diff --git a/backend/open_webui/utils/middleware.py b/backend/open_webui/utils/middleware.py
index c03e689ff2..eb4d1e742e 100644
--- a/backend/open_webui/utils/middleware.py
+++ b/backend/open_webui/utils/middleware.py
@@ -5008,7 +5008,8 @@ async def streaming_chat_response_handler(response, ctx):
                                                 if current_response_tool_call is None:
                                                     # Add the new tool call
                                                     delta_tool_call.setdefault('function', {})
-                                                    delta_tool_call['function'].setdefault('name', '')
+                                                    if delta_tool_call['function'].get('name') is None:
+                                                        delta_tool_call['function']['name'] = ''
                                                     delta_tool_call['id'] = delta_tool_call.get('id') or output_id('fc')
                                                     delta_arguments = delta_tool_call['function'].get('arguments')
                                                     if not isinstance(delta_arguments, str):