diff --git a/apps/api/src/services/incident_service.py b/apps/api/src/services/incident_service.py
index 532a1576..db752758 100644
--- a/apps/api/src/services/incident_service.py
+++ b/apps/api/src/services/incident_service.py
@@ -101,7 +101,7 @@ def extract_affected_services(labels: dict, target_resource: str) -> list[str]:
     return []
 
 
-def classify_alert_early(alertname: str, severity: str, _labels: dict) -> tuple[str, str]:
+def classify_alert_early(alertname: str, severity: str, labels: dict | None = None) -> tuple[str, str]:
     """
     ADR-073 Phase 2-2: 早期分診，在 LLM 分析前決定 alert_category + notification_type。
     防止 HostBackupFailed 等告警被誤路由到 K8s executor。