diff --git a/backend/open_webui/models/chats.py b/backend/open_webui/models/chats.py
index 243803de1d..64b318fa4d 100644
--- a/backend/open_webui/models/chats.py
+++ b/backend/open_webui/models/chats.py
@@ -6,7 +6,7 @@ import logging
 import re
 import time
 import uuid
-from typing import Literal
+from typing import Any, Literal
 
 # local imports
 from open_webui.env import ENABLE_ADMIN_CHAT_ACCESS
@@ -1071,13 +1071,13 @@ class ChatTable:
 
         return chat.chat.get('history', {}).get('messages', {}).get(message_id, {})
 
-    async def get_message_metadata_list(
+    async def get_message_metadata(
         self,
         chat_id: str,
         message_id: str,
         metadata_key: Literal['files', 'sources', 'embeds'],
-    ) -> list[dict]:
-        """Read one list-valued message field without rebuilding the whole history."""
+    ) -> Any | None:
+        """Read one message metadata field without rebuilding the whole history."""
         async with get_async_db_context() as db:
             # Read the column directly; some stored rows cannot be validated as full ChatMessageModel objects.
             result = await db.execute(
@@ -1086,14 +1086,14 @@ class ChatTable:
             metadata_row = result.first()
 
         if metadata_row is not None:
-            return metadata_row[0] or []
+            return metadata_row[0]
 
         chat = await self.get_chat_by_id(chat_id)
         if chat is None:
-            return []
+            return None
 
         message = chat.chat.get('history', {}).get('messages', {}).get(message_id, {})
-        return message.get(metadata_key) or []
+        return message.get(metadata_key)
 
     async def upsert_message_to_chat_by_id_and_message_id(
         self, id: str, message_id: str, message: dict, *, touch: bool = True
diff --git a/backend/open_webui/socket/main.py b/backend/open_webui/socket/main.py
index 7f06ecc2d0..58f049dc91 100644
--- a/backend/open_webui/socket/main.py
+++ b/backend/open_webui/socket/main.py
@@ -1074,8 +1074,9 @@ async def get_event_emitter(request_info, update_db=True):
                 embeds = event_payload.get('embeds', [])
 
                 if not event_payload.get('replace', False):
-                    existing_embeds = await Chats.get_message_metadata_list(chat_id, message_id, 'embeds')
-                    embeds.extend(existing_embeds)
+                    existing_embeds = await Chats.get_message_metadata(chat_id, message_id, 'embeds')
+                    if isinstance(existing_embeds, list):
+                        embeds.extend(existing_embeds)
 
                 await Chats.upsert_message_to_chat_by_id_and_message_id(
                     chat_id,
@@ -1088,8 +1089,9 @@ async def get_event_emitter(request_info, update_db=True):
 
             elif event_type == 'files':
                 files = event_data.get('data', {}).get('files', [])
-                existing_files = await Chats.get_message_metadata_list(chat_id, message_id, 'files')
-                files.extend(existing_files)
+                existing_files = await Chats.get_message_metadata(chat_id, message_id, 'files')
+                if isinstance(existing_files, list):
+                    files.extend(existing_files)
 
                 await Chats.upsert_message_to_chat_by_id_and_message_id(
                     chat_id,
@@ -1103,7 +1105,9 @@ async def get_event_emitter(request_info, update_db=True):
             elif event_type in ('source', 'citation'):
                 data = event_data.get('data', {})
                 if data.get('type') is None:
-                    sources = await Chats.get_message_metadata_list(chat_id, message_id, 'sources')
+                    sources = await Chats.get_message_metadata(chat_id, message_id, 'sources')
+                    if not isinstance(sources, list):
+                        sources = []
                     sources.append(data)
 
                     await Chats.upsert_message_to_chat_by_id_and_message_id(