# AgenticRetrieveMemoryMetadataFilterLeft
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The left operand of a metadata filter expression. Set exactly one member.

## Contents
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**Important**  
This data type is a UNION, so only one of the following members can be specified when used or returned.

 ** metadataKey **   <a name="bedrock-Type-agent-runtime_AgenticRetrieveMemoryMetadataFilterLeft-metadataKey"></a>
The metadata key to filter on.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 128.  
Pattern: `[a-zA-Z0-9\s._:/=+@-]*`   
Required: No

## 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-agent-runtime-2023-07-26/AgenticRetrieveMemoryMetadataFilterLeft) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/bedrock-agent-runtime-2023-07-26/AgenticRetrieveMemoryMetadataFilterLeft) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/bedrock-agent-runtime-2023-07-26/AgenticRetrieveMemoryMetadataFilterLeft)