diff --git a/src/memos/api/handlers/suggestion_handler.py b/src/memos/api/handlers/suggestion_handler.py
index a10251ec2..99e5885fb 100644
--- a/src/memos/api/handlers/suggestion_handler.py
+++ b/src/memos/api/handlers/suggestion_handler.py
@@ -32,22 +32,18 @@ def _get_further_suggestion(
 
     Args:
         llm: LLM instance for generating suggestions
-        message: Recent chat messages (can be a list of message dicts or a plain string)
+        message: Recent chat messages (MessageList or string for backward compatibility)
 
     Returns:
         List of suggestion queries
     """
     try:
+        # Handle backward compatibility: convert string to MessageList format
         if isinstance(message, str):
-            dialogue_info = message
-        else:
-            dialogue_info = "\n".join(
-                [
-                    f"{msg['role']}: {msg['content']}"
-                    for msg in message[-2:]
-                    if isinstance(msg, dict)
-                ]
-            )
+            logger.warning("Received string message, converting to MessageList format")
+            message = [{"role": "user", "content": message}]
+        
+        dialogue_info = "\n".join([f"{msg['role']}: {msg['content']}" for msg in message[-2:]])
         further_suggestion_prompt = FURTHER_SUGGESTION_PROMPT.format(dialogue=dialogue_info)
         message_list = [{"role": "system", "content": further_suggestion_prompt}]
         response = llm.generate(message_list)