Add |git cl description| to allow you to change the description in your favorite $EDITOR.

git_cl.py

Index: git_cl.py
===================================================================
--- git_cl.py	(revision 200864)
+++ git_cl.py	(working copy)
@@ -1120,6 +1120,17 @@
   return 0
 
 
+def CMDdescription(parser, args):
+  """brings up the editor for the current CL's description."""
+  cl = Changelist()
+  if not cl.GetIssue():
+    DieWithError('This branch has no associated changelist.')
+  description = ChangeDescription(cl.GetDescription())
+  description.prompt()
+  cl.UpdateDescription(description.description)
+  return 0
+
+
 def CreateDescriptionFromLog(args):
   """Pulls out the commit log to use as a base for the CL description."""
   log_args = []