diff --git a/knowledge_storm/rm.py b/knowledge_storm/rm.py
index c177b8f4..9ae5955b 100644
--- a/knowledge_storm/rm.py
+++ b/knowledge_storm/rm.py
@@ -334,6 +334,7 @@ def forward(self, query_or_queries: Union[str, List[str]], exclude_urls: List[st
 
 
 class StanfordOvalArxivRM(dspy.Retrieve):
+    """[Alpha] This retrieval class is for internal use only, not intended for the public."""
     def __init__(self, endpoint, k=3):
         super().__init__(k=k)
         self.endpoint = endpoint