run a script after you roll on the character sheet

Is there a command similar to on("change:<attribute_name>)  that works with <roll_name>. I'm trying to find a way to project on sanity. The idea is that I could reduce my sanity loss projecting on one bound (reducing it's value by 1d4). To do so I need to have a temporary value for the sanity (done) and modified it with the value of my roll. However, whatever I try I cannot save the roll value as a variable to be used in modifying other attributes when a dice is rolled.  Note: I'm trying to do it using only the character sheet script 

Maybe a better question would be: How can I save the result of a button roll in my character sheet into an hidden attribute? (so I can use on("change:hidden_attr"). I might be really stupid but I cannot figure it out by myself (I was thinking to go and parse the the msg screen but I need to be sure it's the roll I'm looking for)

You can't do that using sheet workers, that's API territory.

Damn... I wanted to put everything I could in the character sheet so every user can do it. I guess I'll let them do it manually :/

on('chat:message') will pick up the roll (as well as every other message sent to chat). You can then parse the message to find out if a roll was made.