One of the biggest changes that you might notice is the clean separation between the MCP server being a Resource Provider (RP) and Authorization Server (AS). The MCP client will be able to discover this document and then use the declared authorization server (can be anything - Entra ID, Okta, Auth0, or a myriad of others) to kickstart the authorization code flow with Proof Key for Code Exchange (PKCE). You will still need to ensure that the AS supports Dynamic Client Registration (DCR) and if it doesn’t, either have the client provide a way to specify pre-registered client ID, or have the MCP server act as the registering authority (although at that point you partially implement the AS in your MCP server, at least for the /register endpoint).