diff --git a/app/assets/services/schemas.py b/app/assets/services/schemas.py
index d63c1f60d..b744283b2 100644
--- a/app/assets/services/schemas.py
+++ b/app/assets/services/schemas.py
@@ -23,10 +23,10 @@ class ReferenceData:
     file_path: str | None
     user_metadata: UserMetadata
     preview_id: str | None
+    created_at: datetime
+    updated_at: datetime
     system_metadata: dict[str, Any] | None = None
     prompt_id: str | None = None
-    created_at: datetime = None  # type: ignore[assignment]
-    updated_at: datetime = None  # type: ignore[assignment]
     last_access_time: datetime | None = None