You may have an idea, sure, but the alternative is to codegen a new instance of the client library any time anything changes rather than keeping up to date with

You may have an idea, sure, but the alternative is to codegen a new instance of the client library any time anything changes rather than keeping up to date with the API as it evolves and exists. (The moral equivalent is pulling a WSDL during app startup and making sure that you're presenting a correct interface to it.) I full-stop don't do codegen in any project under any circumstance that is not done strictly within the workflow of a build tool (i.e., a Maven generated-sources gizmo). OpenAPI's options are pretty much all exactly not that: all the codegen options's happy paths seem to be vendoring generated code. And that makes me itch, too.