Some emails just can't be forwarded based on from/to alone. Given there is already an extension to sieve for email forwarding i assume there are technical challenges there.

So, i would like to propose an alternate solution that would dramatically improve the forwarding functionality with hopefully very little lift.

I propose you add the ability to make the presence and/or absence of tags a forward condition option. This one additional condition would address a ton of open forwarding requests on here.

As an example user story, i subscribe to some journalists on substack. I want the full articles to go to my reader but i want the notifications and other contemt to stay in my inbox.

I can filter this correctly with sieve, putting them I'm appropriate folders with appropriate labels. That would be a lot of complexity to support in your forwarding rule ui.

But if you let me make the decision in sieve before it hits the forwarding rules then everything gets a lot simpler for everyone.