> An activity must encapsulate something much higher level than a single IO operation. So something like "Configure BGP on a router", "Start a VM" etc. It needs to be able to handle retries and thus be idempotent.

I was referring to the workflows, that is, writing the workflows in managed languages, not the activities.

Out of curiosity, are you working full-time on this? I'm working part-time on the same problem, looking to go full time soon, and it's interesting to see how the same ideas are popping up somewhat independently across different projects :) let me know if you're interested in chatting!