diff --git a/rcl_interfaces/msg/SetParametersResult.msg b/rcl_interfaces/msg/SetParametersResult.msg
index 4c9e944b..8dd4192b 100644
--- a/rcl_interfaces/msg/SetParametersResult.msg
+++ b/rcl_interfaces/msg/SetParametersResult.msg
@@ -2,6 +2,6 @@
 # successfully. A false value indicates the change was rejected.
 bool successful
 
-# Reason why the setting was either successful or a failure. This should only be
-# used for logging and user interfaces.
+# Reason why the setting was a failure. On success, the contents of this field
+# are undefined.  This should only be used for logging and user interfaces.
 string reason