[Users] running a command when receiving new mails for only a specific account

[Marco Moock]

Am 05.04.2024 schrieb Paul <paul at claws-mail.org>:

> On Fri, 5 Apr 2024 10:53:21 +0200
> Marco Moock <mm at dorfdsl.de> wrote: 
> 
> > I would like to run a script when a specific account receives new
> > mail. Is that possible?  
> 
> Yes, use an account-specific filtering rule with the 'Execute' action.

Thanks.
What is the condition that needs to be used so it applies to new
messages only and runs only one time?