[Frontend] Support tool calling and reasoning parser

.buildkite/test-pipeline.yaml

@@ -118,7 +118,7 @@ steps:
   - pytest -v -s entrypoints/llm/test_generate.py # it needs a clean process
   - pytest -v -s entrypoints/llm/test_generate_multiple_loras.py # it needs a clean process
   - VLLM_USE_V1=0 pytest -v -s entrypoints/llm/test_guided_generate.py # it needs a clean process
-  - pytest -v -s entrypoints/openai --ignore=entrypoints/openai/test_oot_registration.py --ignore=entrypoints/openai/correctness/
+  - pytest -v -s entrypoints/openai --ignore=entrypoints/openai/test_oot_registration.py  --ignore=entrypoints/openai/test_chat_with_tool_reasoning.py --ignore=entrypoints/openai/correctness/
   - pytest -v -s entrypoints/test_chat_utils.py
   - VLLM_USE_V1=0 pytest -v -s entrypoints/offline_mode # Needs to avoid interference with other tests
 

docs/source/features/reasoning_outputs.md

@@ -10,10 +10,10 @@ Reasoning models return a additional `reasoning_content` field in their outputs,
 
 vLLM currently supports the following reasoning models:
 
-| Model Series | Parser Name | Structured Output Support |
-|--------------|-------------|------------------|
-| [DeepSeek R1 series](https://huggingface.co/collections/deepseek-ai/deepseek-r1-678e1e131c0169c0bc89728d) | `deepseek_r1` | `guided_json`, `guided_regex` |
-| [QwQ-32B](https://huggingface.co/Qwen/QwQ-32B) | `deepseek_r1` | `guided_json`, `guided_regex` |
+| Model Series | Parser Name | Structured Output Support | Tool Calling |
+|--------------|-------------|------------------|-------------|
+| [DeepSeek R1 series](https://huggingface.co/collections/deepseek-ai/deepseek-r1-678e1e131c0169c0bc89728d) | `deepseek_r1` | `guided_json`, `guided_regex` | ❌ |
+| [QwQ-32B](https://huggingface.co/Qwen/QwQ-32B) | `deepseek_r1` | `guided_json`, `guided_regex` | ✅ |
 
