diff --git a/api/core/workflow/nodes/tool/tool_node.py b/api/core/workflow/nodes/tool/tool_node.py
index 140fe71f60..86d36f474d 100644
--- a/api/core/workflow/nodes/tool/tool_node.py
+++ b/api/core/workflow/nodes/tool/tool_node.py
@@ -316,7 +316,8 @@ class ToolNode(BaseNode):
                     variables[variable_name] = variable_value
             elif message.type == ToolInvokeMessage.MessageType.FILE:
                 assert message.meta is not None
-                assert isinstance(message.meta, File)
+                assert isinstance(message.meta, dict)
+                assert "file" in message.meta and isinstance(message.meta["file"], File)
                 files.append(message.meta["file"])
             elif message.type == ToolInvokeMessage.MessageType.LOG:
                 assert isinstance(message.message, ToolInvokeMessage.LogMessage)