InvoiceValidationAgent and PaymentApprovalAgent: One blueprint and one agent identity per agent role; VendorNegotiationAgent: An independent blueprint, one agent identity, and one agent user account.

Invoice validation and payment approval are distinct finance roles with different ERP permissions, so each should have its own logical agent identity for least-privilege access and audit attribution. They can remain within the same finance trust boundary while using separate identities. The vendor-negotiation agent operates across an external supplier boundary and should therefore use an independent blueprint/trust boundary. Its dedicated Exchange Online mailbox introduces an additional Microsoft 365 requirement: Microsoft Entra Agent ID supports associating an agent identity with an agent user account when the agent needs resources that require a user object, such as Exchange mailboxes or Teams. Sharing a single identity across all roles would blur audit ownership and expand compromise impact. The answer therefore matches Microsoft ' s current agent-identity separation model. The same configuration should be paired with auditable identity, trace, and evaluation data so reviewers can prove which principal acted, which policy was applied, and why a request was allowed or blocked. That is particularly important for production multi-agent systems with external tools.

Official Microsoft reference: Microsoft Entra Agent ID - plan agent identity architecture

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The requirements ask for behavior that applies to every future conversation, improves routing for representative compound inputs, and standardizes final output with minimal application-code change. Few-shot instruction examples satisfy all three by demonstrating both the desired routing decision and the expected schema-compliant response for representative cases. Repository-wide constraints list rules but do not demonstrate how ambiguous compound requests should be handled. Per-request prompt cues are not durable across future conversations and would require application logic to inject them repeatedly. System role instructions define domains and objectives but provide less behavioral specificity than examples. Microsoft AI-500 prompt-engineering objectives explicitly include examples and dynamic prompt techniques for shaping complex agent behavior. Therefore C is the strongest design. The implementation should also preserve clear inputs and outputs around this step so that later agents receive only the information they require. This improves debuggability and keeps token, permission, and state growth under control as the workflow becomes more complex.

Official Microsoft reference: AI-500 Study Guide - advanced prompt engineering

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Separate managed identities for each agent and environment remove the need to store application secrets and create independent authorization boundaries. Assigning Azure roles at the resource level further limits each identity to only the Storage resource it requires. This sharply reduces lateral movement compared with a shared application principal or subscription-wide role. Microsoft Foundry and Azure identity guidance consistently recommend identity-based authentication, distinct identities when permissions differ, and the narrowest practical RBAC scope. In current Foundry deployments, the exact identity object may be represented through Microsoft Entra agent identity or a federated managed identity relationship, but the architectural principle in the option is correct. Therefore the solution meets both stated goals and the answer is A, Yes. From a security and governance perspective, the control should be enforced at the narrowest platform boundary that can deterministically block or constrain the action. Relying only on prompt text is weaker because the model can still be induced to behave unexpectedly.

Official Microsoft reference: Microsoft Foundry agent identity

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