Ah... OK, now I understand.  Yes, you're going to run into a problem of multiple messages. If the original message is not a bangsy message, then it will hit the chat. Any passive listener script can output its own message, but it can't intercept that first message. On the other hand, a bangsy message means a dedicated script (or at least using something like the Metascript Toolbox). That can pre-empt the first roll, but it requires an active rewrite of every roll it would interact with.  One thing you might look into, before going the path of your own script, would be Customizable Roll Listener. IIRC, you instruct it with combinations of who is sending the message and what roll template to watch for, and you associate with that combination a new command line. When it sees those combinations come across the transom, it issues the command you've associated.  In your case, that could be as simple as outputting a message to remember to decrement by X-amount (you could probably still use the Fetch construction I mentioned, above, to get the value)... or, depending on the syntax available to you from CRL, you might even be able to reference a roll in the output of the first message. If you can reference the roll, then you can probably use metascript constructions to perform math on the roll and produce a new output (basically performing the reduction yourself, and producing the final result in the CRL message).