" prevents the agent inferring non-existence from an empty result set.
See it working
The free tier is 10,000 requests a month with no card — enough to test any of this against your own queries.