Hallucination
Beginner
When an AI model states something false with full confidence, such as a tool option that does not exist.
Novice
Fluent, confident model output that is wrong or made up: a tool option that doesn’t exist, a wrong signal name, an invented detail of a specification.
Expert
Common defenses are pasting trusted documents into the prompt (retrieval-augmented generation, RAG), running the output through tools that fail loudly on invalid commands, and checking against a reference. None removes it, so outputs are treated as unchecked drafts.