diff --git a/auth.capnp b/auth.capnp
index 25fd49d..bc65d54 100644
--- a/auth.capnp
+++ b/auth.capnp
@@ -53,7 +53,7 @@ interface Authentication {
     # A server receiving an abort after sending an outcome but before
     # receiving any other message MUST respect the abort.
 
-    whoami @4 () -> ( you :Api.User );
+    whoami @4 () -> ( you :Api.User, dummy :UInt8 = 0  );
     # Returns NULL if not authenticated and an User object if authenticated.
 }