diff --git a/project.clj b/project.clj
index b04f419..8b5f76c 100644
--- a/project.clj
+++ b/project.clj
@@ -5,7 +5,7 @@
             :url "https://www.apache.org/licenses/LICENSE-2.0.html"}
   :dependencies [[org.clojure/clojure "1.10.3"]
                  [org.clojure/tools.reader "1.3.6"]
-                 [org.domaindrivenarchitecture/c4k-common-clj "6.0.0"]]
+                 [org.domaindrivenarchitecture/c4k-common-clj "6.0.1"]]
   :target-path "target/%s/"
   :source-paths ["src/main/cljc"
                  "src/main/clj"]
diff --git a/src/main/cljc/dda/c4k_keycloak/core.cljc b/src/main/cljc/dda/c4k_keycloak/core.cljc
index ce6cc8f..49d7e69 100644
--- a/src/main/cljc/dda/c4k_keycloak/core.cljc
+++ b/src/main/cljc/dda/c4k_keycloak/core.cljc
@@ -14,16 +14,16 @@
 
 (def config-defaults {:issuer "staging"})
 
-(s/def ::config (s/keys :req-un [::kc/fqdn]
-                        :opt-un [::kc/issuer
-                                 ::mon/config]))
+(def config? (s/keys :req-un [::kc/fqdn]
+                     :opt-un [::kc/issuer
+                              ::mon/mon-cfg]))
 
 (def auth? (s/keys :req-un [::kc/keycloak-admin-user ::kc/keycloak-admin-password
                             ::postgres/postgres-db-user ::postgres/postgres-db-password]
                    :opt-un [::mon/auth]))
 
 (defn-spec k8s-objects cp/map-or-seq?
-  [config ::config
+  [config config?
    auth auth?]
   (map yaml/to-string
        (filter
diff --git a/src/test/cljc/dda/c4k_keycloak/core_test.cljc b/src/test/cljc/dda/c4k_keycloak/core_test.cljc
index fdc25c6..c40c1d2 100644
--- a/src/test/cljc/dda/c4k_keycloak/core_test.cljc
+++ b/src/test/cljc/dda/c4k_keycloak/core_test.cljc
@@ -16,5 +16,6 @@
 
 ;; TODO: 2023.01.27 - jem: may not validate k3s-cluster-name entries ... find out what's wrong.
 (deftest validate-valid-resources
-  (is (s/valid? ::cut/config (yaml/load-as-edn "keycloak-test/valid-config.yaml")))
-  (is (s/valid? cut/auth? (yaml/load-as-edn "keycloak-test/valid-auth.yaml"))))
\ No newline at end of file
+  (is (s/valid? cut/config? (yaml/load-as-edn "keycloak-test/valid-config.yaml")))
+  (is (s/valid? cut/auth? (yaml/load-as-edn "keycloak-test/valid-auth.yaml")))
+  (is (not (s/valid? cut/config? (yaml/load-as-edn "keycloak-test/invalid-config.yaml")))))
\ No newline at end of file
diff --git a/src/test/resources/keycloak-test/invalid-config.yaml b/src/test/resources/keycloak-test/invalid-config.yaml
new file mode 100644
index 0000000..2ff8447
--- /dev/null
+++ b/src/test/resources/keycloak-test/invalid-config.yaml
@@ -0,0 +1,6 @@
+fqdn: "keycloak.test.meissa-gmbh.de"
+issuer: "staging"
+mon-cfg:
+  grafana-clod-url: "url-for-your-prom-remote-write-endpoint"
+  cluster-nam: "keycloak"
+  cluster-stage: "none"
\ No newline at end of file
diff --git a/src/test/resources/keycloak-test/valid-config.yaml b/src/test/resources/keycloak-test/valid-config.yaml
index d995606..4aa1c76 100644
--- a/src/test/resources/keycloak-test/valid-config.yaml
+++ b/src/test/resources/keycloak-test/valid-config.yaml
@@ -3,4 +3,4 @@ issuer: "staging"
 mon-cfg:
   grafana-cloud-url: "url-for-your-prom-remote-write-endpoint"
   cluster-name: "keycloak"
-  cluster-stage: :test
\ No newline at end of file
+  cluster-stage: "test"
\ No newline at end of file