The auto-ack notification feature should support bang commands. Any ack string starting with '!' is considered to be a bang command. Snarl will provide some default ones (e.g. !show_missed_panel, !configure x.app, !configure y.style, etc.) but 3rd party bang addons can also be used. The current thinking is that 3rd party addons will be managed via a melon resource rather than a bespoke Snarl feature.
Other possible bang commands:
!dnd on|off
!stop
!start
!prefs [page # to open]
Closed. 3rd party bang extensions may be implemented in the future.