diff --git a/src/callbacks.py b/src/callbacks.py
index 03ef6eda0..d209afbd7 100644
--- a/src/callbacks.py
+++ b/src/callbacks.py
@@ -542,6 +542,9 @@ class IrcObjectProxy(RichReplyMethods):
     "A proxy object to allow proper nested of commands (even threaded ones)."
     def __init__(self, irc, msg, args, nested=0):
         log.verbose('IrcObjectProxy.__init__: %s' % args)
+        assert isinstance(args, list), \
+               'Args should be a list.  Don\'t call this with a string, it\s' \
+               'baaad.'
         self.irc = irc
         self.msg = msg
         self.nested = nested