I recommend if you have not worked with Sync before then you should follow this guide first. This guide will help you set up the Voyager Server repo and run the keycloak example server https://github.com/aerogear/apollo-voyager-server/blob/master/doc/guides/examples.md#apollo-voyager-server-examples

In that example, you will see how the hasRole directive is used. https://github.com/aerogear/apollo-voyager-server/blob/master/examples/keycloak/server.js#L22

The @hasRole directive was documented before when we were building sync as a service. https://github.com/aerogear/mobile-docs/blob/master/modules/ROOT/pages/_partials/sync/authorization.adoc

We need to ensure that the document is up to date and makes sense for the Apollo Voyager Server Framework.