Fix send_chat_history to send request with empty chat history (#143)

* Initial plan

* Fix send_chat_history to send request even with empty chat_history_messages

- Removed early return for empty chat_history_messages that was short-circuiting HTTP request
- Updated docstring to document that empty lists are allowed and will still send request
- Updated unit test to verify HTTP requests are made with empty chat history
- Moved json import to top of test file

Co-authored-by: pontemonti <7850950+pontemonti@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: pontemonti <7850950+pontemonti@users.noreply.github.com>

Author: Copilot

libraries/microsoft-agents-a365-tooling/microsoft_agents_a365/tooling/services/mcp_tool_server_configuration_service.py

@@ -569,7 +569,8 @@ async def send_chat_history(
                           Must have a valid activity with conversation.id, activity.id, and
                           activity.text.
             chat_history_messages: List of ChatHistoryMessage objects representing the chat
-                                   history. Must be non-empty.
+                                   history. May be empty - an empty list will still send a
+                                   request to the MCP platform with empty chat history.
             options: Optional ToolOptions instance containing optional parameters.
 
         Returns:
@@ -578,7 +579,7 @@ async def send_chat_history(
                              On failure, returns OperationResult.failed() with error details.
 
         Raises:
-            ValueError: If turn_context is None, chat_history_messages is None or empty,
+            ValueError: If turn_context is None, chat_history_messages is None,
                         turn_context.activity is None, or any of the required fields
                         (conversation.id, activity.id, activity.text) are missing or empty.
 
@@ -602,10 +603,8 @@ async def send_chat_history(
         if chat_history_messages is None:
             raise ValueError("chat_history_messages cannot be None")
 
-        # Handle empty messages - return success with warning (consistent with extension behavior)
-        if len(chat_history_messages) == 0:
-            self._logger.warning("Empty message list provided to send_chat_history")
-            return OperationResult.success()
+        # Note: Empty chat_history_messages is allowed - we still send the request to MCP platform
+        # The platform needs to receive the request even with empty chat history
 
         # Extract required information from turn context
         if not turn_context.activity:

tests/tooling/services/test_send_chat_history.py

@@ -3,6 +3,7 @@
 
 """Unit tests for send_chat_history method in McpToolServerConfigurationService."""
 
+import json
 from datetime import UTC, datetime
 from unittest.mock import AsyncMock, MagicMock, Mock, patch
 
@@ -146,14 +147,37 @@ async def test_send_chat_history_validates_chat_history_messages(
             await service.send_chat_history(mock_turn_context, None)
 
     @pytest.mark.asyncio
-    async def test_send_chat_history_empty_list_returns_success(self, service, mock_turn_context):
-        """Test that send_chat_history returns success for empty list (CRM-008)."""
-        # Act
-        result = await service.send_chat_history(mock_turn_context, [])
-
-        # Assert - empty list should return success, not raise exception
-        assert result.succeeded is True
-        assert len(result.errors) == 0
+    async def test_send_chat_history_empty_list_sends_request(self, service, mock_turn_context):
+        """Test that send_chat_history sends request to MCP platform even with empty list."""
+        # Arrange
+        mock_response = AsyncMock()
+        mock_response.status = 200
+        mock_response.text = AsyncMock(return_value="OK")
+
+        # Mock aiohttp.ClientSession
+        with patch("aiohttp.ClientSession") as mock_session:
+            mock_session_instance = MagicMock()
+            mock_post = AsyncMock()
+            mock_post.__aenter__.return_value = mock_response
+            mock_session_instance.post.return_value = mock_post
+            mock_session.return_value.__aenter__.return_value = mock_session_instance
+
+            # Act
+            result = await service.send_chat_history(mock_turn_context, [])
+
+            # Assert - empty list should still make HTTP request and return success
+            assert result.succeeded is True
+            assert len(result.errors) == 0
+
+            # Verify HTTP request was actually made
+            assert mock_session_instance.post.called
+            call_args = mock_session_instance.post.call_args
+            assert "real-time-threat-protection/chat-message" in call_args[0][0]
+
+            # Verify the payload contains an empty chat history
+            data = call_args[1]["data"]
+            payload = json.loads(data)
+            assert payload["chatHistory"] == []
 
     @pytest.mark.asyncio
     async def test_send_chat_history_validates_activity(self, service, chat_history_messages):