Python: Fix streaming path to emit mcp_server_tool_result on output_item.done instead of output_item.added (microsoft#4821)

* Fix streaming path to deliver mcp_server_tool_result content (microsoft#4814)

Remove premature mcp_server_tool_result emission from the
response.output_item.added/mcp_call handler — at that point the MCP
server has not yet responded and output is always None.

Add a handler for response.mcp_call.completed that emits
mcp_server_tool_result with the actual tool output, matching the
non-streaming path behavior.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix streaming path to deliver mcp_server_tool_result content (microsoft#4814)

Stop eagerly emitting mcp_server_tool_result on response.output_item.added
(when output is always None). Instead, handle response.output_item.done for
mcp_call items, which carries the full McpCall with populated output.

This matches the non-streaming path which guards with 'if item.output is not
None' before emitting the result.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix test docstring to match actual implementation event name

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address review: call_id fallback and raw_representation consistency (microsoft#4814)

- Add call_id fallback in response.output_item.done mcp_call handler to
  match the output_item.added handler pattern
- Use done_item instead of event for raw_representation to keep
  consistent with other output_item branches and non-streaming path
- Add test for call_id fallback when id attribute is missing
- Add raw_representation assertions to existing done handler tests

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address review: call_id fallback for non-streaming path and test coverage (microsoft#4814)

- Apply defensive call_id fallback (getattr with id/call_id/empty) to
  non-streaming mcp_call path for consistency with streaming path
- Add raw_representation assertion to call_id fallback test
- Add test for empty-string fallback when neither id nor call_id exist

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <copilot@github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: 3 people

python/packages/openai/agent_framework_openai/_chat_client.py

@@ -1728,7 +1728,7 @@ def _parse_response_from_openai(
                         )
                     )
                 case "mcp_call":
-                    call_id = item.id
+                    call_id = getattr(item, "id", None) or getattr(item, "call_id", None) or ""
                     contents.append(
                         Content.from_mcp_server_tool_call(
                             call_id=call_id,
@@ -2118,27 +2118,7 @@ def _parse_chunk_from_openai(
                                 raw_representation=event_item,
                             )
                         )
-                        result_output = (
-                            getattr(event_item, "result", None)
-                            or getattr(event_item, "output", None)
-                            or getattr(event_item, "outputs", None)
-                        )
-                        parsed_output: list[Content] | None = None
-                        if result_output:
-                            normalized = (  # pyright: ignore[reportUnknownVariableType]
-                                result_output
-                                if isinstance(result_output, Sequence)
-                                and not isinstance(result_output, (str, bytes, MutableMapping))
-                                else [result_output]
-                            )
-                            parsed_output = [Content.from_dict(output_item) for output_item in normalized]  # pyright: ignore[reportArgumentType,reportUnknownVariableType]
-                        contents.append(
-                            Content.from_mcp_server_tool_result(
-                                call_id=call_id,
-                                output=parsed_output,
-                                raw_representation=event_item,
-                            )
-                        )
+                        # Result deferred to response.output_item.done
                     case "code_interpreter_call":  # ResponseOutputCodeInterpreterCall
                         call_id = getattr(event_item, "call_id", None) or getattr(event_item, "id", None)
                         outputs: list[Content] = []
@@ -2408,6 +2388,21 @@ def _get_ann_value(key: str) -> Any:
                         )
                 else:
                     logger.debug("Unparsed annotation type in streaming: %s", ann_type)
+            case "response.output_item.done":
+                done_item = event.item
+                if getattr(done_item, "type", None) == "mcp_call":
+                    call_id = getattr(done_item, "id", None) or getattr(done_item, "call_id", None) or ""
+                    output_text = getattr(done_item, "output", None)
+                    parsed_output: list[Content] | None = (
+                        [Content.from_text(text=output_text)] if isinstance(output_text, str) else None
+                    )
+                    contents.append(
+                        Content.from_mcp_server_tool_result(
+                            call_id=call_id,
+                            output=parsed_output,
+                            raw_representation=done_item,
+                        )
+                    )
             case _:
                 logger.debug("Unparsed event of type: %s: %s", event.type, event)
 

python/packages/openai/tests/openai/test_openai_chat_client.py

@@ -1184,11 +1184,13 @@ def test_parse_response_from_openai_with_mcp_server_tool_result() -> None:
     assert result_content.output is not None
 
 
-def test_parse_chunk_from_openai_with_mcp_call_result() -> None:
-    """Test _parse_chunk_from_openai with MCP call output."""
+def test_parse_chunk_from_openai_with_mcp_call_added_defers_result() -> None:
+    """Test that response.output_item.added for mcp_call emits only the call, not the result.
+
+    The result is deferred to response.output_item.done.
+    """
     client = OpenAIChatClient(model="test-model", api_key="test-key")
 
-    # Mock event with MCP call that has output
     mock_event = MagicMock()
     mock_event.type = "response.output_item.added"
 
@@ -1199,8 +1201,9 @@ def test_parse_chunk_from_openai_with_mcp_call_result() -> None:
     mock_item.name = "fetch_resource"
     mock_item.server_label = "ResourceServer"
     mock_item.arguments = {"resource_id": "123"}
-    # Use proper content structure that _parse_content can handle
-    mock_item.result = [{"type": "text", "text": "test result"}]
+    mock_item.result = None
+    mock_item.output = None
+    mock_item.outputs = None
 
     mock_event.item = mock_item
     mock_event.output_index = 0
@@ -1209,18 +1212,124 @@ def test_parse_chunk_from_openai_with_mcp_call_result() -> None:
 
     update = client._parse_chunk_from_openai(mock_event, options={}, function_call_ids=function_call_ids)
 
