We've just pushed the initial implementation of ad-hoc commands which can be used to configure bridges and bots, remote control clients, and register with gateways!

There's still a lot to do, but the initial implementation is already relatively complete and supports custom forms as well as displaying Out-of-Band URLs to the user (for example, to send them to a third party registration page in the browser) and simple notes.

Try it out and be sure to send us your feedback and bug reports on the issue tracker (https://mellium.im/issue/)!