Copilot Studio and Microsoft Foundry are not competitors — they sit at different levels of abstraction, and three changes in 2026 have quietly retired most of the advice written about choosing between them. A decision framework built on who owns the runtime, where the data already lives, and who operates the agent on day ninety, with the cost shapes, governance asymmetries and interop paths verified against Microsoft's own documentation.
A research-grounded enterprise reference architecture for autonomous AI agents: agent identity, task-bound authorization, tool and MCP gateways, memory security, runtime containment, observability, and incident response — with an OWASP agentic Top 10 mapping, a bounded-autonomy model, and a 38-control matrix.
AI services are entering organizations through every door at once. Treating them as enterprise platforms — with identity, data boundaries, logging, and governance — is the difference between adoption and exposure.
Microsoft's AI portfolio is not five versions of the same product — it is a layered enterprise architecture with an experience layer, two build platforms, a control plane, and the identity, data and threat controls underneath. A practical architecture guide to what each platform is for, which workloads belong where, how agent identity and authority actually flow, and what has to be true before an organization scales any of it.