pref support multi-modal messages

Author: yuan.wang

src/memos/memories/textual/prefer_text_memory/spliter.py

@@ -87,7 +87,7 @@ def _split_with_overlap(self, data: MessageList) -> list[MessageList]:
                 # overlap 1 turns (Q + A = 2)
                 context = copy.deepcopy(chunk[-2:]) if i + 1 < len(data) else []
                 chunk = context
-        if chunk and len(chunk) % 2 == 0:
+        if chunk:
             chunks.append(chunk)
 
         return chunks

src/memos/memories/textual/prefer_text_memory/utils.py

@@ -1,3 +1,4 @@
+import json
 import re
 
 from memos.dependency import require_python_package
@@ -9,12 +10,36 @@ def convert_messages_to_string(messages: MessageList) -> str:
     """Convert a list of messages to a string."""
     message_text = ""
     for message in messages:
+        content = message.get("content", "")
+        content = (
+            content.strip()
+            if isinstance(content, str)
+            else json.dumps(content, ensure_ascii=False).strip()
+        )
+        if message["role"] == "system":
+            continue
         if message["role"] == "user":
-            message_text += f"Query: {message['content']}\n" if message["content"].strip() else ""
+            message_text += f"User: {content}\n" if content else ""
         elif message["role"] == "assistant":
-            message_text += f"Answer: {message['content']}\n" if message["content"].strip() else ""
-    message_text = message_text.strip()
-    return message_text
+            tool_calls = message.get("tool_calls", [])
+            tool_calls_str = (
+                f"[tool_calls]: {json.dumps(tool_calls, ensure_ascii=False)}" if tool_calls else ""
+            )
+            line_str = (
+                f"Assistant: {content} {tool_calls_str}".strip()
+                if content or tool_calls_str
+                else ""
+            )
+            message_text += f"{line_str}\n" if line_str else ""
+        elif message["role"] == "tool":
+            tool_call_id = message.get("tool_call_id", "")
+            line_str = (
+                f"Tool: {content} [tool_call_id]: {tool_call_id}".strip()
+                if tool_call_id
+                else f"Tool: {content}".strip()
+            )
+            message_text += f"{line_str}\n" if line_str else ""
+    return message_text.strip()
 
 
 @require_python_package(

src/memos/multi_mem_cube/single_cube.py

@@ -495,6 +495,13 @@ def _process_pref_mem(
         if os.getenv("ENABLE_PREFERENCE_MEMORY", "false").lower() != "true":
             return []
 
+        if add_req.messages is None or isinstance(add_req.messages, str):
+            return []
+
+        for message in add_req.messages:
+            if message.get("role", None) is None:
+                return []
+
         target_session_id = add_req.session_id or "default_session"
 
         if sync_mode == "async":