Grant code in app-to-app Alexa linking flow?


I’m implementing app-to-app linking for my Alexa skill following the guide here:

and I’m currently at step 5 where the official guide is suggesting to “get the user’s authorization code” from your own backend server. I’m not seeing anywhere that this is possible in the Auth0 docs (could be missing something) and this seems to go against OAuth 2.0 since it’s generating a grant code on the user’s behalf.

One idea that I had was to just have the app pass the auth0 grant code along with the Amazon auth code in the diagram on the guide linked above. I’ve got a react native app and I’m not seeing a way to generate this grant code within the app. It appears I need to open a link in a web browser, get consent from the user (who will probably have to login, despite being logged into the app), then redirect back to the app with the grant code. This seems like a roundabout way of doing things, especially since the user is logged in already.

I also feel like the user pressing a button to link with their Alexa isn’t explicit enough in regards to consent to generate an auth0 grant code, which the Alexa guide is suggesting.

Is there something I’m missing? Has anyone implemented app-to-app linking with auth0 inside of a mobile application?