[Fix] correct tool_id for kimi-k2 when use tool_choice=required (#21259)

Co-authored-by: wangzhengtao <wangzhengtao@msh.team>

tests/entrypoints/openai/test_completion_with_function_calling.py

@@ -13,48 +13,7 @@ from ...utils import RemoteOpenAIServer
 # any model with a chat template should work here
 MODEL_NAME = "Qwen/Qwen3-0.6B"
 
-
+tools = [
-@pytest.fixture(scope="module")
-def server():  # noqa: F811
-    args = [
-        # use half precision for speed and memory savings in CI environment
-        "--dtype",
-        "half",
-        "--enable-auto-tool-choice",
-        "--guided-decoding-backend",
-        "xgrammar",
-        "--tool-call-parser",
-        "hermes",
-        "--reasoning-parser",
-        "qwen3",
-    ]
-
-    with RemoteOpenAIServer(MODEL_NAME, args) as remote_server:
-        yield remote_server
-
-
-@pytest_asyncio.fixture
-async def client(server):
-    async with server.get_async_client() as async_client:
-        yield async_client
-
-
-@pytest.mark.asyncio
-@pytest.mark.parametrize("model_name", [MODEL_NAME])
-@pytest.mark.parametrize("stream", [True, False])
-@pytest.mark.parametrize("tool_choice", [
-    "auto", "required", {
-        "type": "function",
-        "function": {
-            "name": "get_current_weather"
-        }
-    }
-])
-@pytest.mark.parametrize("enable_thinking", [True, False])
-async def test_function_tool_use(client: openai.AsyncOpenAI, model_name: str,
-                                 stream: bool, tool_choice: Union[str, dict],
-                                 enable_thinking: bool):
-    tools = [
     {
         "type": "function",
         "function": {
@@ -77,14 +36,12 @@ async def test_function_tool_use(client: openai.AsyncOpenAI, model_name: str,
                     },
                     "unit": {
                         "type": "string",
-                            "description":
+                        "description": "The unit to fetch the temperature in",
-                            "The unit to fetch the temperature in",
                         "enum": ["celsius", "fahrenheit"],
                     },
                     "options": {
                         "$ref": "#/$defs/WeatherOptions",
-                            "description":
+                        "description": "Optional parameters for weather query",
-                            "Optional parameters for weather query",
                     },
                 },
                 "required": ["country", "unit"],
@@ -149,8 +106,7 @@ async def test_function_tool_use(client: openai.AsyncOpenAI, model_name: str,
                     },
                     "unit": {
                         "type": "string",
-                            "description":
+                        "description": "The unit to fetch the temperature in",
-                            "The unit to fetch the temperature in",
                         "enum": ["celsius", "fahrenheit"],
                     },
                 },
@@ -158,9 +114,9 @@ async def test_function_tool_use(client: openai.AsyncOpenAI, model_name: str,
             },
         },
     },
-    ]
+]
 
-    messages = [
+messages = [
     {
         "role": "user",
         "content": "Hi! How are you doing today?"
@@ -176,7 +132,51 @@ async def test_function_tool_use(client: openai.AsyncOpenAI, model_name: str,
         "Can you tell me what the current weather is in Berlin and the "\
         "forecast for the next 5 days, in fahrenheit?",
     },
+]
+
+
+@pytest.fixture(scope="module")
+def server():  # noqa: F811
+    args = [
+        # use half precision for speed and memory savings in CI environment
+        "--dtype",
+        "half",
+        "--enable-auto-tool-choice",
+        "--guided-decoding-backend",
+        "xgrammar",
+        "--tool-call-parser",
+        "hermes",
+        "--reasoning-parser",
+        "qwen3",
+        "--gpu-memory-utilization",
+        "0.4"
     ]
+
+    with RemoteOpenAIServer(MODEL_NAME, args) as remote_server:
+        yield remote_server
+
+
+@pytest_asyncio.fixture
+async def client(server):
+    async with server.get_async_client() as async_client:
+        yield async_client
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("model_name", [MODEL_NAME])
+@pytest.mark.parametrize("stream", [True, False])
+@pytest.mark.parametrize("tool_choice", [
+    "auto", "required", {
+        "type": "function",
+        "function": {
+            "name": "get_current_weather"
+        }
+    }
+])
+@pytest.mark.parametrize("enable_thinking", [True, False])
+async def test_function_tool_use(client: openai.AsyncOpenAI, model_name: str,
+                                 stream: bool, tool_choice: Union[str, dict],
+                                 enable_thinking: bool):
     if not stream:
         # Non-streaming test
         chat_completion = await client.chat.completions.create(
@@ -216,3 +216,71 @@ async def test_function_tool_use(client: openai.AsyncOpenAI, model_name: str,
                 output.extend(chunk.choices[0].delta.tool_calls)
 
