[responsesAPI][8] input/output messages for ResponsesParser (#30158)

Signed-off-by: Andrew Xia <axia@fb.com>
Signed-off-by: Andrew Xia <axia@meta.com>
Co-authored-by: Andrew Xia <axia@fb.com>
Co-authored-by: Chauncey <chaunceyjiang@gmail.com>

tests/entrypoints/openai/test_response_api_parsable_context.py

@@ -165,6 +165,7 @@ async def test_mcp_tool_call(client: OpenAI, model_name: str):
         model=model_name,
         input="What is 13 * 24? Use python to calculate the result.",
         tools=[{"type": "code_interpreter", "container": {"type": "auto"}}],
+        extra_body={"enable_response_messages": True},
         temperature=0.0,
     )
 
@@ -178,3 +179,8 @@ async def test_mcp_tool_call(client: OpenAI, model_name: str):
     # make sure the correct math is in the final output
     assert response.output[3].type == "message"
     assert "312" in response.output[3].content[0].text
+
+    # test raw input_messages / output_messages
+    assert len(response.input_messages) == 1
+    assert len(response.output_messages) == 3
+    assert "312" in response.output_messages[2]["message"]

vllm/entrypoints/context.py

@@ -297,12 +297,40 @@ class ParsableContext(ConversationContext):
         self.chat_template = chat_template
         self.chat_template_content_format = chat_template_content_format
 
+        self.input_messages: list[ResponseRawMessageAndToken] = []
+        self.output_messages: list[ResponseRawMessageAndToken] = []
+
     def append_output(self, output: RequestOutput) -> None:
         self.num_prompt_tokens = len(output.prompt_token_ids or [])
         self.num_cached_tokens = output.num_cached_tokens or 0
         self.num_output_tokens += len(output.outputs[0].token_ids or [])
         self.parser.process(output.outputs[0])
 
+        # only store if enable_response_messages is True, save memory
+        if self.request.enable_response_messages:
+            output_prompt = output.prompt or ""
+            output_prompt_token_ids = output.prompt_token_ids or []
+            if len(self.input_messages) == 0:
+                self.input_messages.append(
+                    ResponseRawMessageAndToken(
+                        message=output_prompt,
+                        tokens=output_prompt_token_ids,
+                    )
+                )
+            else:
+                self.output_messages.append(
+                    ResponseRawMessageAndToken(
+                        message=output_prompt,
+                        tokens=output_prompt_token_ids,
+                    )
+                )
+            self.output_messages.append(
+                ResponseRawMessageAndToken(
+                    message=output.outputs[0].text,
+                    tokens=output.outputs[0].token_ids,
+                )
+            )
+
     def append_tool_output(self, output: list[ResponseInputOutputItem]) -> None:
         self.parser.response_messages.extend(output)
 

vllm/entrypoints/openai/parser/responses_parser.py

@@ -3,7 +3,11 @@
 import logging
 from collections.abc import Callable
 
-from openai.types.responses.response_function_tool_call import ResponseFunctionToolCall
+from openai.types.responses import ResponseFunctionToolCall, ResponseOutputItem
+from openai.types.responses.response_function_tool_call_output_item import (
+    ResponseFunctionToolCallOutputItem,
+)
+from openai.types.responses.response_output_item import McpCall
 from openai.types.responses.response_output_message import ResponseOutputMessage
 from openai.types.responses.response_output_text import ResponseOutputText
 from openai.types.responses.response_reasoning_item import (
@@ -11,6 +15,7 @@ from openai.types.responses.response_reasoning_item import (
     ResponseReasoningItem,
 )
 
