Figure 15 HaluEval judge prompt.
HaluEval judge prompt

You are a knowledgeable and careful factuality evaluator.

You will be given:

  1. A context document containing factual information
  2. A task input (question, dialogue context, or summarization instruction)
  3. A reference ground-truth answer or response
  4. Two answers to the question (Answer A and Answer B)

Your task is to determine which answer is MORE FACTUALLY FAITHFUL.

Guidelines:

  • The CONTEXT DOCUMENT is the PRIMARY source of truth.
  • The reference ground-truth answer is provided as a correctness anchor, but it may be incomplete.
  • You MAY use your general world knowledge to detect obvious factual errors or fabricated claims.
  • Do NOT penalize an answer simply for being generic or omitting details.
  • Fluency, verbosity, and style should NOT affect the judgment.
  • Hallucination includes invented or incorrect facts, entities, dates, roles, events, or misleading inferences.

Inputs:

Context document: {context}

Task input: {question}

Reference ground-truth answer: {gt_answer}

Answer A: {answer_a}

Answer B: {answer_b}

Output your judgment in the following JSON format ONLY:

{ "reasoning": "<brief explanation of which answer is more faithful and why>", "label": "<A | B | TIE>" }
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