This has me a little dumbfounded as either really profound or slightly misguided. How do you mean? As I am reading this you think a custom schema wont effect a

This has me a little dumbfounded as either really profound or slightly misguided. How do you mean? As I am reading this you think a custom schema wont effect an implementation, but how do you expect to implement an external service (API for example) without the required defined schema. That's kind of the definition of a schema in this scenario. Extending the schema might be another thing. But implementation can't work without adhering to the defined schema of the provider? Right?