diff --git a/backend/app/utils/toolkit/slack_toolkit.py b/backend/app/utils/toolkit/slack_toolkit.py
index 3c681ed89..920047a5f 100644
--- a/backend/app/utils/toolkit/slack_toolkit.py
+++ b/backend/app/utils/toolkit/slack_toolkit.py
@@ -64,19 +64,19 @@ class SlackToolkit(BaseSlackToolkit, AbstractToolkit):
     )
     def delete_slack_message(self, time_stamp: str, channel_id: str) -> str:
         return super().delete_slack_message(time_stamp, channel_id)
-    
+
     @listen_toolkit(
         BaseSlackToolkit.get_slack_user_list,
         lambda _: "get Slack user list",
     )
-    def get_slack_user_list(self) -> list[dict]:
+    def get_slack_user_list(self) -> str:
         return super().get_slack_user_list()
 
     @listen_toolkit(
         BaseSlackToolkit.get_slack_user_info,
         lambda _, user_id: f"get Slack user info with user id: {user_id}",
     )
-    def get_slack_user_info(self, user_id: str) -> dict:
+    def get_slack_user_info(self, user_id: str) -> str:
         return super().get_slack_user_info(user_id)
 
     @classmethod