Skip to main content
Version: 2.0

Evaluate factual consistency

POST 
/v2/evaluate_factual_consistency
Supported API Key Type:
Query ServicePersonal

Evaluate the factual consistency of a generated text (like a summary) against source documents. This determines how accurately the generated text reflects the information in the source documents, helping identify potential hallucinations or misrepresentations.

Use this API to programmatically validate generated content against trusted source materials—an essential capability for applications in high-integrity environments such as legal, healthcare, scientific publishing, and enterprise knowledge systems.

The request body must include the following parameters:

  • model_parameters: Optionally specifies the evaluation model to use. Default is hhem_v2.2.
  • generated_text: The output text you want to evaluate, such as a model-generated summary, answer, or response.
  • source_texts: An array of source documents or passages used to verify the accuracy of the generated text.
  • language: The ISO 639-3 code representing the language of the provided texts (eng for English, fra for French).

Example request​

This example evaluates whether a generated statement about the Eiffel Tower is factually accurate based on two reference documents.

{
  "generated_text": "The Eiffel Tower is located in Berlin.",
  "source_texts": [
    "The Eiffel Tower is a famous landmark located in Paris, France.",
    "It was built in 1889 and remains one of the most visited monuments in the world."
  ],
  "language": "eng"
}

Example response​

The response includes a factual consistency score and probability estimates.

{
  "score": 0.23,
  "p_consistent": 0.12,
  "p_inconsistent": 0.88
}
  • score: A normalized value between 0.0 and 1.0 that reflects the overall factual alignment between the generated text and the source texts. Higher scores indicate stronger consistency.
  • p_consistent: The estimated probability that the generated text is factually consistent with the sources.
  • p_inconsistent: The estimated probability that the generated text contains factual inaccuracies relative to the source documents.

Request​

Responses​

The factual consistency evaluation results.

Last updated on by Paul Wozniczka