Invoking Agent from Workflow

I added an Invoke Agent block to a workflow. I have 2 questions around setting this up:

  1. Why doesn’t Sync have the same input options as Async (ie JSON and GUI)?
  2. If I wanted to use Async GUI, how do I setup the agent’s input parameters, so that something shows up here?

Overall, I’m just tinkering at the moment, and user interface for this block didn’t make sense to me.