Authority expansion breaks least privilege and weakens accountability. A user may start a task with limited scope, but a downstream agent or service account can quietly gain broader access than the original intent allowed. That creates a boundary violation even when each component technically authenticates correctly. The result is overexposure, harder investigations, and workflows that can act beyond business purpose.
Why authority expansion breaks the control boundary
Authority expansion across multiple AI agents and tools is not just a scaling problem. It changes the security boundary itself. Once one agent can invoke another, call tools, or inherit a delegated service identity, the effective privilege set can grow beyond the original user intent. That is where least privilege stops being a design principle and becomes a chain of trust problem. The OWASP Top 10 for Agentic Applications 2026 is useful here because it treats agentic misuse, excessive autonomy, and unsafe delegation as first-class application risks rather than edge cases.
What teams often miss is that each component can look correct in isolation while the overall workflow becomes over-authorised in practice. A user may be entitled to initiate the task, an agent may be entitled to plan it, and a tool may be entitled to execute it, yet the combined path still exceeds business purpose. That mismatch creates accountability gaps, because logs may show valid authentication at every hop while obscuring who actually authorised the most sensitive action. In practice, many security teams encounter this only after a downstream agent has already been trusted to do more than the original requester could have done directly.
How multi-agent authority creep shows up in real workflows
Authority creep usually appears when an orchestrator, agent, or tool chain starts to reuse trust rather than revalidate it. The first break is often identity delegation: a narrow user action is converted into a broader machine action through a shared session, long-lived token, or service account. The second break is scope translation: the system treats “help with the task” as permission to read, write, retrieve, or trigger far more than the task strictly needs. The third break is visibility. By the time a sensitive action occurs, the request path has passed through several components, each of which can truthfully say it was only executing its role.
That is why controls need to be evaluated at the point where authority changes hands, not only where the final action lands. Teams should distinguish between prompt-level intent, orchestration permission, tool permission, and data permission. When those layers are collapsed, a single successful authentication event can mask a much larger authorisation failure. NIST’s AI risk guidance is relevant here because it pushes organisations to manage AI systems as socio-technical systems with traceable risk, not as isolated prompts or model calls. The practical question is whether every hop can justify why it needs the authority it has, not merely whether it is technically allowed to proceed.
- Keep the user request, agent plan, and tool execution separately scoped.
- Issue the minimum identity or token needed for the specific step, not the whole workflow.
- Log the authority changes, not just the final action.
- Treat cross-agent delegation as a new trust decision, not a routing detail.
Where this guidance breaks down is in highly dynamic agent ecosystems where tool choice, sequence, or data source cannot be predicted in advance.
Where the edge cases and trade-offs become visible
Tighter delegation often reduces agent flexibility, so organisations must balance automation speed against authority containment. That trade-off becomes visible in workflows that span multiple domains, such as retrieval, ticketing, approval, and execution, because each step may require a different permission model. The harder the task is to pre-script, the more tempting it is to grant broad standing access so the workflow “just works.” That is usually where authority expansion becomes invisible until it is abused or audited.
There is also a genuine consensus gap in the industry about how much autonomy an agent should retain after it receives delegated access. Some teams prefer strict step-up approval before each sensitive tool call. Others tolerate broader delegation for efficiency but compensate with stronger post-action review. Both approaches can be defensible, but only if the organisation can explain what prevents one agent from becoming a proxy for the whole environment. The common failure is to assume that authenticated components equal authorised outcomes. They do not. A valid login path does not prove that the resulting access still matches the business purpose.
Teams should also be cautious with chained tool use, where one agent’s output becomes another agent’s input. That pattern can quietly amplify privilege if the second system trusts the first as an authority source. The control question is not whether each agent is allowed to operate. It is whether the chain preserves the original intent, scope, and accountability all the way through.
Risk and Threat Considerations
Authority expansion creates overprivilege, trust propagation, and accountability loss across agentic workflows. The material risk is not only excessive access, but also the ease with which a trusted agent or delegated service identity can move beyond the user’s original intent without tripping obvious authentication failures.
Failure mechanism: Delegated tokens, shared service identities, broad tool scopes, and chained agent handoffs let one component inherit or amplify authority that was never meant to travel with the task. Adversaries and abusive users can exploit that trust path by steering an agent into actions that are technically permitted for the workflow but not justified by the initiating request.
Impact: Sensitive data exposure, unauthorised actions, harder incident reconstruction, and broken accountability boundaries. Once authority is distributed across several agents and tools, it becomes difficult to prove which entity truly authorised the high-impact step.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
OWASP Agentic AI Top 10 address the attack surface, NIST AI RMF, CIS Controls v8 and NIST CSF 2.0 set the technical controls, and ISO/IEC 42001:2023 define the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| OWASP Agentic AI Top 10 | A1 — Excessive Agency | Covers agent workflows gaining more authority than intended. |
| Recommendation — Constrain agent authority so each step can only act within the narrow task scope. | ||
| NIST AI RMF | MAP — Measure, Analyze, and Manage | Fits governance of AI risk across chained agent decisions and delegations. |
| Recommendation — Map delegated agent authority paths and manage scope changes as AI risk events. | ||
| ISO/IEC 42001:2023 | A.6 — AI system lifecycle | Applies to governance of AI system behaviour across deployment and operation. |
| Recommendation — Control AI lifecycle changes that expand authority across orchestrated workflows. | ||
| CIS Controls v8 | 6 — Access Control Management | Directly addresses restricting and reviewing access paths in multi-agent tool use. |
| Recommendation — Enforce least privilege and remove unnecessary access paths from agent toolchains. | ||
| NIST CSF 2.0 | PR.AC-4 — Access Permissions Management | Maps to managing permissions so authorisation matches intended task scope. |
| Recommendation — Review and restrict permissions so delegated access stays aligned to business need. | ||
Practitioner Guidance
What to prioritise: Define the authority boundary at the workflow level, not just at the model or tool level. The most important check is whether any step can perform actions that the initiating user could not reasonably justify for that task.
What to verify: Confirm that delegated access is step-specific, time-bounded, and revocable, and that the audit trail preserves the handoff between user intent, agent decision, and tool execution. If those three cannot be reconstructed separately, the design is too permissive.
Common mistake: Treating “the agent is authenticated” as sufficient proof that the workflow is authorised. Authentication proves identity; it does not prove the workflow still matches purpose or scope.
Practitioner takeaway: The safest multi-agent design is the one that makes authority shrink, not accumulate, as work passes between components.
