diff --git a/platform-config/kustomization.yaml b/platform-config/kustomization.yaml
index 75b474e..d2a02a4 100644
--- a/platform-config/kustomization.yaml
+++ b/platform-config/kustomization.yaml
@@ -29,3 +29,5 @@ resources:
   # cilium: L2 LB IP pool + announcement policy (cilium.io CRDs already registered by Cilium)
   - cilium/l2-ip-pool.yaml
   - cilium/l2-announcement-policy.yaml
+  # monitoring: PrometheusRule alert rules (need monitoring.coreos.com CRDs from kube-prometheus-stack)
+  - ../platform/monitoring/alerts.yaml
diff --git a/platform/monitoring/kustomization.yaml b/platform/monitoring/kustomization.yaml
index 11ec3ce..5a573be 100644
--- a/platform/monitoring/kustomization.yaml
+++ b/platform/monitoring/kustomization.yaml
@@ -7,6 +7,8 @@ resources:
   - kube-prometheus-stack.yaml
   - loki.yaml
   - alloy.yaml
-  - alerts.yaml
+  # NOTE: alerts.yaml (PrometheusRule CRs) needs the monitoring.coreos.com CRDs that the
+  # kube-prometheus-stack HelmRelease above installs → applied by the platform-config Kustomization
+  # (dependsOn platform) so the CRDs exist first. File stays here for locality.
   - grafana-admin-credentials.sops.yaml
   - alertmanager-smtp.sops.yaml