diff --git a/vllm/entrypoints/openai/protocol.py b/vllm/entrypoints/openai/protocol.py
index 42fd430aad92f..d48057e0f123e 100644
--- a/vllm/entrypoints/openai/protocol.py
+++ b/vllm/entrypoints/openai/protocol.py
@@ -2,9 +2,9 @@
 # https://github.com/lm-sys/FastChat/blob/168ccc29d3f7edc50823016105c024fe2282732a/fastchat/protocol/openai_api_protocol.py
 import time
 from argparse import Namespace
-from typing import Any, Dict, List, Literal, Optional, Union
 from random import choices
 from string import ascii_letters, digits
+from typing import Any, Dict, List, Literal, Optional, Sequence, Union
 
 import torch
 from openai.types.chat import ChatCompletionContentPartParam
@@ -805,7 +805,7 @@ class ExtractedToolCallInformation(BaseModel):
     tools_called: bool
 
     # extracted tool calls
-    tool_calls: List[ToolCall | MistralToolCall]
+    tool_calls: Sequence[Union[ToolCall, MistralToolCall]]
 
     # content - per OpenAI spec, content AND tool calls can be returned rarely
     # But some models will do this intentionally
@@ -815,7 +815,8 @@ class ExtractedToolCallInformation(BaseModel):
 class ChatMessage(OpenAIBaseModel):
     role: str
     content: Optional[str] = None
-    tool_calls: List[ToolCall | MistralToolCall] = Field(default_factory=list)
+    tool_calls: Sequence[Union[ToolCall, MistralToolCall]] = Field(
+        default_factory=list)
 
 
 class ChatCompletionLogProb(OpenAIBaseModel):
diff --git a/vllm/entrypoints/openai/tool_parsers/mistral_tool_parser.py b/vllm/entrypoints/openai/tool_parsers/mistral_tool_parser.py
index df953c5d2d78f..4219324b2cab2 100644
--- a/vllm/entrypoints/openai/tool_parsers/mistral_tool_parser.py
+++ b/vllm/entrypoints/openai/tool_parsers/mistral_tool_parser.py
@@ -71,7 +71,7 @@ def extract_tool_calls(self,
             # load the JSON, and then use it to build the Function and
             # Tool Call
             function_call_arr = json.loads(raw_tool_call)
-            tool_calls: List[MistralToolCall] = [
+            tool_calls: Sequence[MistralToolCall] = [
                 MistralToolCall(
                     type="function",
                     function=FunctionCall(