Delegated access is usually safer when the human’s own permissions are tightly scoped, because it preserves accountability and keeps the agent inside an existing governance model. Separate agent credentials can work, but only if the organisation can govern them with the same rigour as any other privileged non-human identity.
Why delegated access is the safer default when the human account is already well scoped
delegated access is usually the cleaner model because the agent inherits only what the human can already do, which preserves accountability and keeps approvals, audit trails, and exception handling inside an existing control structure. That matters most when the workflow is actioning user-specific tasks rather than operating as an independent system.
When a team treats delegation as the default, the key design question becomes whether the human principal is genuinely least-privileged. If the person already has broad entitlements, delegation simply passes that excess onward. The safer pattern is to narrow the human role first, then let the agent act only within that bounded scope, using established token exchange or on-behalf-of mechanics such as RFC 8693: OAuth 2.0 Token Exchange.
For agent governance, the important distinction is not “human versus machine” in the abstract, but whether the agent is borrowing authority or holding its own. NHIMG’s Agentic AI Identity Guide frames that boundary clearly: delegated authority, registration, and lifecycle controls are easier to reason about than a free-standing credential set that must be managed like a separate privileged actor.
When separate agent credentials are justified
Separate agent credentials can be the right answer when the agent needs stable service-like access, must run without an interactive human present, or must integrate with systems that do not support clean delegation. In those cases, the organisation is effectively creating a non-human identity, so the credential must be designed as a governed asset, not a convenience token.
The trade-off is simple: separate credentials can improve operational continuity, but they also expand blast radius if they are overprivileged, long-lived, or reused across environments. That is why controls around scoping, rotation, expiry, and inventory are not optional. NHIMG’s API Key Management Guide is useful here because the same lifecycle discipline applies to any agent credential that can be used repeatedly or remotely.
Where separate credentials are unavoidable, teams should treat them as first-class identities with ownership, offboarding, and monitoring. If the organisation cannot answer who owns the credential, how it is revoked, and how abnormal use is detected, the design is not mature enough for production. The risk is not the existence of a machine credential, but the absence of the same governance that would be demanded for a privileged human account.
How to choose between the two models in practice
The practical decision rule is: use delegated access when the agent is acting on behalf of a specific user and the user’s scope is already constrained; use separate credentials when the agent needs autonomous service continuity, but only with explicit ownership and privilege boundaries. That choice should be made per workflow, not as a one-time architectural slogan.
Many teams underestimate how quickly “separate credentials” become hard to govern at scale. Once multiple agents, environments, and toolchains are involved, credential sprawl, renewal failures, and ambiguous ownership become the real failure modes. A good design makes the agent’s authority visible in logs, reviewable in inventory, and revocable without breaking unrelated human access. NHIMG’s Secrets Management Guide is a strong reference point for that operational discipline.
If the organisation is unsure, start with delegation and only move to separate credentials when a concrete technical constraint or availability requirement forces the issue. Separate credentials should be the exception that earns its place through control maturity, not the default because they are easier to wire up.
Risk and Threat Considerations
Separate agent credentials enlarge the compromise surface because any leaked token, overbroad scope, or shared secret can be reused without the human’s involvement. Delegated access usually limits that exposure better, but only if the human account itself is well protected and its privileges are genuinely narrow.
Failure mechanism: Weak scoping, long-lived secrets, or credential reuse turns an agent into an easy persistence path. If the agent can act independently, an attacker who captures its credential often inherits durable access and may bypass the normal human approval path entirely.
Impact: The result can be unauthorized actions, hard-to-attribute changes, and broader blast radius than the originating human account would have allowed. In a distributed environment, the damage is often operational first, then forensic, because the control failure shows up as “normal” authorised activity until the scope of the credential is examined.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Non-Human Identity Top 10 and OWASP Agentic AI Top 10 address 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 |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-04 — Insecure Authentication | Delegation vs separate agent credentials is fundamentally about how non-human access is authenticated. |
| NHI-05 — Overprivileged NHI | The choice hinges on preventing agents from inheriting or holding excessive permissions. | |
| NHI-07 — Long-Lived Secrets | Separate agent credentials create lifecycle and rotation risk when they persist beyond a task. | |
| Recommendation — Prefer bounded delegated flows and avoid standalone agent credentials where authentication can be inherited safely. Scope agent access to the minimum permissions needed and review privilege regularly. Use short-lived credentials and enforce rotation or expiry for any agent-held secret. | ||
| OWASP Agentic AI Top 10 | ASI03 — Identity & Privilege Abuse | Agent authority can be abused when delegation or standalone credentials exceed intended scope. |
| Recommendation — Constrain agent authority and validate that every privileged action is explicitly authorised. | ||
| NIST SP 800-53 Rev 5 | IA-5 — Authenticator Management | Separate credentials require lifecycle control over issuance, rotation, and revocation. |
| Recommendation — Manage agent authenticators with defined issuance, expiry, rotation, and revocation processes. | ||
Practitioner Guidance
What to verify: Confirm whether the workflow truly requires autonomous machine authority, or whether on-behalf-of delegation already satisfies the use case. If the answer is delegation, verify that the human principal is least-privileged before you let the agent inherit access.
What to prioritise: For separate agent credentials, prioritise ownership, expiry, revocation, and monitoring over convenience. A credential that cannot be confidently rotated or traced should not be treated as production-safe.
Practitioner takeaway: Default to delegated access when you can, because it keeps the agent inside an accountable identity boundary; move to separate credentials only when you can govern the agent as rigorously as any other privileged identity.
Related resources from NHI Mgmt Group
- Why do organisations use SSO for privileged access tools and vaults instead of separate credentials?
- How can organisations reduce the blast radius of compromised agent identities?
- How do organisations reduce the dwell time of exposed credentials at scale?
- How should organisations stop auto-sync from turning desktops into repositories of credentials?