Q: How do global scrips work in RT?

Answer

Out of the box, global scrips are enabled for all queues and perform some common tasks. The drawback with this is that they can't be disabled on a queue-by-queue basis. Also, if you create an equivalent scrip (e.g. your own reply on creation of a ticket) both your scrip and the global one are executed resulting in redundant email transactions.

The MIT implementation of RT sets the global scrips to to "local" scrips. This means that they can be turned off on a queue-by-queue basis and/or queue administrators can create their own equivalent scrips that are executed in place of what used to be global scrips, not in addition to them.

Below is a list of the default scrips provided with RT:

On Create, Autoreply to Requestors with Global Template: Autoreply: When a ticket is created, email notification is sent to the Requestor.
On Create, Notify AdminCcs with Global Template: Transaction: When a ticket is created, email notification goes to the Admin Cc's that a ticket has been created.
On Correspond, Notify AdminCcs with Global Template: Admin Correspondence: When a Watcher type of Admin Cc adds a reply to a ticket, email notification is sent.
On Correspond, Notify Requestors and Ccs with Global Template: Correspondence: When a Watcher adds at public reply to a ticket, the Requestor and any other watchers (i.e., Cc's and Admin Cc's) receive email notification.
On Comment, Notify AdminCcs as Comment with Global Template: Admin Comment: When a comment is added to the ticket, email notification is all Admin Cc's.
On Resolve, Notify Requestors with Global Template: Resolved: When a ticket is completed, a form letter is sent to the Requestor stating that work is completed.