A user tried to drain a shard and was moving a database which was primary on that shard. The move was unsuccessful as the nagios plugin they were using created a database in each shard with the same name and db.printShardingStatus() was incorrectly claiming that the shard to be drained was the only shard. When they tried to run movePrimary() this was the error message"

"errmsg" : "clone failed"

Can this error message be improved so that it provides a better indication as to what the error might be?