Python: Filter conversation_id when passing kwargs to agent as tool (#3266)

* Filter conversation_id when passing kwargs to agent as tool

* Small fix

* Update python/samples/getting_started/agents/azure_ai/README.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update python/samples/getting_started/agents/openai/openai_responses_client_with_agent_as_tool.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update python/samples/getting_started/agents/azure_ai/azure_ai_with_agent_as_tool.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

python/packages/core/agent_framework/_agents.py

@@ -470,8 +470,8 @@ class BaseAgent(SerializationMixin):
             # Extract the input from kwargs using the specified arg_name
             input_text = kwargs.get(arg_name, "")
 
-            # Forward all kwargs except the arg_name to support runtime context propagation
-            forwarded_kwargs = {k: v for k, v in kwargs.items() if k != arg_name}
+            # Forward runtime context kwargs, excluding arg_name and conversation_id.
+            forwarded_kwargs = {k: v for k, v in kwargs.items() if k not in (arg_name, "conversation_id")}
 
             if stream_callback is None:
                 # Use non-streaming mode

python/packages/core/tests/core/test_as_tool_kwargs_propagation.py

@@ -313,3 +313,44 @@ class TestAsToolKwargsPropagation:
         # Verify second call had its own kwargs (not leaked from first)
         assert second_call_kwargs.get("session_id") == "session-2"
         assert second_call_kwargs.get("api_token") == "token-2"
+
+    async def test_as_tool_excludes_conversation_id_from_forwarded_kwargs(self, chat_client: MockChatClient) -> None:
+        """Test that conversation_id is not forwarded to sub-agent."""
+        captured_kwargs: dict[str, Any] = {}
+
+        @agent_middleware
+        async def capture_middleware(
+            context: AgentRunContext, next: Callable[[AgentRunContext], Awaitable[None]]
+        ) -> None:
+            captured_kwargs.update(context.kwargs)
+            await next(context)
+
+        # Setup mock response
+        chat_client.responses = [
+            ChatResponse(messages=[ChatMessage(role="assistant", text="Response from sub-agent")]),
+        ]
+
+        sub_agent = ChatAgent(
+            chat_client=chat_client,
+            name="sub_agent",
+            middleware=[capture_middleware],
+        )
+
+        tool = sub_agent.as_tool(name="delegate", arg_name="task")
+
+        # Invoke tool with conversation_id in kwargs (simulating parent's conversation state)
+        await tool.invoke(
+            arguments=tool.input_model(task="Test delegation"),
+            conversation_id="conv-parent-456",
+            api_token="secret-xyz-123",
+            user_id="user-456",
+        )
+
+        # Verify conversation_id was NOT forwarded to sub-agent
+        assert "conversation_id" not in captured_kwargs, (
+            f"conversation_id should not be forwarded, but got: {captured_kwargs}"
+        )
+
+        # Verify other kwargs were still forwarded
+        assert captured_kwargs.get("api_token") == "secret-xyz-123"
+        assert captured_kwargs.get("user_id") == "user-456"