For those using CPI, you can now achieve a partial Smartthings integration via the CPI Automations leveraging Alarm.com as their rules engine and remote access service.
Instructions for the integration can be found here:
This can also expose Arm(Away/Stay) and Disarm switches to Alexa, so enable Disarm at your own risk. This will allow you to bypass the Alexa CPI Skill utterance, and use a direct utterance (e.g. “Alexa Arm Away on”).
Also, this does not currently support sensor monitoring or automation device commands. It only handles the arm/disarm of your security system.