Teams know agent tokens are truly least privilege when each token maps to one narrow workload, one data domain, and one clear revocation decision. If the same token can service several tasks, or if a human cannot explain why a scope is needed, the model is not least privilege in practice.
Why This Matters for Security Teams
least privilege for agent tokens is not a paperwork exercise. An agent token that can reach multiple tools, data sets, or execution paths is already broader than most teams intend, especially once the agent can chain actions without a human in the loop. That is why current guidance from the OWASP Agentic AI Top 10 and the NIST AI Risk Management Framework emphasizes runtime context, not just static scopes.
NHIMG research shows how quickly identity sprawl turns into exposure: in The 2025 State of NHIs and Secrets in Cybersecurity, Entro Security reported that 60% of NHIs are being overused, with the same NHI utilised by more than one application. That pattern is a warning sign for agents too, because overused tokens usually hide unclear ownership, unclear revocation, and unclear purpose. In practice, many security teams discover overprivileged agent tokens only after a workflow has already touched data it was never meant to access.
How It Works in Practice
Teams verify least privilege by testing the token against the actual task, not the declared role. The token should authenticate one workload identity, carry only the claims needed for one action, and expire quickly enough that reuse is not practical. For autonomous systems, that usually means short-lived, task-bound credentials, workload identity, and policy decisions made at request time rather than during provisioning.
That runtime model is consistent with the direction of least-privilege guidance in OWASP Non-Human Identity Top 10 and the trust assumptions in NIST SP 800-207 Zero Trust Architecture. In practice, security teams should ask four questions:
- Can the token complete exactly one narrow workflow and no adjacent workflow?
- Is the token bound to a workload identity, such as SPIFFE or an OIDC-based workload token, rather than a shared secret?
- Does the authorization engine evaluate purpose, data domain, and runtime context before every sensitive call?
- Is revocation automatic when the task ends, fails, or changes scope?
For agentic systems, the token is only least privilege if it cannot be reused to pivot into another tool, another tenant, or another data set. NHIMG has documented how exposed and reused secrets accelerate real-world compromise in its Guide to the Secret Sprawl Challenge, which is directly relevant here because broad agent tokens behave like any other high-value secret once they escape the intended control boundary. These controls tend to break down in multi-agent pipelines with shared tool brokers because one token often starts serving orchestration, retrieval, and execution at the same time.
Common Variations and Edge Cases
Tighter token scoping often increases operational overhead, requiring organisations to balance reduced blast radius against more frequent issuance, debugging, and policy maintenance. That tradeoff is real, and current guidance suggests there is no universal standard for exactly how narrow an agent token should be across every workload.
Some environments make least privilege harder to prove. A retrieval agent may need temporary access to multiple indexes, but that does not justify a token that can write back to those stores. A code agent may need repository access, but not release permissions. A multi-agent planner may need delegated rights, but each sub-agent should still receive its own purpose-bound credential rather than inheriting a shared umbrella token.
Where teams usually get this wrong is confusing permission count with effective privilege. A token with only a few scopes can still be overprivileged if those scopes span unrelated systems or if the agent can chain them into a broader outcome. The better test is whether a human can explain why each claim exists, what it protects, and when it is revoked. NHIMG’s 2025 State of NHIs and Secrets in Cybersecurity and the OWASP NHI Top 10 both point to the same operational reality: least privilege fails when identities are shared, long-lived, or opaque.
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 AI RMF set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Non-Human Identity Top 10 | NHI-03 | Addresses overused and overly broad non-human identities. |
| OWASP Agentic AI Top 10 | A-05 | Focuses on agent permission boundaries and runtime misuse. |
| NIST AI RMF | Supports governing autonomous AI behaviour and accountability. |
Use AI RMF governance to require ownership, context checks, and revocation for agent tokens.
