That did the trick.
I looked at the user profile page to see what attributes are available.
I created simple mapping like this:
function (user, context, callback) {
const namespace = 'https://myapp.example.com/';
context.idToken[namespace + 'roles'] = user['urn:oid:1:3:6:1:4:1:5923:1:1:1:9'];
context.idToken[namespace + 'preferred_contact'] = 'N/A';
callback(null, user, context);
}
Thanks so much.