[Frontend] OpenAI Responses API supports Tool/Function calling

Signed-off-by: chaunceyjiang <chaunceyjiang@gmail.com>

Author: chaunceyjiang

vllm/entrypoints/openai/serving_chat.py

@@ -85,9 +85,6 @@ def __init__(
         self.tool_parser = self._get_tool_parser(
             tool_parser_name=tool_parser, enable_auto_tools=enable_auto_tools)
 
-        self.expand_tools_even_if_tool_choice_none = (
-            expand_tools_even_if_tool_choice_none)
-
         self.enable_prompt_tokens_details = enable_prompt_tokens_details
         self.enable_force_include_usage = enable_force_include_usage
         self.default_sampling_params = (

vllm/entrypoints/openai/serving_responses.py

@@ -73,8 +73,6 @@ def __init__(
             enable_force_include_usage=enable_force_include_usage,
         )
         self.enable_auto_tools = enable_auto_tools
-        self.expand_tools_even_if_tool_choice_none = (
-            expand_tools_even_if_tool_choice_none)
         self.chat_template = chat_template
         self.chat_template_content_format: Final = chat_template_content_format
 
@@ -145,20 +143,6 @@ async def create_responses(
             tokenizer = await self.engine_client.get_tokenizer(lora_request)
             if request.tools is None:
                 tool_dicts = None
-            elif (request.tool_choice == "none"
-                  and not self.expand_tools_even_if_tool_choice_none):
-                if len(request.tools) > 0:
-                    logger.warning_once(
-                        "Tools are specified but tool_choice is set to 'none' "
-                        "and --expand-tools-even-if-tool-choice-none is not "
-                        "enabled. Tool definitions will be excluded from the "
-                        "prompt. This behavior will change in vLLM v0.10 where "
-                        "tool definitions will be included by default even "
-                        "with tool_choice='none'. To adopt the new behavior "
-                        "now, use --expand-tools-even-if-tool-choice-none. "
-                        "To suppress this warning, either remove tools from "
-                        "the request or set tool_choice to a different value.")
-                tool_dicts = None
             else:
                 tool_dicts = [tool.model_dump() for tool in request.tools]
             _, request_prompts, engine_prompts = await self._preprocess_chat(
@@ -331,15 +315,13 @@ async def responses_full_generator(
             )
         outputs = []
         function_calls: list[FunctionCall] = []
-        if (not self.enable_auto_tools or not self.tool_parser):
+        if not self.enable_auto_tools or not self.tool_parser:
             # Tools are not enabled
             if reasoning_item:
                 outputs.append(reasoning_item)
             if message_item:
                 outputs.append(message_item)
-        elif (request.tool_choice == "none" and \
-            not self.expand_tools_even_if_tool_choice_none) or \
-                request.tool_choice is None:
+        elif request.tool_choice is None:
             # No tool calls.
             if reasoning_item:
                 outputs.append(reasoning_item)