# Chain-of-Verification Fact Check Prompt

> Draft an answer, generate verification questions, answer them independently, then revise, reducing factual errors.

Category: Prompt & Agent Patterns  
Tags: verification, hallucination, accuracy  
Setup time (estimate): 15 minutes  
Estimated cost: About 3-4x the tokens of a single answer (draft, questions, checks, final).  
Last verified: not yet independently verified

Based on Chain-of-Verification (Dhuliawala et al., 2023).

## Steps

1. **Baseline**: answer the question.
2. **Plan verifications**: list factual claims as questions.
3. **Execute independently**: answer each question *without* showing the draft (separate calls), ideally with retrieval/search.
4. **Revise**: rewrite the answer, dropping or correcting claims that failed verification.

## Prompts

```text
# Step 2
List each factual claim in the ANSWER as a standalone yes/no or short-answer question.
Return JSON: {"questions": ["..."]}
ANSWER: {{draft}}

# Step 4
Original question: {{question}}
Draft: {{draft}}
Verification results: {{qa_pairs}}
Rewrite the draft so it is consistent with the verification results.
Remove any claim that could not be verified. Do not add new unverified claims.
```

## Failure modes

- The model can 'verify' a wrong claim with the same wrong knowledge; pair with retrieval for facts.
- Verification questions that just restate the claim add cost without catching errors.
- Long drafts produce too many checks; cap the number of questions.