As per chat in the join.me session, I have a couple of questions/observations about the MPD flow we have been discussing:
Why are we using the Authorization Grant for the ticket, which is actually the context for the forthcoming authorization that the AS has to assert? Should we be initiating the Client's interaction with the AS at the Authorize endpoint, rather than the token endpoint?
How can the Client maintain a "token session" for Bob so that he doesn't have to reassert claims (and potentially, consent for claim use) every time he gets a new ticket for a future request? It was suggested after the call ended that we could send a consent token that the Client can send back with future requests. Could we issue a signed jwt token (analagous to OpenID Connect id_token, but issued by the UMA AS for presentation back to it, complete with all claims thus far acquired)?