diff --git a/scsh/scsh-interfaces.scm b/scsh/scsh-interfaces.scm
index f6e273a..e185a4f 100644
--- a/scsh/scsh-interfaces.scm
+++ b/scsh/scsh-interfaces.scm
@@ -406,6 +406,7 @@
 
 (define-interface scsh-user/group-db-interface
   (export user-info
+          user-info?
 	  user-info:name
 	  user-info:uid
 	  user-info:gid
@@ -416,6 +417,7 @@
 	  ->username
 
 	  group-info
+          group-info?
 	  group-info:name
 	  group-info:gid
 	  group-info:members