Enterprise architects: your overdue Entra decision is an agent CSA schema

If you are an enterprise architect working on Microsoft Entra and AI agents, your first overdue job is not another policy wizard, another dashboard, or another governance steering committee. It is schema design. Specifically, it is deciding how you classify non-human identities with custom security attributes in Microsoft Entra . Not eventually. Up front. I keep seeing the same pattern across customers of every size: teams move quickly on agent experimentation, they onboard identities, they test controls, and then they realize they have no consistent attribute language for policy scope. At that point, every policy becomes a naming convention problem in disguise. That is backwards. The control plane starts with classification Custom security attributes are not decorative metadata. They are tenant-scoped key-value classifications you can assign to users, enterprise applications (service principals), and agent identities that are modeled as a service principal subtype, with dedicated role and permission boundaries for who can define and assign them ( overview , Graph model , agent identity service principal model ). That alone should change how architects think about them. This is not "nice to have taxonomy." This is policy input. Microsoft Entra Conditional Access for agents supports attribute-driven targeting with custom security attributes, and policy evaluation happens during token issuance and refresh, not just at policy authoring time ( Conditional Access for agents ). In other words: if your classification is sloppy, your runtime decisions are sloppy. Why agents raise the stakes You can say "an agent identity is still a service principal" and be technically correct. Microsoft Entra Agent ID is built on service principal infrastructure ( agent identities, service principals, and applications ). You can also miss the point. Agent identity introduces a blueprint-centered model where one blueprint can represent many agents, where blueprint-level policy decisions can