AssistantAgent.metadata for user/application identity information associated with the agent. #6048 (#6057)

This PR introduces a metadata field in AssistantAgentConfig, allowing
applications to assign and track identity information for agents.
The metadata field is a Dict[str, str] and is included in the
configuration for proper serialization.


---------

Co-authored-by: Eric Zhu <ekzhu@users.noreply.github.com>

python/packages/autogen-agentchat/src/autogen_agentchat/agents/_assistant_agent.py

@@ -73,6 +73,7 @@ class AssistantAgentConfig(BaseModel):
     model_client_stream: bool = False
     reflect_on_tool_use: bool
     tool_call_summary_format: str
+    metadata: Dict[str, str] | None = None
 
 
 class AssistantAgent(BaseChatAgent, Component[AssistantAgentConfig]):
@@ -169,6 +170,7 @@ class AssistantAgent(BaseChatAgent, Component[AssistantAgentConfig]):
             Available variables: `{tool_name}`, `{arguments}`, `{result}`.
             For example, `"{tool_name}: {result}"` will create a summary like `"tool_name: result"`.
         memory (Sequence[Memory] | None, optional): The memory store to use for the agent. Defaults to `None`.
+        metadata (Dict[str, str] | None, optional): Optional metadata for tracking.
 
     Raises:
         ValueError: If tool names are not unique.
@@ -613,8 +615,10 @@ class AssistantAgent(BaseChatAgent, Component[AssistantAgentConfig]):
         reflect_on_tool_use: bool = False,
         tool_call_summary_format: str = "{result}",
         memory: Sequence[Memory] | None = None,
+        metadata: Dict[str, str] | None = None,
     ):
         super().__init__(name=name, description=description)
+        self._metadata = metadata or {}
         if reflect_on_tool_use and ModelFamily.is_claude(model_client.model_info["family"]):
             warnings.warn(
                 "Claude models may not work with reflection on tool use because Claude requires that any requests including a previous tool use or tool result must include the original tools definition."
@@ -1214,6 +1218,7 @@ class AssistantAgent(BaseChatAgent, Component[AssistantAgentConfig]):
             model_client_stream=self._model_client_stream,
             reflect_on_tool_use=self._reflect_on_tool_use,
             tool_call_summary_format=self._tool_call_summary_format,
+            metadata=self._metadata,
         )
 
     @classmethod
@@ -1231,4 +1236,5 @@ class AssistantAgent(BaseChatAgent, Component[AssistantAgentConfig]):
             model_client_stream=config.model_client_stream,
             reflect_on_tool_use=config.reflect_on_tool_use,
             tool_call_summary_format=config.tool_call_summary_format,
+            metadata=config.metadata,
         )