This might be harder than I thought. Creating a dummy google account to act as the receiver seems off the table. All of Google's APIs require OAuth or some manual way for the user to sign in. There is no way to make a pure bot account, and also no good way to automate login without being slapped by a ban.

I think the only real way to do this would be @BTullis's idea of sending alert emails to some mail server we deploy and then we can either process it within our own systems or build some endpoint on the current toolforge web app to receive some payload so we can store it in toolforge's database systems a little bit longer (although that will always be a ticking time bomb since they have a cap of 2GB per tool)