diff --git a/git-bzr b/git-bzr
index bd881d1..d0e86fe 100755
--- a/git-bzr
+++ b/git-bzr
@@ -385,8 +385,10 @@ def cmd_clone(args):
   (options, args) = parser.parse_args(args)
 
   # TODO(termie): command-line validation
-  url = args[0]
+  if not len(args):
+    die('You must provide an URL.')
 
+  url = args[0]
   if len(args) == 1:
     target = url.rpartition(':')[2].rpartition('/')[2]
   else:
@@ -640,8 +642,8 @@ def cmd_clear(args):
 
 
 def cmd_marks(args):
-  parser = optparse.OptionParser(usage='git bzr push <url>')
-  parser.description = ('Effectively a bzr push <url>')
+  parser = optparse.OptionParser(usage='git bzr marks')
+  parser.description = ('Print all marks')
   parser.add_option('--git', action='store_true', dest='git',
                     default=True,
                     help='show the git marks file')