Microsoft Dropped ACP for UCP in 104 Days. Identity Linking Is Why.

Microsoft switched from ACP to UCP in 104 days due to Identity Linking capability, which allows AI agents to recognize customer loyalty programs and member-only pricing. This capability is crucial for merchants to maintain customer relationships. To implement UCP, developers should add the Identity Linking capability declaration to their /.well-known/ucp profile. The flow uses standard OAuth 2.0 Authorization Code.