I'd say our conversation right here is a good example. Most people understand static typing, most people understand DI. Once you have those, the only part left

I'd say our conversation right here is a good example. Most people understand static typing, most people understand DI. Once you have those, the only part left to understand is the concept of capabilities. If you have all of those, your example is clear and simple. Maybe adding a type annotation to show that fs is a FileSystem in main, but that's about it. I think you've done a good job of minimizing what's required for the average developer to go from not knowing about capabilities to using them.