diff --git a/basis/debugger/debugger.factor b/basis/debugger/debugger.factor
index e1c23923a1..3cac57326a 100755
--- a/basis/debugger/debugger.factor
+++ b/basis/debugger/debugger.factor
@@ -205,6 +205,8 @@ M: bad-slot-value summary drop "Bad store to specialized slot" ;
 
 M: bad-slot-name summary drop "Bad slot name in object literal" ;
 
+M: bad-vocab-name summary drop "Vocab name cannot contain \":/\\ \"" ;
+
 M: no-math-method summary
     drop "No suitable arithmetic method" ;