For SMS prospecting within Uptics, the API does not give us information regarding open rates/bounces/etc, this would only be available for email steps inside of your sequences.
But, you still will be notified when there are SMS replies. This will show in the notification bell (upper right), inside the Sales Inbox (Left Menu), as well as inside the respective Contact Detail popouts.
Also, you would want to make sure you're aware that there are laws and legal ramifications associated with using SMS for cold outreach. You may read more about the same here: https://www.twilio.com/learn/call-and-text-marketing/guide-to-us-sms-compliance