diff --git a/aodh/api/__init__.py b/aodh/api/__init__.py
index 712d657cc..2c2cb3c3c 100644
--- a/aodh/api/__init__.py
+++ b/aodh/api/__init__.py
@@ -22,5 +22,6 @@ OPTS = [
     cfg.StrOpt(
         'auth_mode',
         default="keystone",
-        help="Authentication mode to use. Unset to disable authentication"),
+        choices=('keystone', 'noauth'),
+        help="Authentication mode to use."),
 ]