The human authority boundary begins with responsibility rather than with a requirement to place a person somewhere in a diagram. It names the decisions and commitments that an organization reserves for authorized people because they involve purpose, contested values, material consequence, professional judgment, relationship stewardship, policy, or accountability. It also identifies decisions delegated to people in specific roles and the conditions under which a machine may prepare evidence or execute a bounded action. The line can differ by consequence: a system may classify a routine receipt under policy while finance retains a disputed liability decision, or draft a customer option while an authorized commercial leader retains the commitment.
A functioning boundary gives the person meaningful control. The decision packet must show the objective, source evidence, uncertainty, alternatives, affected parties, cost or consequence, machine actions already taken, missing information, and recovery options. The reviewer needs time and competence appropriate to the decision and must be able to request different evidence, reject the framing, refuse the action, escalate, or redefine the question. A nominal approve button after an opaque recommendation is not human authority. Nor is a review queue so overloaded that approval becomes the only practical way to keep work moving.
The boundary extends before and after the decision. People establish the goal, policy, data purpose, credentials, action limits, and stop conditions; they review outcomes, investigate incidents, hear challenges from affected parties, and change or withdraw the delegation. Some standing policies can authorize low-consequence machine actions without case-by-case approval, but accountable humans still own the policy, monitoring, exceptions, and correction. Authority should expire or be reverified when roles, sources, packages, systems, laws, risks, or organizational conditions change. Delegating to another agent or tool never converts human accountability into machine authority.