diff --git a/values/incubator-infra-gke-toolshed-prd-usc1-values.yaml b/values/incubator-infra-gke-toolshed-prd-usc1-values.yaml
index 9eb8c10..d3521eb 100644
--- a/values/incubator-infra-gke-toolshed-prd-usc1-values.yaml
+++ b/values/incubator-infra-gke-toolshed-prd-usc1-values.yaml
@@ -34,6 +34,16 @@ appSpec:
     namespace: argocd
     chartDir: argo-cd
     valuesDir: argocd-admin-prd
+    # Argo CD v3's own CRDs (applications, applicationsets, appprojects)
+    # embed large schemas, past the 256KiB last-applied-configuration limit
+    # a client-side apply writes — the same reason cert-manager and
+    # external-secrets use this.
+    serverSideApply: true
+    # And therefore the same stale-schema diff problem: see the contour
+    # entry. Once the upgrade lands, Argo CD's schema matches this cluster
+    # and this becomes belt-and-braces rather than load-bearing.
+    compareOptions:
+      - ServerSideDiff=true
   - name: gitea
     nameOverride: gitea
     namespace: gitea