         assert len(output) > 0
+
+
+@pytest.fixture(scope="module")
+def k2_server():  # noqa: F811
+    args = [
+        # use half precision for speed and memory savings in CI environment
+        "--dtype",
+        "half",
+        "--enable-auto-tool-choice",
+        "--guided-decoding-backend",
+        "xgrammar",
+        "--tool-call-parser",
+        "hermes",
+        "--reasoning-parser",
+        "qwen3",
+        "--gpu-memory-utilization",
+        "0.4",
+    ]
+    # hack to test kimi_k2 tool use tool_id format.
+    # avoid error in is_deepseek_mla check by setting kv_lora_rank=null
+    with RemoteOpenAIServer(MODEL_NAME,
+                            args,
+                            override_hf_configs={
+                                "model_type": 'kimi_k2',
+                                'kv_lora_rank': None
+                            }) as remote_server:
+        yield remote_server
+
+
+@pytest_asyncio.fixture
+async def k2_client(k2_server):
+    async with k2_server.get_async_client() as async_client:
+        yield async_client
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("model_name", [MODEL_NAME])
+@pytest.mark.parametrize("stream", [True, False])
+@pytest.mark.parametrize("tool_choice", ["required"])
+async def test_tool_id_kimi_k2(k2_client: openai.AsyncOpenAI, model_name: str,
+                               stream: bool, tool_choice: str):
+
+    if not stream:
+        # Non-streaming test
+        chat_completion = await k2_client.chat.completions.create(
+            messages=messages,
+            model=model_name,
+            tools=tools,
+            tool_choice=tool_choice)
+        assert chat_completion.choices[0].message.tool_calls is not None
+        assert len(chat_completion.choices[0].message.tool_calls) > 0
+        assert chat_completion.choices[0].message.tool_calls[
+            0].id == 'functions.get_current_weather:0'
+    else:
+        # Streaming test
+        output_stream = await k2_client.chat.completions.create(
+            messages=messages,
+            model=model_name,
+            tools=tools,
+            tool_choice=tool_choice,
+            stream=True)
+
+        output = []
+        async for chunk in output_stream:
+            if chunk.choices and chunk.choices[0].delta.tool_calls:
+                output.extend(chunk.choices[0].delta.tool_calls)
+        for o in output:
+            assert o.id is None or o.id == 'functions.get_current_weather:0'

tests/utils.py

@@ -5,6 +5,7 @@ import asyncio
 import copy
 import functools
 import importlib
+import json
 import os
 import signal
 import subprocess
@@ -101,7 +102,8 @@ class RemoteOpenAIServer:
                  env_dict: Optional[dict[str, str]] = None,
                  seed: Optional[int] = 0,
                  auto_port: bool = True,
-                 max_wait_seconds: Optional[float] = None) -> None:
+                 max_wait_seconds: Optional[float] = None,
+                 override_hf_configs: Optional[dict[str, Any]] = None) -> None:
         if auto_port:
             if "-p" in vllm_serve_args or "--port" in vllm_serve_args:
                 raise ValueError("You have manually specified the port "
@@ -120,6 +122,12 @@ class RemoteOpenAIServer:
 
             vllm_serve_args = vllm_serve_args + ["--seed", str(seed)]
 
+        if override_hf_configs is not None:
+            vllm_serve_args = vllm_serve_args + [
+                "--hf-overrides",
+                json.dumps(override_hf_configs)
+            ]
+
         parser = FlexibleArgumentParser(
             description="vLLM's remote OpenAI server.")
         subparsers = parser.add_subparsers(required=False, dest="subparser")

vllm/entrypoints/chat_utils.py

@@ -1345,5 +1345,18 @@ def apply_mistral_chat_template(
             "template")
         raise ValueError(str(e)) from e
 
