diff --git a/services/jenkins/kustomization.yaml b/services/jenkins/kustomization.yaml
index 5f3e0554..4e00efcb 100644
--- a/services/jenkins/kustomization.yaml
+++ b/services/jenkins/kustomization.yaml
@@ -18,6 +18,7 @@ resources:
   - deployment.yaml
   - service.yaml
   - ingress.yaml
+  - lesavka-userns-probe.yaml
 
 configMapGenerator:
   - name: jenkins-jcasc-revision
diff --git a/services/jenkins/lesavka-userns-probe.yaml b/services/jenkins/lesavka-userns-probe.yaml
new file mode 100644
index 00000000..03958421
--- /dev/null
+++ b/services/jenkins/lesavka-userns-probe.yaml
@@ -0,0 +1,56 @@
+# services/jenkins/lesavka-userns-probe.yaml
+# Qualification only: never relax the compiler pod to bypass a failed gate.
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: lesavka-userns-probe-1
+  namespace: jenkins
+spec:
+  backoffLimit: 0
+  activeDeadlineSeconds: 120
+  template:
+    metadata:
+      labels:
+        atlas.bstein.dev/workload: lesavka-userns-probe
+    spec:
+      restartPolicy: Never
+      hostUsers: false
+      automountServiceAccountToken: false
+      enableServiceLinks: false
+      nodeSelector:
+        kubernetes.io/hostname: titan-22
+        kubernetes.io/arch: amd64
+      imagePullSecrets:
+        - name: harbor-bstein-robot
+      securityContext:
+        runAsNonRoot: true
+        runAsUser: 1000
+        runAsGroup: 1000
+        seccompProfile:
+          type: RuntimeDefault
+      containers:
+        - name: probe
+          image: registry.bstein.dev/bstein/lesavka-ci@sha256:7d3a2548ef0df8da053a2e2939675f5a3cf23e26517828e5fa9a3185911a8e75
+          securityContext:
+            allowPrivilegeEscalation: false
+            readOnlyRootFilesystem: true
+            capabilities:
+              drop: ["ALL"]
+          resources:
+            requests: {cpu: 10m, memory: 32Mi}
+            limits: {cpu: 100m, memory: 64Mi, ephemeral-storage: 32Mi}
+          command: ["python3", "-I", "-c"]
+          args:
+            - |
+              import json, os
+              from pathlib import Path
+              maps = {name: [[int(v) for v in line.split()] for line in
+                      Path('/proc/self/' + name).read_text().splitlines()]
+                      for name in ('uid_map', 'gid_map')}
+              assert os.geteuid() == 1000 and os.getegid() == 1000
+              for entries in maps.values():
+                  assert len(entries) == 1
+                  inside, outside, count = entries[0]
+                  assert inside == 0 and outside >= 65536 and count >= 65536
+              print(json.dumps({'pod_user_namespace': 'pass', 'maps': maps,
+                    'scope': 'outer mapping only; nested test namespaces unqualified'}))