diff --git a/fastdeploy/entrypoints/openai/serving_chat.py b/fastdeploy/entrypoints/openai/serving_chat.py
index 2af6eb138..440f0571e 100644
--- a/fastdeploy/entrypoints/openai/serving_chat.py
+++ b/fastdeploy/entrypoints/openai/serving_chat.py
@@ -323,7 +323,9 @@ class OpenAIServingChat:
                             continue
                         delta_message.content = delta_message_output.content or ""
                         delta_message.reasoning_content = delta_message_output.reasoning_content or ""
-                        delta_message.tool_calls = delta_message_output.tool_calls
+                        if delta_message_output.tool_calls:
+                            delta_message.tool_calls = delta_message_output.tool_calls
+                            tool_called = True
 
                     choice = ChatCompletionResponseStreamChoice(
                         index=0,
diff --git a/fastdeploy/entrypoints/openai/serving_completion.py b/fastdeploy/entrypoints/openai/serving_completion.py
index 9dbf06b8b..7eb322535 100644
--- a/fastdeploy/entrypoints/openai/serving_completion.py
+++ b/fastdeploy/entrypoints/openai/serving_completion.py
@@ -418,7 +418,9 @@ class OpenAIServingCompletion:
                             continue
                         delta_message.text = delta_message_output.content or ""
                         delta_message.reasoning_content = delta_message_output.reasoning_content or ""
-                        delta_message.tool_calls = delta_message_output.tool_calls
+                        if delta_message_output.tool_calls:
+                            delta_message.tool_calls = delta_message_output.tool_calls
+                            tool_called[idx] = True
 
                     choices.append(delta_message)