-def random_tool_call_id() -> str:
+def get_history_tool_calls_cnt(conversation: list[ConversationMessage]):
+    idx = 0
+    for msg in conversation:
+        if msg['role'] == 'assistant':
+            tool_calls = msg.get('tool_calls')
+            idx += len(list(tool_calls)) if tool_calls is not None else 0 # noqa
+    return idx
+
+def make_tool_call_id(id_type:str='random', func_name=None, idx=None):
+
+    if id_type=='kimi_k2':
+        return f'functions.{func_name}:{idx}'
+    else:
+        # by default return random
         return f"chatcmpl-tool-{random_uuid()}"

vllm/entrypoints/openai/protocol.py

@@ -38,7 +38,7 @@ from typing_extensions import TypeAlias
 
 from vllm import envs
 from vllm.entrypoints.chat_utils import (ChatCompletionMessageParam,
-                                         random_tool_call_id)
+                                         make_tool_call_id)
 from vllm.entrypoints.score_utils import (ScoreContentPartParam,
                                           ScoreMultiModalParam)
 from vllm.logger import init_logger
@@ -1634,7 +1634,7 @@ class FunctionCall(OpenAIBaseModel):
 
 
 class ToolCall(OpenAIBaseModel):
-    id: str = Field(default_factory=random_tool_call_id)
+    id: str = Field(default_factory=make_tool_call_id)
     type: Literal["function"] = "function"
     function: FunctionCall
 

vllm/entrypoints/openai/serving_chat.py

@@ -19,7 +19,8 @@ from vllm.config import ModelConfig
 from vllm.engine.protocol import EngineClient
 from vllm.entrypoints.chat_utils import (ChatTemplateContentFormatOption,
                                          ConversationMessage,
-                                         random_tool_call_id)
+                                         get_history_tool_calls_cnt,
+                                         make_tool_call_id)
 from vllm.entrypoints.harmony_utils import (
     get_developer_message, get_stop_tokens_for_assistant_actions,
     get_streamable_parser_for_assistant, get_system_message, parse_chat_input,
@@ -133,6 +134,10 @@ class OpenAIServingChat(OpenAIServing):
             source = "model" if source == "auto" else source
             logger.info("Using default chat sampling params from %s: %s",
                         source, self.default_sampling_params)
+        if self.model_config.hf_config.model_type == 'kimi_k2':
+            self.tool_call_id_type = 'kimi_k2'
+        else:
+            self.tool_call_id_type = 'random'
 
         self.use_harmony = model_config.hf_config.model_type == "gpt_oss"
         if self.use_harmony:
@@ -379,6 +384,7 @@ class OpenAIServingChat(OpenAIServing):
         current_text: Optional[str],
         delta_text: str,
         function_name_returned: bool,
+        tool_call_idx: Optional[int] = None
     ) -> tuple[Optional[DeltaMessage], bool]:
         if current_text is None or current_text == "":
             # if the current text is empty, we cannot parse it
@@ -424,8 +430,12 @@ class OpenAIServingChat(OpenAIServing):
                         current_tool_call = obj[-2]
 
                     function_name_returned = True
+                    tool_call_id = make_tool_call_id(
+                        id_type=self.tool_call_id_type,
+                        func_name=current_tool_call["name"],
+                        idx=tool_call_idx)
                     delta_message = DeltaMessage(tool_calls=[
-                        DeltaToolCall(id=random_tool_call_id(),
+                        DeltaToolCall(id=tool_call_id,
                                       function=DeltaFunctionCall(
                                           name=current_tool_call["name"],
                                           arguments=arguments),
@@ -491,6 +501,10 @@ class OpenAIServingChat(OpenAIServing):
 
         all_previous_token_ids: Optional[list[list[int]]]
         function_name_returned = [False] * num_choices
+        if self.tool_call_id_type == 'kimi_k2':
+            history_tool_call_cnt = get_history_tool_calls_cnt(conversation)
+        else:
+            history_tool_call_cnt = 0
 
