This is great, but I noticed that the output doesn't fully support OpenAPI 3.0.0, particularly the use of "oneOf" responses. I believe it's because you're calling out to swagger-ui and swagger-ui doesn't support these: https://github.com/swagger-api/swagger-ui/issues/3803

A lot of APIs in the wild actually do utilize oneOf responses (e.g. for returning rich structured errors that have an enum and a human-readable description but which all share the same HTTP status code) -- I know at least at $DAYJOB this was a major deterrent from using OpenAPI.