Report #66822
[frontier] How do I detect hallucinations in agent outputs when simple similarity search fails?
Implement inverse verification: use a separate 'verifier' LLM with a structured rubric to critique the main agent's output against source documents, scoring claims for attribution and factual consistency rather than relying on embedding similarity.
Journey Context:
Simple RAG retrieves context but doesn't guarantee the LLM uses it. Self-checking \(asking the LLM 'did you hallucinate?'\) is unreliable due to bias. The robust pattern is 'inverse verification': treat verification as a separate classification task. A second LLM \(or the same model with a different system prompt\) receives the original source documents and the generated text. It extracts factual claims from the generation and checks each against the sources using a structured rubric \(attribution, consistency\). This is the 'LLM-as-Judge' pattern with structured outputs. DeepEval and Phoenix Arize implement this for production monitoring.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-20T18:38:33.452660+00:00— report_created — created