         # Always track previous_texts for comprehensive output logging
         previous_texts = [""] * num_choices
@@ -673,7 +687,6 @@ class OpenAIServingChat(OpenAIServing):
                         previous_text = previous_texts[i]
                         previous_token_ids = all_previous_token_ids[i]
                         current_text = previous_text + delta_text
-
                         # avoid the None + list error.
                         if previous_token_ids:
                             current_token_ids = previous_token_ids + as_list(
@@ -733,7 +746,7 @@ class OpenAIServingChat(OpenAIServing):
                                     index=i)
                             else:
                                 delta_tool_call = DeltaToolCall(
-                                    id=random_tool_call_id(),
+                                    id=make_tool_call_id(),
                                     type="function",
                                     function=DeltaFunctionCall(
                                         name=tool_choice_function_name,
@@ -764,7 +777,11 @@ class OpenAIServingChat(OpenAIServing):
                                 previous_text=previous_text,
                                 current_text=content,
                                 delta_text=delta_text,
-                                function_name_returned=fn_name_returned))
+                                function_name_returned=fn_name_returned,
+                                tool_call_idx=history_tool_call_cnt))
+                        if (delta_message and delta_message.tool_calls and
+                                delta_message.tool_calls[0].id is not None):
+                            history_tool_call_cnt += 1
 
                         # update the previous values for the next iteration
                         previous_texts[i] = current_text
@@ -1089,6 +1106,10 @@ class OpenAIServingChat(OpenAIServing):
         assert final_res is not None
 
         choices: list[ChatCompletionResponseChoice] = []
+        if self.tool_call_id_type == 'kimi_k2':
+            history_tool_call_cnt = get_history_tool_calls_cnt(conversation)
+        else:
+            history_tool_call_cnt = 0
 
         role = self.get_chat_request_role(request)
         for output in final_res.outputs:
@@ -1194,17 +1215,26 @@ class OpenAIServingChat(OpenAIServing):
                 assert content is not None
                 tool_calls = TypeAdapter(
                     list[FunctionDefinition]).validate_json(content)
+                tool_call_ids = []
+                for tool_call in tool_calls:
+                    tool_call_ids.append(
+                        make_tool_call_id(id_type=self.tool_call_id_type,
+                                          func_name=tool_call.name,
+                                          idx=history_tool_call_cnt))
+                    history_tool_call_cnt += 1
                 message = ChatMessage(
                     role=role,
                     content="",
-                    reasoning_content=reasoning_content,
                     tool_calls=[
-                        tool_call_class(function=FunctionCall(
+                        tool_call_class(id=tool_call_ids[i],
+                                        function=FunctionCall(
                                             name=tool_call.name,
-                            arguments=json.dumps(tool_call.parameters,
+                                            arguments=json.dumps(
+                                                tool_call.parameters,
                                                 ensure_ascii=False)))
-                        for tool_call in tool_calls
+                        for i, tool_call in enumerate(tool_calls)
-                    ])
+                    ],
+                    reasoning_content=reasoning_content)
 
             # if the request doesn't use tool choice
             # OR specifies to not use a tool
@@ -1248,7 +1278,6 @@ class OpenAIServingChat(OpenAIServing):
                     if (tool_call_info.content
                             and len(tool_call_info.content) > 0):
                         ret_content = tool_call_info.content
-
                     message = ChatMessage(role=role,
                                           reasoning_content=reasoning_content,
                                           content=ret_content)
@@ -1327,12 +1356,11 @@ class OpenAIServingChat(OpenAIServing):
                 elif choice.message.tool_calls:
                     # For tool calls, log the function name and arguments
                     tool_call_descriptions = []
-                    for tool_call in choice.message.tool_calls:
+                    for tc in choice.message.tool_calls:
-                        if hasattr(tool_call.function, "name") and hasattr(
+                        if hasattr(tc.function, "name") and hasattr(
-                                tool_call.function, "arguments"):
+                                tc.function, "arguments"):
                             tool_call_descriptions.append(
-                                f"{tool_call.function.name}({tool_call.function.arguments})"
+                                f"{tc.function.name}({tc.function.arguments})")
-                            )
                     tool_calls_str = ", ".join(tool_call_descriptions)
                     output_text = f"[tool_calls: {tool_calls_str}]"
 

