# tinker_cookbook.exceptions.EvalGradingError

## _class_ [**tinker_cookbook.exceptions.EvalGradingError**](https://github.com/thinking-machines-lab/tinker-cookbook/blob/main/tinker_cookbook/exceptions.py#L255)( _[EvalError](https://tinker-docs.thinkingmachines.ai/cookbook/api-reference/exceptions/evalerror/)_)

The grading function failed on a model response.

Raised when the grader (programmatic, LLM judge, or execution-based)
cannot produce a score — e.g. the judge response is unparseable, the
sandbox crashes during test execution, or the answer extractor returns
an unexpected format.

The example is scored as a failure (reward=0). Check
`StoredTrajectory.error` for the specific grading failure.