[MlMt] Run a script in a mailbox rule?

[Randall Meadows]

I want to run a script (bash/zsh [preferred] or AppleScript, et al.) 
whenever a new incoming message matches certain conditions I have 
defined in a rule on a mailbox.

I see the Run Command action in the rules editor, but that pulls from 
the Bundles I've enabled in the Bundles prefpane, and none of them seem 
to be able to run a script as an action.  Do I have to create my own 
Bundle to do this, or is there something else I'm missing?


Thanks!
randy