What do you think about adding response codes for various failures?
Please consider these. Adding them would greatly raises the hopes of
intelligent error recovery in client implementations, something that
seems to be very difficult for IMAP clients. (Fortunately this is
much simpler than IMAP.)
Would using the ACAP response codes be a good idea?
They're probably the best thing going. They had several advantages
over IMAP with no real additional cost.
By the way, if you're not already using quoted strings for response
text, please consider that, too. It makes tokenization easier.
Our implentation always uses quoted strings but currently that isn't
required. It would seem requiring them for responses would make the
tokenization more difficult if anything.