Hi Steve,
While at it, it appeared to me that you don't need sieve for that
purpose. With the recent commit ([1], [2]), you can just use
movemail as follows:
movemail --keep --sync=uidnext --max-messages=100 \
imaps://user:pass@server maildir://$HOME/.mail/myaccount-test/INBOX
(change source mailbox name, of course). Options were selected to
provide a behavior closest to that of mbsync in your configuration.
Regards,
Sergey
[1]
https://cgit.git.savannah.gnu.org/cgit/mailutils.git/commit/?id=5bbf1b5bd18777824f7346a9e6bc9eb454376839
[2]
https://git.gnu.org.ua/mailutils.git/commit/?id=5bbf1b5bd18777824f7346a9e6bc9eb454376839
