diff --git a/backend/packages/harness/deerflow/agents/middlewares/billing_middleware.py b/backend/packages/harness/deerflow/agents/middlewares/billing_middleware.py
index bfbebc14..083f48ca 100644
--- a/backend/packages/harness/deerflow/agents/middlewares/billing_middleware.py
+++ b/backend/packages/harness/deerflow/agents/middlewares/billing_middleware.py
@@ -174,6 +174,7 @@ def _extract_run_id(request: ModelRequest) -> str | None:  # noqa: ARG001
 
 def _reserve_failure_message(status_code: int | None) -> str:
     if status_code in _blocking_reserve_code_set():
+        # TODO: 将账单错误文案迁移到国际化资源中，按语言返回提示。
         return "The account balance is insufficient for this model call."
     return "Billing reservation failed. Please try again later."