diff --git a/argocd/railiance01/applications/ops-mason-builder.application.yaml b/argocd/railiance01/applications/ops-mason-builder.application.yaml
new file mode 100644
index 0000000..f14f5c0
--- /dev/null
+++ b/argocd/railiance01/applications/ops-mason-builder.application.yaml
@@ -0,0 +1,27 @@
+# railiance01 child Application (MASON-IN-0006 choice (b), decision
+# 30d29060-8d14-4a8e-9cde-34aa826eb8d1). Scoped ops-mason builder identity.
+# No automated sync, no finalizer; targetRevision is the commit that
+# introduced the manifests.
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: ops-mason-builder
+  namespace: argocd
+  labels:
+    app.kubernetes.io/part-of: railiance-gitops
+    railiance-platform/component: ops-mason-builder
+  annotations:
+    argocd.argoproj.io/sync-wave: "10"
+spec:
+  project: railiance-platform-addons
+  source:
+    repoURL: https://forgejo.coulomb.social/coulomb/railiance-platform.git
+    targetRevision: bd6660a91672c76b78e017c22394705381d8767d
+    path: argocd/platform-addons/ops-mason-builder
+  destination:
+    server: https://kubernetes.default.svc
+    namespace: default
+  syncPolicy:
+    syncOptions:
+      - ApplyOutOfSyncOnly=true
+      - PruneLast=true
diff --git a/tests/test_ops_mason_builder_rbac.py b/tests/test_ops_mason_builder_rbac.py
index 1ab0f33..ab7e22b 100644
--- a/tests/test_ops_mason_builder_rbac.py
+++ b/tests/test_ops_mason_builder_rbac.py
@@ -2,14 +2,16 @@
 
 Parses the GitOps manifests and asserts the founder's 2026-10-22 boundary:
 the five granted rules only, no forbidden resources, no escalate/bind/impersonate,
-no wildcards, and a User subject with no ServiceAccount.
+no wildcards, a User subject with no ServiceAccount, and a manual, pinned Application.
 """
 from pathlib import Path
+import re
 
 import yaml
 
 ROOT = Path(__file__).resolve().parents[1]
 ADDON = ROOT / "argocd/platform-addons/ops-mason-builder"
+APP = ROOT / "argocd/railiance01/applications/ops-mason-builder.application.yaml"
 
 WRITE_VERBS = ["create", "get", "list", "watch", "update", "patch", "delete"]
 READ_VERBS = ["get", "list", "watch"]
@@ -87,3 +89,13 @@ def test_binding_targets_only_the_user():
     assert binding["subjects"] == [{"kind": "User", "name": "ops-mason-builder",
                                     "apiGroup": "rbac.authorization.k8s.io"}]
     assert all(s["kind"] != "ServiceAccount" for s in binding["subjects"])
+
+
+def test_application_manual_and_pinned():
+    app = yaml.safe_load(APP.read_text())
+    spec = app["spec"]
+    assert spec["project"] == "railiance-platform-addons"
+    assert spec["source"]["path"] == "argocd/platform-addons/ops-mason-builder"
+    assert re.fullmatch(r"[0-9a-f]{40}", spec["source"]["targetRevision"])
+    assert "automated" not in spec.get("syncPolicy", {})
+    assert "finalizers" not in app["metadata"]