You are designing Microsoft Foundry multi-agent solution.

A shared single-tenant application registration combined with subscription-wide role assignments creates an excessively broad trust and authorization boundary. It also does not, by itself, guarantee elimination of stored credentials because an app registration can still authenticate with a client secret or certificate unless federation is configured. More importantly, compromise of any agent using the shared identity could expose resources well beyond that agent ' s assigned Storage container. Microsoft guidance favors distinct workload/agent identities and the narrowest practical Azure RBAC scope, ideally at the resource or data-resource level required by each agent. Because the proposed design uses both a shared identity and subscription-level access, it fails the blast-radius requirement and least-privilege principle. Therefore B, No, is correct. Least privilege remains the governing principle: grant only the identity, data, tool, or deployment access required for the specific operation. The selected answer preserves that boundary while still allowing the workflow to satisfy its functional requirement.

Official Microsoft reference: Microsoft Foundry agent identity

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