Thanks @tgxworld. I’ve seen examples of how to use DiscourseEvents to emulate Discourse native webhooks here and here. I will try to do that if there’s no other choice.
But this seems complex. I would love to have a one-liner, like what @pfaffman proposed. When you use the UI or the API to create a webhook, doesn’t Discourse call an internal function I could also use from my plugin.rb file?