I’m part of the testing and feedback for the agent builder.
The integration into a process is not properly ready yet. There is a an activity available in studio where you can use an agent during a process, but its not feature complete. It doesn’t support persistence yet to wait for Tools or Escalations to be completed and gets stuck if an Escalation is deleted instead of completed as it waits endlessly.
I believe the target is March 3rd for the next wave of features that should include stuff.
In Studio you need to add the package for ‘Agents’ to use this basic version, I cannot remember the name but searching for Agent should make it easy to find.