In your muttrc you should have something like the following:

set query_command = "goobook query '%s'"
bind editor <tab> complete
bind editor ^T    complete-query

and if auto-completion of aliases isn't working make sure you don't have:

bind editor <tab> complete-query
bind editor ^T    complete

Note that the complete-query vs complete. Ctrl-T runs your query_command whereas tab auto-completes as appropriate (likely from your alias list).

That took too long to figure out…