vllm/entrypoints/openai/tool_parsers/deepseekv3_tool_parser.py

@@ -6,7 +6,7 @@ from typing import Union
 
 import regex as re
 
-from vllm.entrypoints.chat_utils import random_tool_call_id
+from vllm.entrypoints.chat_utils import make_tool_call_id
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               DeltaFunctionCall, DeltaMessage,
                                               DeltaToolCall,
@@ -267,7 +267,7 @@ class DeepSeekV3ToolParser(ToolParser):
                         DeltaToolCall(
                             index=self.current_tool_id,
                             type="function",
-                            id=random_tool_call_id(),
+                            id=make_tool_call_id(),
                             function=DeltaFunctionCall(
                                 name=function_name).model_dump(
                                     exclude_none=True),

vllm/entrypoints/openai/tool_parsers/granite_20b_fc_tool_parser.py

@@ -10,7 +10,7 @@ import partial_json_parser
 import regex as re
 from partial_json_parser.core.options import Allow
 
-from vllm.entrypoints.chat_utils import random_tool_call_id
+from vllm.entrypoints.chat_utils import make_tool_call_id
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               DeltaFunctionCall, DeltaMessage,
                                               DeltaToolCall,
@@ -203,7 +203,7 @@ class Granite20bFCToolParser(ToolParser):
                     delta = DeltaMessage(tool_calls=[
                         DeltaToolCall(index=self.current_tool_id,
                                       type="function",
-                                      id=random_tool_call_id(),
+                                      id=make_tool_call_id(),
                                       function=DeltaFunctionCall(
                                           name=function_name).model_dump(
                                               exclude_none=True))

vllm/entrypoints/openai/tool_parsers/granite_tool_parser.py

@@ -8,7 +8,7 @@ from typing import Union
 import partial_json_parser
 from partial_json_parser.core.options import Allow
 
-from vllm.entrypoints.chat_utils import random_tool_call_id
+from vllm.entrypoints.chat_utils import make_tool_call_id
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               DeltaFunctionCall, DeltaMessage,
                                               DeltaToolCall,
@@ -185,7 +185,7 @@ class GraniteToolParser(ToolParser):
                     delta = DeltaMessage(tool_calls=[
                         DeltaToolCall(index=self.current_tool_id,
                                       type="function",
-                                      id=random_tool_call_id(),
+                                      id=make_tool_call_id(),
                                       function=DeltaFunctionCall(
                                           name=function_name).model_dump(
                                               exclude_none=True))

vllm/entrypoints/openai/tool_parsers/hermes_tool_parser.py

@@ -9,7 +9,7 @@ import partial_json_parser
 import regex as re
 from partial_json_parser.core.options import Allow
 
-from vllm.entrypoints.chat_utils import random_tool_call_id
+from vllm.entrypoints.chat_utils import make_tool_call_id
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               DeltaFunctionCall, DeltaMessage,
                                               DeltaToolCall,
@@ -307,7 +307,7 @@ class Hermes2ProToolParser(ToolParser):
                     return DeltaMessage(tool_calls=[
                         DeltaToolCall(index=self.current_tool_id,
                                       type="function",
-                                      id=random_tool_call_id(),
+                                      id=make_tool_call_id(),
                                       function=DeltaFunctionCall(
                                           name=function_name).model_dump(
                                               exclude_none=True))

vllm/entrypoints/openai/tool_parsers/internlm2_tool_parser.py

@@ -8,7 +8,7 @@ from typing import Union
 import partial_json_parser
 from partial_json_parser.core.options import Allow
 
-from vllm.entrypoints.chat_utils import random_tool_call_id
+from vllm.entrypoints.chat_utils import make_tool_call_id
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               DeltaFunctionCall, DeltaMessage,
                                               DeltaToolCall,
@@ -107,7 +107,7 @@ class Internlm2ToolParser(ToolParser):
                     delta = DeltaMessage(tool_calls=[
                         DeltaToolCall(index=self.current_tool_id,
                                       type="function",
-                                      id=random_tool_call_id(),
+                                      id=make_tool_call_id(),
                                       function=DeltaFunctionCall(
                                           name=function_name).model_dump(
                                               exclude_none=True))

vllm/entrypoints/openai/tool_parsers/jamba_tool_parser.py

@@ -9,7 +9,7 @@ import partial_json_parser
 import regex as re
 from partial_json_parser.core.options import Allow
 
