diff --git a/autogen/agentchat/contrib/retrieve_user_proxy_agent.py b/autogen/agentchat/contrib/retrieve_user_proxy_agent.py
index dd2ef0191270..261ab2062ef8 100644
--- a/autogen/agentchat/contrib/retrieve_user_proxy_agent.py
+++ b/autogen/agentchat/contrib/retrieve_user_proxy_agent.py
@@ -81,6 +81,7 @@
 """
 
 HASH_LENGTH = int(os.environ.get("HASH_LENGTH", 8))
+UPDATE_CONTEXT_IN_PROMPT = "you should reply exactly `UPDATE CONTEXT`"
 
 
 class RetrieveUserProxyAgent(UserProxyAgent):
@@ -471,7 +472,7 @@ def _check_update_context(self, message):
             message = message.get("content", "")
         elif not isinstance(message, str):
             message = ""
-        update_context_case1 = "UPDATE CONTEXT" in message[-20:].upper() or "UPDATE CONTEXT" in message[:20].upper()
+        update_context_case1 = "UPDATE CONTEXT" in message.upper() and UPDATE_CONTEXT_IN_PROMPT not in message
         update_context_case2 = self.customized_answer_prefix and self.customized_answer_prefix not in message.upper()
         return update_context_case1, update_context_case2