Thanks to the link from @jleskovar-tyro (https://github.com/jleskovar-tyro/wanikani-oas-spec), I was able to quickly generate a Typescript library. The Typescript library is used under the Apache 2.0 license(https://swagger.io/license/)
This project will not be actively maintained, but if somebody wants to fork it and create a full CLI feel free (see LICENSE.md)