[gpt-oss] Add loop for built-in tool call (#22374)

Signed-off-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>
Co-authored-by: LiuXiaoxuanPKU <lilyliupku@gmail.com>
Co-authored-by: simon-mo <xmo@berkeley.edu>
Co-authored-by: Chen Zhang <zhangch99@outlook.com>
Co-authored-by: Hongxia Yang <62075498+hongxiayang@users.noreply.github.com>
Co-authored-by: Minseok Lee <47620120+minseokl@users.noreply.github.com>
Co-authored-by: Yongye Zhu <zyy1102000@gmail.com>

vllm/entrypoints/openai/serving_engine.py

@@ -35,6 +35,7 @@ from vllm.entrypoints.chat_utils import (ChatCompletionMessageParam,
                                          apply_mistral_chat_template,
                                          parse_chat_messages_futures,
                                          resolve_chat_template_content_format)
+from vllm.entrypoints.context import ConversationContext
 from vllm.entrypoints.logger import RequestLogger
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               ChatCompletionResponse,
@@ -948,6 +949,61 @@ class OpenAIServing:
 
         return conversation, [request_prompt], [engine_prompt]
 
+    async def _generate_with_builtin_tools(
+        self,
+        request_id: str,
+        request_prompt: RequestPrompt,
+        engine_prompt: EngineTokensPrompt,
+        sampling_params: SamplingParams,
+        context: ConversationContext,
+        lora_request: Optional[LoRARequest] = None,
+        priority: int = 0,
+        **kwargs,
+    ):
+        orig_priority = priority
+        while True:
+            self._log_inputs(
+                request_id,
+                request_prompt,
+                params=sampling_params,
+                lora_request=lora_request,
+            )
+            generator = self.engine_client.generate(
+                engine_prompt,
+                sampling_params,
+                request_id,
+                lora_request=lora_request,
+                priority=priority,
+                **kwargs,
+            )
+            async for res in generator:
+                context.append_output(res)
+                # NOTE(woosuk): The stop condition is handled by the engine.
+                yield context
+
+            if not context.need_builtin_tool_call():
+                # The model did not ask for a tool call, so we're done.
+                break
+
+            # Call the tool and update the context with the result.
+            tool_output = await context.call_tool()
+            context.append_output(tool_output)
+
+            # TODO: uncomment this and enable tool output streaming
+            # yield context
+
+            # Create inputs for the next turn.
+            # Render the next prompt token ids.
+            prompt_token_ids = context.render_for_completion()
+            engine_prompt = EngineTokensPrompt(
+                prompt_token_ids=prompt_token_ids)
+            request_prompt = prompt_token_ids
+            # Update the sampling params.
+            sampling_params.max_tokens = (self.max_model_len -
+                                          len(prompt_token_ids))
+            # OPTIMIZATION
+            priority = orig_priority - 1
+
     def _load_prompt_embeds(
         self,
         prompt_embeds: Optional[Union[bytes, list[bytes]]],

vllm/entrypoints/openai/serving_responses.py

@@ -16,6 +16,7 @@ from vllm.config import ModelConfig
 from vllm.engine.protocol import EngineClient
 from vllm.entrypoints.chat_utils import (ChatCompletionMessageParam,
                                          ChatTemplateContentFormatOption)
+from vllm.entrypoints.context import ConversationContext, SimpleContext
 from vllm.entrypoints.logger import RequestLogger
 # yapf conflicts with isort for this block
 # yapf: disable
@@ -29,7 +30,6 @@ from vllm.entrypoints.openai.protocol import (ErrorResponse,
 from vllm.entrypoints.openai.serving_engine import OpenAIServing
 from vllm.entrypoints.openai.serving_models import OpenAIServingModels
 from vllm.logger import init_logger
-from vllm.outputs import RequestOutput
 from vllm.reasoning import ReasoningParser, ReasoningParserManager
 from vllm.sampling_params import SamplingParams
 from vllm.transformers_utils.tokenizer import AnyTokenizer
@@ -187,7 +187,7 @@ class OpenAIServingResponses(OpenAIServing):
             raw_request.state.request_metadata = request_metadata
 
         # Schedule the request and get the result generator.
-        generators: list[AsyncGenerator[RequestOutput, None]] = []
+        generators: list[AsyncGenerator[ConversationContext, None]] = []
         try:
             for i, engine_prompt in enumerate(engine_prompts):
                 default_max_tokens = self.max_model_len - len(
@@ -195,21 +195,19 @@ class OpenAIServingResponses(OpenAIServing):
                 sampling_params = request.to_sampling_params(
                     default_max_tokens, self.default_sampling_params)
 
-                self._log_inputs(request.request_id,
-                                 request_prompts[i],
-                                 params=sampling_params,
-                                 lora_request=lora_request)
-
                 trace_headers = (None if raw_request is None else await
                                  self._get_trace_headers(raw_request.headers))
 
-                generator = self.engine_client.generate(
+                context = SimpleContext()
-                    engine_prompt,
+                generator = self._generate_with_builtin_tools(
-                    sampling_params,
+                    request_id=request.request_id,
-                    request.request_id,
+                    request_prompt=request_prompts[i],
+                    engine_prompt=engine_prompt,
+                    sampling_params=sampling_params,
+                    context=context,
                     lora_request=lora_request,
-                    trace_headers=trace_headers,
                     priority=request.priority,
+                    trace_headers=trace_headers,
                 )
                 generators.append(generator)
         except ValueError as e:
@@ -277,7 +275,7 @@ class OpenAIServingResponses(OpenAIServing):
         self,
         request: ResponsesRequest,
         sampling_params: SamplingParams,
-        result_generator: AsyncIterator[RequestOutput],
+        result_generator: AsyncIterator[ConversationContext],
         model_name: str,
         tokenizer: AnyTokenizer,
         request_metadata: RequestResponseMetadata,
@@ -285,17 +283,20 @@ class OpenAIServingResponses(OpenAIServing):
     ) -> Union[ErrorResponse, ResponsesResponse]:
         if created_time is None:
             created_time = int(time.time())
-        final_res: Optional[RequestOutput] = None
 
+        context: Optional[ConversationContext] = None
         try:
-            async for res in result_generator:
+            async for context in result_generator:
-                final_res = res
+                pass
         except asyncio.CancelledError:
             return self.create_error_response("Client disconnected")
         except ValueError as e:
             # TODO: Use a vllm-specific Validation Error
             return self.create_error_response(str(e))
 
+        assert context is not None
+        assert isinstance(context, SimpleContext)
+        final_res = context.last_output
         assert final_res is not None
         assert len(final_res.outputs) == 1
         final_output = final_res.outputs[0]