-    # Should have both call and result in contents
-    assert len(update.contents) == 2
-    call_content, result_content = update.contents
+    # Should have only the call content — result is deferred
+    assert len(update.contents) == 1
+    call_content = update.contents[0]
 
     assert call_content.type == "mcp_server_tool_call"
     assert call_content.call_id in ["mcp_call_456", "call_456"]
     assert call_content.tool_name == "fetch_resource"
 
+    # No result should be emitted at this point
+    result_contents = [c for c in update.contents if c.type == "mcp_server_tool_result"]
+    assert len(result_contents) == 0
+
+
+def test_parse_chunk_from_openai_with_mcp_output_item_done() -> None:
+    """Test that response.output_item.done for mcp_call emits mcp_server_tool_result with output."""
+    client = OpenAIChatClient(model="test-model", api_key="test-key")
+
+    mock_event = MagicMock()
+    mock_event.type = "response.output_item.done"
+
+    mock_item = MagicMock()
+    mock_item.type = "mcp_call"
+    mock_item.id = "mcp_call_456"
+    mock_item.output = "The weather in Seattle is 72F and sunny."
+    mock_event.item = mock_item
+
+    function_call_ids: dict[int, tuple[str, str]] = {}
+
+    update = client._parse_chunk_from_openai(mock_event, options={}, function_call_ids=function_call_ids)
+
+    assert len(update.contents) == 1
+    result_content = update.contents[0]
+
+    assert result_content.type == "mcp_server_tool_result"
+    assert result_content.call_id == "mcp_call_456"
+    assert result_content.output is not None
+    assert len(result_content.output) == 1
+    assert result_content.output[0].text == "The weather in Seattle is 72F and sunny."
+    assert result_content.raw_representation is mock_item
+
+
+def test_parse_chunk_from_openai_with_mcp_output_item_done_no_output() -> None:
+    """Test that response.output_item.done for mcp_call with no output emits result with None output."""
+    client = OpenAIChatClient(model="test-model", api_key="test-key")
+
+    mock_event = MagicMock()
+    mock_event.type = "response.output_item.done"
+
+    mock_item = MagicMock()
+    mock_item.type = "mcp_call"
+    mock_item.id = "mcp_call_789"
+    mock_item.output = None
+    mock_event.item = mock_item
+
+    function_call_ids: dict[int, tuple[str, str]] = {}
+
+    update = client._parse_chunk_from_openai(mock_event, options={}, function_call_ids=function_call_ids)
+
+    assert len(update.contents) == 1
+    result_content = update.contents[0]
+
+    assert result_content.type == "mcp_server_tool_result"
+    assert result_content.call_id == "mcp_call_789"
+    assert result_content.output is None
+    assert result_content.raw_representation is mock_item
+
+
+def test_parse_chunk_from_openai_with_mcp_output_item_done_call_id_fallback() -> None:
+    """Test that response.output_item.done for mcp_call falls back to call_id when id is missing."""
+    client = OpenAIChatClient(model="test-model", api_key="test-key")
+
+    mock_event = MagicMock()
+    mock_event.type = "response.output_item.done"
+
+    mock_item = MagicMock(spec=[])
+    mock_item.type = "mcp_call"
+    mock_item.call_id = "mcp_fallback_123"
+    mock_item.output = "fallback result"
+    mock_event.item = mock_item
+
+    function_call_ids: dict[int, tuple[str, str]] = {}
+
+    update = client._parse_chunk_from_openai(mock_event, options={}, function_call_ids=function_call_ids)
+
+    assert len(update.contents) == 1
+    result_content = update.contents[0]
+
+    assert result_content.type == "mcp_server_tool_result"
+    assert result_content.call_id == "mcp_fallback_123"
+    assert result_content.output is not None
+    assert result_content.output[0].text == "fallback result"
+    assert result_content.raw_representation is mock_item
+
+
+def test_parse_chunk_from_openai_with_mcp_output_item_done_no_id_fallback() -> None:
+    """Test that response.output_item.done for mcp_call falls back to empty string when neither id nor call_id exist."""
+    client = OpenAIChatClient(model="test-model", api_key="test-key")
+
+    mock_event = MagicMock()
+    mock_event.type = "response.output_item.done"
+
+    mock_item = MagicMock(spec=[])
+    mock_item.type = "mcp_call"
+    mock_item.output = "some result"
+    mock_event.item = mock_item
+
+    function_call_ids: dict[int, tuple[str, str]] = {}
+
+    update = client._parse_chunk_from_openai(mock_event, options={}, function_call_ids=function_call_ids)
+
+    assert len(update.contents) == 1
+    result_content = update.contents[0]
+
     assert result_content.type == "mcp_server_tool_result"
-    assert result_content.call_id in ["mcp_call_456", "call_456"]
-    # Verify the output was parsed
+    assert result_content.call_id == ""
     assert result_content.output is not None
+    assert result_content.output[0].text == "some result"
+    assert result_content.raw_representation is mock_item
 
 
 def test_prepare_message_for_openai_with_function_approval_response() -> None: