Use a user identity when a person is signing in and should act in their own context; use a workload identity for software acting as a service. For autonomous or semi-autonomous AI agents, Microsoft Entra Agent ID offers a separate, agent-specific model where supported. Don’t use a person’s account as a convenient substitute for a service identity.
What each identity represents
The decision starts with the actor. A user identity represents a person. A workload identity represents software—such as an application, service, script, or container—that authenticates to access services or resources. Microsoft Entra workload identities include applications, service principals, and managed identities. Microsoft’s workload-identity overview, updated May 8, 2026, also describes agent identities as a distinct case. Microsoft Learn: Workload identities
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An agent identity is a special kind of service principal, but it is not simply an ordinary application service principal with an AI label. Microsoft’s agent model separates the identity representing the agent from the blueprint that holds credentials and obtains tokens on the agent identity’s behalf. Microsoft Learn: Agent identities, service principals, and applications
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How the three choices differ
| Identity | Represents and typical use | Authentication and permissions | Oversight and main consideration |
|---|---|---|---|
| User identity | A person signing in or directing an interactive action. | Uses human sign-in methods and user policies; access is assigned to and governed in the person’s context. | Manage through user lifecycle and access governance. It is not a good substitute for a service identity. |
| Workload identity / standard service principal | An application or other software workload, typically for deterministic services or automation. | Uses a workload credential, managed identity, or federation, depending on the design. Permissions are assigned to the workload principal. | The workload owner must manage credentials, permissions, and lifecycle; unmanaged credentials can be difficult to govern. |
| Microsoft Entra agent identity | An AI agent requiring an identity and governance specific to that agent. | The agent identity holds permissions and appears as the acting identity; its associated blueprint holds credentials and obtains tokens on its behalf. Some permissions can be inherited from the blueprint. | Supports agent-specific sponsorship, lifecycle governance, and audit attribution. A blueprint’s credentials create a shared security boundary for the agent identities associated with it. |
This comparison summarizes Microsoft’s documentation on workload identities, agent identity architecture, and agent governance. Actual support and configuration depend on the tenant, hosting platform, and product integration. Workload identities · Agent identity architecture · Governing Agent Identities
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For an agent, distinguish actor, credential holder, and permission holder
These are related but separate architecture questions: which identity is shown as the actor, which principal holds the credential used to obtain a token, and which principal receives permissions? In the documented Agent ID model, the agent identity represents the agent and holds its permissions, while the blueprint supplies credentials and acquires tokens on its behalf. One blueprint can support multiple agent identities, so blueprint membership also defines a credential and compromise boundary. Microsoft Learn: Agent identity architecture
Where agent credentials live
Agent identities do not hold credentials themselves. Microsoft lists federated identity credentials, certificates or cryptographic keys, and client secrets as blueprint credential types. For agents hosted in Azure, a managed identity can serve as a blueprint credential; that does not replace the agent identity. The platform’s current integration and tenant prerequisites determine whether this model is usable in a particular deployment. Microsoft Learn: Overview of agent identities
Rank #2
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Why a shared blueprint deserves scrutiny
Sharing a blueprint can make common credential and control management possible, but it also means a blueprint credential compromise may affect the agent identities associated with it. Decide which agents belong together based on their trust, ownership, and access needs rather than treating one blueprint as a neutral default. Microsoft describes blueprint-level controls and governance for agent identities. Microsoft Learn: Agent identity architecture · Microsoft Learn: Governing Agent Identities
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Choose the identity that matches the action
A person is interacting and should act as themselves
Use the person’s user identity when the action is initiated interactively and should be performed in that person’s context. Apply the relevant user and access controls rather than giving the agent a shared human login.
Rank #3
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- WORKS WITH 1000+ ACCOUNTS: Compatible with popular accounts like Google, Microsoft, and Apple. A single YubiKey 5 NFC secures 100+ of your favorite accounts, including email, password managers, and more
- FAST & CONVENIENT LOGIN: Plug in your YubiKey 5 NFC via USB and tap it, or tap it against your phone (NFC), to authenticate. No batteries, no internet connection, and no extra fees required
- MOST SECURE PASSKEY: Supports FIDO2/WebAuthn, FIDO U2F, Yubico OTP, OATH-TOTP/HOTP, Smart card (PIV), and OpenPGP. That means it’s versatile, working almost anywhere you need it
- PRIMARY & SPARE KEYS: Just like having a spare house key, we recommend buying two YubiKeys - one for daily use and one as a spare. That way you’ll never get locked out of your accounts
A deterministic service or automation needs access
Use an appropriate workload identity. Prefer a managed identity when the hosting environment supports it; otherwise assess a service principal with suitable credential controls or workload identity federation for a supported external workload scenario. Microsoft’s workload-identity overview describes these patterns. Microsoft Learn: Workload identities
An autonomous or semi-autonomous AI agent needs its own governance
Assess Microsoft Entra Agent ID if the deployment platform supports it and its agent-specific identity, sponsor, lifecycle, permission, and audit features fit the requirements. Do not assume every agent platform supports this model, or that an ordinary service principal provides the same agent-specific governance. Microsoft Learn: Overview of agent identities · Microsoft Learn: Microsoft Entra security for AI
Rank #4
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- WORKS WITH 1000+ ACCOUNTS: Compatible with Google, Microsoft, and Apple. A single Security Key NFC secures 100 of your favorite accounts, including email, password managers, and more.
- FAST & CONVENIENT LOGIN: Plug in your Security Key NFC via USB-A and tap it, or tap it against your phone (NFC) to authenticate. No batteries, no internet connection, and no extra fees required.
- TRUSTED PASSKEY TECHNOLOGY: Uses the latest passkey standards (FIDO2/WebAuthn & FIDO U2F) but does not support One-Time Passwords. For complex needs, check out the YubiKey 5 Series.
- BUILT TO LAST: Made from tough, waterproof, and crush-resistant materials. Manufactured in Sweden and programmed in the USA with the highest security standards.
Governance and audit implications
Assign human accountability
Microsoft’s agent governance documentation describes assigning a human sponsor accountable for the agent’s purpose, lifecycle decisions, and access. It also describes lifecycle management, access reviews, permissions, Conditional Access, and agent discovery or inventory capabilities. Check current availability and licensing for the tenant and deployment before relying on any of these capabilities. Microsoft Learn: Governing Agent Identities · Microsoft Learn: Microsoft Entra ID Governance overview
Keep the acting identity visible in logs
Microsoft says audit and sign-in records can show the agent identity as the acting client while also indicating its relationship to the blueprint. This helps distinguish the identity that acted from the source of the credential used to obtain its token. Microsoft Learn: Agent identity architecture
Best Value
- The information below is per-pack only
- POWERFUL SECURITY KEY: The Security Key C NFC is the essential physical passkey for protecting your digital life from phishing attacks. It ensures only you can access your accounts.
- WORKS WITH 1000+ ACCOUNTS: Compatible with Google, Microsoft, and Apple. A single Security Key C NFC secures 100 of your favorite accounts, including email, password managers, and more.
- FAST & CONVENIENT LOGIN: Plug in your Security Key C NFC via USB-C and tap it, or tap it against your phone (NFC) to authenticate. No batteries, no internet connection, and no extra fees required.
- TRUSTED PASSKEY TECHNOLOGY: Uses the latest passkey standards (FIDO2/WebAuthn & FIDO U2F) but does not support One-Time Passwords. For complex needs, check out the YubiKey 5 Series.
Do not turn a user into a service account
Microsoft explicitly does not recommend user accounts as service accounts because they are less secure. A non-human process should have an identity designed for a workload or, where supported and appropriate, an agent-specific identity. Microsoft Learn: Governing Microsoft Entra service accounts
Quick Recap
Questions to settle before deployment
- Actor: Is the operation performed by a person, deterministic software, or an autonomous or semi-autonomous agent?
- Credential custody: Which principal holds the credential, and how is it protected and rotated or otherwise governed?
- Permissions: Which identity receives access, and can the scope be limited to the resources and actions needed?
- Ownership: Who owns the workload or sponsors the agent, and who makes lifecycle and access decisions?
- Blueprint boundary: If using Agent ID, which agents share a blueprint and its credential risk?
- Evidence and support: Does the platform integrate with the selected identity model, and do logs let operators identify the actor? Verify current feature availability and licensing against Microsoft’s governance documentation. Microsoft Learn: Governing Agent Identities
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