In prefect.yaml if I use a build stage, is it only run once when I deploy it? Or is the build stage run every time the flow runs? I am trying to make a shell script to register a custom Block but only once and prior to the first time the flow which will use it is run.

Hey Russell! The build step should only run when you first deploy your flow(s), not every time the flow is executed

Thank you. That is what I needed.