Not that there's _no_ way to transport it over the wire, it just requires the full environment (a JVM on the other end - because we have java-specific stuff lik

Not that there's _no_ way to transport it over the wire, it just requires the full environment (a JVM on the other end - because we have java-specific stuff like spark calls). I'd put it at an order-of-magnitude more complex than something declarative like a JSON schema which is pretty safe to execute anywhere. I don't think this is a really big failing of spec - I don't know of ANY validation tools that don't have to compromise between power/extensibility/ease-and-safety-of-execution-somewhere-else. Maybe if you implemented some kind of uber-validator in purely functional prolog or something?