diff --git a/oidc/class/oidc.class.php b/oidc/class/oidc.class.php
index 12fa2af..ef34e4d 100644
--- a/oidc/class/oidc.class.php
+++ b/oidc/class/oidc.class.php
@@ -101,6 +101,20 @@ class OIDC extends FOGController
         'issuer',
         'clientId'
     ];
+    /**
+     * clientId ends in "id" without being a foreign key.
+     *
+     * FOGController::save() reads a key ending in "id" as an integer id
+     * unless the model says otherwise. A client id is a string the provider
+     * chooses -- "fog-web", or a GUID on Entra -- so without this every
+     * create failed with "Required database field is empty: clientId" about
+     * a field that was filled in. Needs fogproject#1153.
+     *
+     * @var array
+     */
+    protected $databaseFieldsNotInt = [
+        'clientId'
+    ];
     /**
      * Validate before storing.
      *
diff --git a/tests/oidc-provider-safety.test.php b/tests/oidc-provider-safety.test.php
index 5b2b803..ebfe37c 100644
--- a/tests/oidc-provider-safety.test.php
+++ b/tests/oidc-provider-safety.test.php
@@ -297,6 +297,29 @@ function () {
     );
 }
 
+/*
+ * clientId must stay declared as a string.
+ *
+ * FOGController::save() reads any key ending in "id" as an integer foreign
+ * key unless the model opts out, and clientId is required -- so dropping the
+ * opt-out does not degrade anything, it makes creating a provider impossible,
+ * reported as "Required database field is empty: clientId" about a field the
+ * admin filled in. That is a whole feature off, so it is pinned here rather
+ * than left to be rediscovered. Needs fogproject#1153.
+ */
+$declared = [];
+if (property_exists('OIDC', 'databaseFieldsNotInt')) {
+    $notInt = new \ReflectionProperty('OIDC', 'databaseFieldsNotInt');
+    $notInt->setAccessible(true);
+    $declared = array_map('strtolower', (array)$notInt->getValue(new OIDC()));
+}
+if (!in_array('clientid', $declared, true)) {
+    fail(
+        'OIDC does not declare clientId in $databaseFieldsNotInt, so '
+        . 'save() will reject every provider whose client id is not a number'
+    );
+}
+
 if (count($fails) > 0) {
     fwrite(STDERR, 'FAIL: ' . count($fails) . " problem(s):\n");
     foreach ($fails as $f) {