Does swagger-gradle-plugin work with Spring MVC? Or only JAX-RS?

I have an existing spring boot application using Swagger 1.5 annotations. The gradle plugin I was using to generate swagger docs no longer works. So I noticed swagger-core now provides a gradle plugin. I see it only supports Swagger 2 annotation so I converted the 1.x annotations to 2.x. That went smoothly. However, no matter what I do all I get is a file whose sole contents is:

openapi: 3.0.1

I notice the documentation mentions a lot about JAX-RS and seems to trigger off @PATH  or @GET/POST annotations. However, I have spring MVC annotations so don't have JAX-RS annotations. I do however have the swagger 2.0 annotations. So do I have to have JAX-RS annotations before the swagger-gradle-plugin will generate the documentation?

I don't want to use springfox, I simply want a static yml file with the api docs in it.

EDIT: I tried adding an OpenAPIDefinition annotation to my controller, and that was added to my yml file. So the controller is definitely being examined; however, none of my operations are being added to the generated yml file.