What is any good API management library if it doesn't do validation of the server communication? This was not built directly into the api-layer, but can be easily added using any 3rd party data library that you want. The sample.test.ts file provided uses AJV to perform JSON schema validation.
If you are using client-side caching and data validation, it is recommended to call your validator first, then wrap the validation call in a memoization call so that you only run validation on an actual API call (instead of every time). NOTE: Validation is not run on your overrides unless you explicitly wrap them in validation code also