How to get access to Sign in with Vercel API Permissions (private beta) ?

Sign in with Vercel (GA) is working well for us — OAuth/OIDC flow, identity scopes (openid / email / profile / offline_access), token exchange, and refresh are all set up.

Our blocker is the next layer: we need the access token to call the REST API on the connected user’s behalf — specifically Projects, Domains, and Deployments (add/verify a project domain, read domain config, create a deployment). Per the docs those API Permissions are in private beta, and they aren’t exposed in our app’s Permissions settings yet — we only see the identity scopes.

What’s the process to request access to the private-beta API Permissions?