# Descriptors
<a name="API_Descriptors"></a>

 The protocol-specific descriptors that describe how to connect to and use the registry record.

## Contents
<a name="API_Descriptors_Contents"></a>

 ** a2aAgentCard **   <a name="agentregistry-Type-Descriptors-a2aAgentCard"></a>
 The A2A agent card descriptor, populated when the record type is AGENT.  
Type: [A2aAgentCardDescriptor](API_A2aAgentCardDescriptor.md) object  
Required: No

 ** agentSkillsDefinition **   <a name="agentregistry-Type-Descriptors-agentSkillsDefinition"></a>
 The agent skills definition descriptor, populated when the record type is SKILL.  
Type: [AgentSkillsDefinitionDescriptor](API_AgentSkillsDefinitionDescriptor.md) object  
Required: No

 ** custom **   <a name="agentregistry-Type-Descriptors-custom"></a>
 The custom descriptor, populated when the record type is CUSTOM.  
Type: [CustomDescriptor](API_CustomDescriptor.md) object  
Required: No

 ** mcpServer **   <a name="agentregistry-Type-Descriptors-mcpServer"></a>
 The MCP server descriptor, populated when the record type is MCP.  
Type: [McpServerDescriptor](API_McpServerDescriptor.md) object  
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/vestry-data-plane-2025-12-01/Descriptors) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/vestry-data-plane-2025-12-01/Descriptors) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/vestry-data-plane-2025-12-01/Descriptors)