diff --git a/apps/api/src/services/auto_repair_service.py b/apps/api/src/services/auto_repair_service.py
index bbcc53ac..4c29510c 100644
--- a/apps/api/src/services/auto_repair_service.py
+++ b/apps/api/src/services/auto_repair_service.py
@@ -517,7 +517,11 @@ class AutoRepairService:
 
         if incident.signals:
             for signal in incident.signals:
-                alert_names.append(signal.alert_name)
+                # 優先用 labels["alertname"]（原始 Prometheus alertname），
+                # fallback 到 signal.alert_name（可能是 "custom" 等類別值）
+                # (2026-04-09 Claude Sonnet 4.6 Asia/Taipei, L7 E2E 修正)
+                raw_alertname = signal.labels.get("alertname") if signal.labels else None
+                alert_names.append(raw_alertname or signal.alert_name)
                 # 從 annotations 提取關鍵字
                 if signal.annotations:
                     for value in signal.annotations.values():