Oh! They can’t publish arbitrary web content on their own :) You have to give it “tools” (JSON schema representing something you’ll translate into a programmatic call), then, implement taking messages in that JSON schema and “doing the thing”, which in this case could mean anything from a POST to Tumblr to uploading to a server…
Actually, let me stop myself there. An alternative way to think about it without overwhelming with boring implementation details: what would you have to give me to allow me to publish arbitrary hypertext on a domain you own?
