diff --git a/veadk/database/kv/redis_database.py b/veadk/database/kv/redis_database.py
index 1173615c..c79144aa 100644
--- a/veadk/database/kv/redis_database.py
+++ b/veadk/database/kv/redis_database.py
@@ -150,7 +150,10 @@ def list_docs(self, key: str) -> list[dict]:
         """
         try:
             items = self._client.lrange(key, 0, -1)
-            return [{"id": str(i), "content": item} for i, item in enumerate(items)]
+            return [
+                {"id": str(i), "content": item, "metadata": {}}
+                for i, item in enumerate(items)
+            ]
         except Exception as e:
             logger.error(f"Failed to list documents from key {key}: {e}")
             return []
diff --git a/veadk/database/local_database.py b/veadk/database/local_database.py
index 172753a6..45ac2e1d 100644
--- a/veadk/database/local_database.py
+++ b/veadk/database/local_database.py
@@ -46,7 +46,10 @@ def add(self, texts: list[str], **kwargs: Any):
         return self.add_texts(texts)
 
     def list_docs(self, **kwargs: Any) -> list[dict]:
-        return [{"id": id, "content": content} for id, content in self.data.items()]
+        return [
+            {"id": id, "content": content, "metadata": {}}
+            for id, content in self.data.items()
+        ]
 
     def delete_doc(self, id: str, **kwargs: Any):
         if id not in self.data:
diff --git a/veadk/database/relational/mysql_database.py b/veadk/database/relational/mysql_database.py
index 9b9eda5c..644be67e 100644
--- a/veadk/database/relational/mysql_database.py
+++ b/veadk/database/relational/mysql_database.py
@@ -162,7 +162,8 @@ def list_docs(self, table: str, offset: int = 0, limit: int = 100) -> list[dict]
                 cursor.execute(sql, (limit, offset))
                 results = cursor.fetchall()
                 return [
-                    {"id": str(row["id"]), "content": row["data"]} for row in results
+                    {"id": str(row["id"]), "content": row["data"], "metadata": {}}
+                    for row in results
                 ]
         except Exception as e:
             logger.error(f"Failed to list documents from table {table}: {e}")
diff --git a/veadk/database/vector/opensearch_vector_database.py b/veadk/database/vector/opensearch_vector_database.py
index 68061e2d..4ba71d7b 100644
--- a/veadk/database/vector/opensearch_vector_database.py
+++ b/veadk/database/vector/opensearch_vector_database.py
@@ -235,6 +235,7 @@ def list_docs(
             {
                 "id": hit["_id"],
                 "content": hit["_source"]["page_content"],
+                "metadata": {},
             }
             for hit in response["hits"]["hits"]
         ]
diff --git a/veadk/database/viking/viking_database.py b/veadk/database/viking/viking_database.py
index 61a3048a..1e0cac1c 100644
--- a/veadk/database/viking/viking_database.py
+++ b/veadk/database/viking/viking_database.py
@@ -434,7 +434,11 @@ def list_docs(
             raise ValueError(f"Error in list_docs: {result['message']}")
 
         data = [
-            {"id": res["point_id"], "content": res["content"]}
+            {
+                "id": res["point_id"],
+                "content": res["content"],
+                "metadata": res["doc_info"],
+            }
             for res in result["data"]["point_list"]
         ]
         return data