+from vllm.entrypoints.constants import MCP_PREFIX
 from vllm.entrypoints.openai.protocol import ResponseInputOutputItem, ResponsesRequest
 from vllm.outputs import CompletionOutput
 from vllm.reasoning.abs_reasoning_parsers import ReasoningParser
@@ -111,6 +116,37 @@ class ResponsesParser:
 
         return self
 
+    def make_response_output_items_from_parsable_context(
+        self,
+    ) -> list[ResponseOutputItem]:
+        """Given a list of sentences, construct ResponseOutput Items."""
+        response_messages = self.response_messages[self.num_init_messages :]
+        output_messages: list[ResponseOutputItem] = []
+        for message in response_messages:
+            if not isinstance(message, ResponseFunctionToolCallOutputItem):
+                output_messages.append(message)
+            else:
+                if len(output_messages) == 0:
+                    raise ValueError(
+                        "Cannot have a FunctionToolCallOutput before FunctionToolCall."
+                    )
+                if isinstance(output_messages[-1], ResponseFunctionToolCall):
+                    mcp_message = McpCall(
+                        id=f"{MCP_PREFIX}{random_uuid()}",
+                        arguments=output_messages[-1].arguments,
+                        name=output_messages[-1].name,
+                        server_label=output_messages[
+                            -1
+                        ].name,  # TODO: store the server label
+                        type="mcp_call",
+                        status="completed",
+                        output=message.output,
+                        # TODO: support error output
+                    )
+                    output_messages[-1] = mcp_message
+
+        return output_messages
+
 
 def get_responses_parser_for_simple_context(
     *,

vllm/entrypoints/openai/serving_responses.py

@@ -104,7 +104,6 @@ from vllm.entrypoints.responses_utils import (
     construct_input_messages,
     construct_tool_dicts,
     extract_tool_types,
-    make_response_output_items_from_parsable_context,
 )
 from vllm.entrypoints.tool_server import ToolServer
 from vllm.inputs.data import TokensPrompt
@@ -658,17 +657,11 @@ class OpenAIServingResponses(OpenAIServing):
             else:
                 status = "incomplete"
         elif isinstance(context, ParsableContext):
-            response_messages = context.parser.response_messages[
-                context.parser.num_init_messages :
-            ]
-            output = make_response_output_items_from_parsable_context(response_messages)
+            output = context.parser.make_response_output_items_from_parsable_context()
 
-            # TODO: context for non-gptoss models doesn't use messages
-            # so we can't get them out yet
             if request.enable_response_messages:
-                raise NotImplementedError(
-                    "enable_response_messages is currently only supported for gpt-oss"
-                )
+                input_messages = context.input_messages
+                output_messages = context.output_messages
 
             # TODO: Calculate usage.
             # assert final_res.prompt_token_ids is not None

vllm/entrypoints/responses_utils.py

@@ -16,7 +16,6 @@ from openai.types.responses.response import ToolChoice
 from openai.types.responses.response_function_tool_call_output_item import (
     ResponseFunctionToolCallOutputItem,
 )
-from openai.types.responses.response_output_item import McpCall
 from openai.types.responses.response_output_message import ResponseOutputMessage
 from openai.types.responses.response_reasoning_item import ResponseReasoningItem
 from openai.types.responses.tool import Tool
@@ -27,38 +26,6 @@ from vllm.entrypoints.openai.protocol import (
     ChatCompletionMessageParam,
     ResponseInputOutputItem,
 )
-from vllm.utils import random_uuid
-
-
-def make_response_output_items_from_parsable_context(
-    response_messages: list[ResponseInputOutputItem],
-) -> list[ResponseOutputItem]:
-    """Given a list of sentences, construct ResponseOutput Items."""
-    output_messages: list[ResponseOutputItem] = []
-    for message in response_messages:
-        if not isinstance(message, ResponseFunctionToolCallOutputItem):
-            output_messages.append(message)
-        else:
-            if len(output_messages) == 0:
-                raise ValueError(
-                    "Cannot have a FunctionToolCallOutput before FunctionToolCall."
-                )
-            if isinstance(output_messages[-1], ResponseFunctionToolCall):
-                mcp_message = McpCall(
-                    id=f"{MCP_PREFIX}{random_uuid()}",
-                    arguments=output_messages[-1].arguments,
-                    name=output_messages[-1].name,
-                    server_label=output_messages[
-                        -1
-                    ].name,  # TODO: store the server label
-                    type=f"{MCP_PREFIX}call",
-                    status="completed",
-                    output=message.output,
-                    # TODO: support error output
-                )
-                output_messages[-1] = mcp_message
-
-    return output_messages
 
 
 def construct_input_messages(