 ## Quickstart
 
@@ -170,10 +170,51 @@ print("reasoning_content: ", completion.choices[0].message.reasoning_content)
 print("content: ", completion.choices[0].message.content)
 ```
 
+## Tool Calling
+
+The reasoning content is also available when both tool calling and the reasoning parser are enabled. Additionally, tool calling only parses functions from the `content` field, not from the `reasoning_content`.
+
+```python
+from openai import OpenAI
+
+client = OpenAI(base_url="http://localhost:8000/v1", api_key="dummy")
+
+tools = [{
+    "type": "function",
+    "function": {
+        "name": "get_weather",
+        "description": "Get the current weather in a given location",
+        "parameters": {
+            "type": "object",
+            "properties": {
+                "location": {"type": "string", "description": "City and state, e.g., 'San Francisco, CA'"},
+                "unit": {"type": "string", "enum": ["celsius", "fahrenheit"]}
+            },
+            "required": ["location", "unit"]
+        }
+    }
+}]
+
+response = client.chat.completions.create(
+    model=client.models.list().data[0].id,
+    messages=[{"role": "user", "content": "What's the weather like in San Francisco?"}],
+    tools=tools,
+    tool_choice="auto"
+)
+
+print(response)
+tool_call = response.choices[0].message.tool_calls[0].function
+
+print(f"reasoning_content: {response.choices[0].message.reasoning_content}")
+print(f"Function called: {tool_call.name}")
+print(f"Arguments: {tool_call.arguments}")
+```
+
+For more examples, please refer to <gh-file:examples/online_serving/openai_chat_completion_tool_calls_with_reasoning.py> .
+
 ## Limitations
 
 - The reasoning content is only available for online serving's chat completion endpoint (`/v1/chat/completions`).
-- It is not compatible with [`tool_calling`](#tool_calling).
 
 ## How to support a new reasoning model
 

examples/online_serving/openai_chat_completion_tool_calls_with_reasoning.py

@@ -0,0 +1,177 @@
+# SPDX-License-Identifier: Apache-2.0
+"""
+An example demonstrates how to use tool calling with reasoning models 
+like QwQ-32B. The reasoning_content will not be parsed by the tool 
+calling process; only the final output will be parsed.
+
+To run this example, you need to start the vLLM server with both 
+the reasoning parser and tool calling enabled.
+
+```bash
+vllm serve Qwen/QwQ-32B \
+     --enable-reasoning --reasoning-parser deepseek_r1 \
+     --enable-auto-tool-choice --tool-call-parser hermes
+
+```
+
+"""
+
+from openai import OpenAI
+
+
+# Now, simulate a tool call
+def get_current_weather(city: str, state: str, unit: 'str'):
+    return ("The weather in Dallas, Texas is 85 degrees fahrenheit. It is "
+            "partly cloudly, with highs in the 90's.")
+
+
+available_tools = {"get_current_weather": get_current_weather}
+
+# Modify OpenAI's API key and API base to use vLLM's API server.
+openai_api_key = "EMPTY"
+openai_api_base = "http://localhost:8000/v1"
+
+client = OpenAI(
+    api_key=openai_api_key,
+    base_url=openai_api_base,
+)
+
+models = client.models.list()
+model = models.data[0].id
+
+tools = [{
+    "type": "function",
+    "function": {
+        "name": "get_current_weather",
+        "description": "Get the current weather in a given location",
+        "parameters": {
+            "type": "object",
+            "properties": {
+                "city": {
+                    "type":
+                    "string",
+                    "description":
+                    "The city to find the weather for, e.g. 'San Francisco'"
+                },
+                "state": {
+                    "type":
+                    "string",
+                    "description":
+                    "the two-letter abbreviation for the state that the city is"
+                    " in, e.g. 'CA' which would mean 'California'"
+                },
+                "unit": {
+                    "type": "string",
+                    "description": "The unit to fetch the temperature in",
+                    "enum": ["celsius", "fahrenheit"]
+                }
+            },
+            "required": ["city", "state", "unit"]
+        }
+    }
+}]
+messages = [{
+    "role": "user",
+    "content": "Hi! How are you doing today?"
+}, {
+    "role": "assistant",
+    "content": "I'm doing well! How can I help you?"
+}, {
+    "role":
+    "user",
+    "content":
+    "Can you tell me what the temperate will be in Dallas, in fahrenheit?"
+}]
+
+
+def extract_reasoning_and_calls(chunks: list):
+    reasoning_content = ""
+    tool_call_idx = -1
+    arguments = []
+    function_names = []
+    for chunk in chunks:
+        if chunk.choices[0].delta.tool_calls:
+            tool_call = chunk.choices[0].delta.tool_calls[0]
+            if tool_call.index != tool_call_idx:
+                tool_call_idx = chunk.choices[0].delta.tool_calls[0].index
+                arguments.append("")
+                function_names.append("")
+
+            if tool_call.function:
+                if tool_call.function.name:
+                    function_names[tool_call_idx] = tool_call.function.name
+
+                if tool_call.function.arguments:
+                    arguments[tool_call_idx] += tool_call.function.arguments
+        else:
+            if hasattr(chunk.choices[0].delta, "reasoning_content"):
+                reasoning_content += chunk.choices[0].delta.reasoning_content
+    return reasoning_content, arguments, function_names
+
+
+print("---------Full Generate With Automatic Function Calling-------------")
+tool_calls = client.chat.completions.create(messages=messages,
+                                            model=model,
+                                            tools=tools)
+print(f"reasoning_content: {tool_calls.choices[0].message.reasoning_content}")
+print(f"function name: "
+      f"{tool_calls.choices[0].message.tool_calls[0].function.name}")
+print(f"function arguments: "
+      f"{tool_calls.choices[0].message.tool_calls[0].function.arguments}")
+
+print("----------Stream Generate With Automatic Function Calling-----------")
+tool_calls_stream = client.chat.completions.create(messages=messages,
+                                                   model=model,
+                                                   tools=tools,
+                                                   stream=True)
+chunks = []
+for chunk in tool_calls_stream:
+    chunks.append(chunk)
+
+reasoning_content, arguments, function_names = extract_reasoning_and_calls(
+    chunks)
+
+print(f"reasoning_content: {reasoning_content}")
+print(f"function name: {function_names[0]}")
+print(f"function arguments: {arguments[0]}")
+
+print("----------Full Generate With Named Function Calling-----------------")
+tool_calls = client.chat.completions.create(messages=messages,
+                                            model=model,
+                                            tools=tools,
+                                            tool_choice={
+                                                "type": "function",
+                                                "function": {
+                                                    "name":
+                                                    "get_current_weather"
+                                                }
+                                            })
+
+tool_call = tool_calls.choices[0].message.tool_calls[0].function
+print(f"reasoning_content: {tool_calls.choices[0].message.reasoning_content}")
+print(f"function name: {tool_call.name}")
+print(f"function arguments: {tool_call.arguments}")
+print("----------Stream Generate With Named Function Calling--------------")
+
+tool_calls_stream = client.chat.completions.create(
+    messages=messages,
+    model=model,
+    tools=tools,
+    tool_choice={
+        "type": "function",
+        "function": {
+            "name": "get_current_weather"
+        }
+    },
+    stream=True)
+
+chunks = []
+for chunk in tool_calls_stream:
+    chunks.append(chunk)
+
+reasoning_content, arguments, function_names = extract_reasoning_and_calls(
+    chunks)
+print(f"reasoning_content: {reasoning_content}")
+print(f"function name: {function_names[0]}")
+print(f"function arguments: {arguments[0]}")
+print("\n\n")