gatekeeper agent

A critic advises and can be overridden. A gatekeeper decides flow and cannot. A critic raises blockers; the gatekeeper asks whether those blockers were closed before the run moves on.

The second boundary is sharper: a gatekeeper governs flow, not preference. Its scope is "can this proceed?", kept apart from "would the operator want this?" Gate the flow, not the judgment makes that separation the design's core rule and enforces it by absence. The gatekeeper is spawned headless, forbidden from loading the main framework context, and reads only a staged per-checkpoint directory: the artifact, a bounded log slice, the state file, the conventions doc, and its own persona file. It cannot model what you would have wanted because nobody staged those inputs in.

What it emits

The verdict is a fixed record, not prose: Decision (proceed, revise, or escalate), Artifact-hash, Uncertainties, a one- or two-sentence Rationale, Required-changes tagged by root cause, an Escalation reason or none, and a Ledger-pointer.

Escalation is defined rather than left to taste. It fires when a critic's blocker fix looks thin or wrong, when a scope decision materially changes cost or timeline, when two valid approaches are a real tradeoff, when the work touches a production database, billing, auth, secrets, or access, or when a blocker stays unresolved or the revision cap of two is exhausted. And it fires when the orchestrator's path is spec-compliant but violates doctrine.

The default failure direction is fixed. A missing or timed-out verdict escalates. It never auto-proceeds.

The same role under another name

Who checks the checker is the build log behind that design, where the role is called the delegate: an agent above the orchestrator that takes routine approvals and escalates the real product calls. On one run it caught twenty build-breaking defects across three rounds that the cold critic had already passed clean.

That essay also names the obvious next question. An automated approver can rubber-stamp, so a gate is only real if something outside the gated party can check it. In the Bureau that outside check is the Notary, which gets a sealed packet and blind-samples the gatekeeper's proceed verdicts against the real artifacts.