Delegation Chains Need Expiry at Every Hop

Every delegation hop needs explicit scope, audience, purpose, and expiration bounded by its parent mandate.

Why this question matters

Agent workflows transform a single instruction into a chain of tasks. If downstream agents inherit a credential or an abstract statement of authority without a shorter lifetime, the final participant may retain power long after the user expected the job to end.

Expiry is not merely a token field. It should apply to the task purpose, permitted counterparties, data access, spending limits, and ability to delegate again. A child mandate must never outlive or exceed the authority from which it was derived.

Signals worth observing

• A child task remains active after its parent is cancelled or expires.
• Delegation depth grows without an explicit maximum.
• A downstream agent reuses authority for a different principal or purpose.

Practical control direction

1. Cap child expiry at the earliest parent deadline.
2. Carry delegation depth and purpose in verifiable task context.
3. Cascade revocation through every active descendant.

Sources and further reading

• NIST NCCoE: Software and AI agent identity and authorization
• Model Context Protocol authorization specification
• Google Cloud: Agent Payments Protocol

Next field note: Least Privilege Must Follow the Current Step