[robertlagrant]

These seem arbitrary rules.

"Use internal status signaling" for example doesn't seem any better than deciding what status codes mean what; it's just a second layer of codes where the first one is now useless.

"Limit yourself to GET and POST." - delete and patch are pretty useful for documentation simplicity too. If there were a LIST verb that would be even handier, but nothing's perfect.

"build a protocol along the lines of your subject area" - I think you can do this (and well or badly) using REST or RPC forms.