# Evaluator
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An evaluator to run against sessions.

## Contents
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 ** evaluatorId **   <a name="BedrockAgentCore-Type-Evaluator-evaluatorId"></a>
The unique identifier of the evaluator. Can reference built-in evaluators (e.g., `Builtin.Helpfulness`) or custom evaluators.  
Type: String  
Pattern: `(Builtin.[a-zA-Z0-9_-]+|[a-zA-Z][a-zA-Z0-9-_]{0,99}-[a-zA-Z0-9]{10})`   
Required: Yes

## See Also
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For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\+\+](https://docs.aws.amazon.com/goto/SdkForCpp/bedrock-agentcore-2024-02-28/Evaluator) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/bedrock-agentcore-2024-02-28/Evaluator) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/bedrock-agentcore-2024-02-28/Evaluator)