A delegated access model in which an AI agent uses a limited slice of a human user's permissions rather than the user's full entitlement set. This concept matters because current IAM systems are better at assigning rights to people or services than to partial, task-bound proxies.
What Sub-User Access Means
Sub-user access describes a delegated access pattern where an AI agent operates with a narrower slice of a human user’s permissions instead of inheriting the full entitlement set. It is a response to the mismatch between modern task delegation and IAM systems built around whole-user accounts.
Why It Exists in Modern Access Design
The core idea is permission scoping: the agent should receive only the rights required for a specific task, data set, or application action. That makes the delegation model closer to least privilege than to simple account sharing, and it helps separate human intent from machine execution.
This is especially relevant when a human user has broad access across email, documents, admin consoles, or business systems, but the agent only needs a bounded subset of those rights. A well-designed sub-user access model reduces the need to expose the user’s full account context to automation.
How It Differs From Related IAM Patterns
Sub-user access is not the same as giving an agent the user’s password, session, or full identity token. It is also different from service-account style access, where the system acts under its own identity rather than as a constrained proxy for a person.
It sits between human delegation and machine identity design: the human remains the source of authority, but the agent receives a limited operational envelope. That distinction matters because access decisions, auditability, and revocation all change when the proxy is partial rather than complete.
Where Sub-User Access Breaks Down
The model becomes fragile when entitlement boundaries are vague, when applications cannot express partial delegation cleanly, or when the proxy inherits permissions that are broader than the task requires. It also creates governance complexity if the delegated slice is hard to review, explain, or revoke independently of the parent user.
In practice, the hardest problems are mapping real-world tasks to granular permissions and making sure the delegated scope does not silently expand through role inheritance, shared groups, or broad OAuth consent. IAM and IGA Basics is a useful reference point for understanding how entitlement models, access review, and least privilege shape that boundary.
How Practitioners Should Think About It
Sub-user access is best treated as an access-design problem, not just a product feature. The practical question is whether the delegated proxy can be constrained, observed, and revoked with enough precision to make partial authority safer than full-user exposure.
That is why access review, entitlement scoping, and workload-oriented identity patterns matter here. Access Reviews and Certification Guide helps frame how delegated permissions should be validated, while Cloud Workload Identity Guide is relevant when the proxy behaves more like a controlled workload than a human session.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP API Security Top 10 addresses the attack and risk surface, while NIST SP 800-53 Rev 5 sets the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | IA-2 — Identification and Authentication (Organizational Users) | Sub-user access inherits human authority and needs controlled authentication boundaries. |
| AC-6 — Least Privilege | The concept is a partial-permissions model built to reduce overexposure. | |
| IA-5 — Authenticator Management | Delegated access depends on managing credentials and tokens that enable the proxy. | |
| Recommendation — Bind delegated actions to authenticated users and enforce scope limits on the proxy. Grant only the minimum permissions needed for the delegated task. Use short-lived, tightly managed authenticators for delegated access paths. | ||
| OWASP API Security Top 10 | API5 — Broken Function Level Authorization | Partial delegation must still prevent agents from invoking functions beyond their scope. |
| API1 — Broken Object Level Authorization | Scoped proxies still need object-level checks for the records and resources they touch. | |
| Recommendation — Verify function-level authorization so delegated agents cannot call out-of-scope actions. Enforce object-level authorization on every delegated request. | ||
Related resources from NHI Mgmt Group
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Reviewed and updated by the NHIMG editorial team on October 7, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org