Stop Returning Text from RAG: The Typed Answer Contract That Prevents Hallucination

To prevent hallucinations in Retrieval-Augmented Generation (RAG) systems, models should be compelled to return structured, typed answers instead of plain text. This method enforces a "typed answer contract," where a predefined schema forces the model to fill specific fields like amounts, dates, and tables using only the provided source documents. Each piece of data returned must be accompanied by a precise citation, and the model also provides self-assessment feedback, such as its confidence level or whether the complete answer was found. By constraining the model's output to this verifiable structure, the system effectively eliminates the opportunity for invention and creates a more reliable, checkable process.