-from vllm.entrypoints.chat_utils import random_tool_call_id
+from vllm.entrypoints.chat_utils import make_tool_call_id
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               DeltaFunctionCall, DeltaMessage,
                                               DeltaToolCall,
@@ -222,7 +222,7 @@ class JambaToolParser(ToolParser):
                     delta = DeltaMessage(tool_calls=[
                         DeltaToolCall(index=self.current_tool_id,
                                       type="function",
-                                      id=random_tool_call_id(),
+                                      id=make_tool_call_id(),
                                       function=DeltaFunctionCall(
                                           name=function_name).model_dump(
                                               exclude_none=True))

vllm/entrypoints/openai/tool_parsers/llama_tool_parser.py

@@ -10,7 +10,7 @@ import regex as re
 from partial_json_parser.core.options import Allow
 from transformers import PreTrainedTokenizerBase
 
-from vllm.entrypoints.chat_utils import random_tool_call_id
+from vllm.entrypoints.chat_utils import make_tool_call_id
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               DeltaFunctionCall, DeltaMessage,
                                               DeltaToolCall,
@@ -213,7 +213,7 @@ class Llama3JsonToolParser(ToolParser):
                     delta = DeltaMessage(tool_calls=[
                         DeltaToolCall(index=self.current_tool_id,
                                       type="function",
-                                      id=random_tool_call_id(),
+                                      id=make_tool_call_id(),
                                       function=DeltaFunctionCall(
                                           name=function_name).model_dump(
                                               exclude_none=True))

vllm/entrypoints/openai/tool_parsers/minimax_tool_parser.py

@@ -7,7 +7,7 @@ from typing import Any, Optional, Union
 
 import regex as re
 
-from vllm.entrypoints.chat_utils import random_tool_call_id
+from vllm.entrypoints.chat_utils import make_tool_call_id
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               DeltaFunctionCall, DeltaMessage,
                                               DeltaToolCall,
@@ -394,7 +394,7 @@ class MinimaxToolParser(ToolParser):
             sent_tools.append({
                 "sent_name": False,
                 "sent_arguments": "",
-                "id": random_tool_call_id(),
+                "id": make_tool_call_id(),
             })
 
         while len(tool_ids) < tool_count:

vllm/entrypoints/openai/tool_parsers/phi4mini_tool_parser.py

@@ -8,7 +8,7 @@ from typing import Any, Optional
 import regex as re
 from transformers import PreTrainedTokenizerBase
 
-from vllm.entrypoints.chat_utils import random_tool_call_id
+from vllm.entrypoints.chat_utils import make_tool_call_id
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               DeltaMessage,
                                               ExtractedToolCallInformation,
@@ -74,7 +74,7 @@ class Phi4MiniJsonToolParser(ToolParser):
 
             tool_calls: list[ToolCall] = [
                 ToolCall(
-                    id=random_tool_call_id(),
+                    id=make_tool_call_id(),
                     type="function",
                     function=FunctionCall(
                         name=raw_function_call["name"],

vllm/entrypoints/openai/tool_parsers/xlam_tool_parser.py

@@ -7,7 +7,7 @@ from typing import Any, Optional, Union
 
 import regex as re
 
-from vllm.entrypoints.chat_utils import random_tool_call_id
+from vllm.entrypoints.chat_utils import make_tool_call_id
 from vllm.entrypoints.openai.protocol import (ChatCompletionRequest,
                                               DeltaFunctionCall, DeltaMessage,
                                               DeltaToolCall,
@@ -226,7 +226,7 @@ class xLAMToolParser(ToolParser):
                         function_name = name_match.group(1)
 
                         # The test expects us to send just the name first
-                        tool_id = random_tool_call_id()
+                        tool_id = make_tool_call_id()
                         delta = DeltaMessage(tool_calls=[
                             DeltaToolCall(
                                 index=0,