diff --git a/tests/client-sdk/agents/test_agents.py b/tests/client-sdk/agents/test_agents.py
index eb6e68e8f..7b7bce813 100644
--- a/tests/client-sdk/agents/test_agents.py
+++ b/tests/client-sdk/agents/test_agents.py
@@ -45,7 +45,7 @@ class TestClientTool(ClientTool):
             tool_name=tool_call.tool_name,
             content=response_str,
         )
-        return [message]
+        return message
 
     def get_name(self) -> str:
         return "get_boiling_point"