Some exceptions are returned by webob (and other frameworks) as HTML. The client should strip the tags to make the error message more explicit and easier to read.
For example:
2015-01-30 15:15:30.513 | ++ openstack --os-token 3da24a51127b4c5da73570cc35b5afd7 --os-url http://10.\
0.3.15:9292 image create ubuntu-14.04-server-cloudimg-amd64-kernel --public --container-format aki --d\
isk-format aki
2015-01-30 15:15:30.514 | ++ get_field 2
2015-01-30 15:15:30.517 | ++ grep ' id '
2015-01-30 15:15:30.519 | ++ local data field
2015-01-30 15:15:30.521 | ++ read data
2015-01-30 15:15:39.176 | ERROR: openstack <html>
2015-01-30 15:15:39.177 | <head>
2015-01-30 15:15:39.177 | <title>401 Unauthorized</title>
2015-01-30 15:15:39.177 | </head>
2015-01-30 15:15:39.177 | <body>
2015-01-30 15:15:39.177 | <h1>401 Unauthorized</h1>
2015-01-30 15:15:39.177 | This server could not verify that you are authorized to access the documen\
t you requested. Either you supplied the wrong credentials (e.g., bad password), or your browser does \
not understand how to supply the credentials required.<br /><br />
Ian, is this still a bug? I couldn't reproduce it with that command.