On Health Loops.
Nothing is done twice. Each step saves its return value. A crash or deploy replays the saved value instead of the work.
Waiting is free. A run parks at a scan or a call and resumes from the same line when the person finishes.
Deploys do not break live work. Runs already in progress finish on the version they started with.
Questions
What is a durable workflow?
A durable workflow is an agent run whose every step is checkpointed, so a retry never repeats work that succeeded and the run can wait days for a person without holding compute.
What happens when a step fails?
The platform tries it once more after a second. A step that already succeeded is replayed, not rerun.
How long can a run wait?
Until the person finishes the scan or the call, or the timeout you set fires.