Update app.py

app.py

@@ -14,7 +14,7 @@ class AttachmentDownloadTool(Tool):
     description = "Downloads the file associated with the given task_id. If it does not exist, return None. input: task_id。output: attachment files bytes or None"
     inputs = {
         "task_id": {
-            "type": "str",
+            "type": "string",
             "description": "task_id that needs to download attachment files."
         }
     }