(I'm one of the creators.)<p>If you're curious about how we did it, take a look at <a href="https://github.com/46Bit/irepl" rel="nofollow">https://github.com/46Bit/irepl</a>. Messages Beta for Mac still has AppleScript bindings from iChat. We're (ab)using them to pass the iMessages to Heist and then reply.