Definitions and setup: Human-in-the-loop

Definitions

Human-in-the-loop, approval gate, escalation

Human-in-the-loop (HITL): a person takes part in the run, by approving, editing, answering a question or taking over.
Approval gate: a point where a risky action waits for a decision.
Escalation: handing a case to a person because the agent cannot or should not decide.

Irreversible action, blast radius, risk score

Irreversible action: one that cannot be undone, such as sending an email or moving money.
Blast radius: how much is affected if the action is wrong.
Risk score: the agent's or a rule's estimate of how likely harm is.

Approval fatigue, rubber-stamping

Approval fatigue: reviewers read less carefully as requests pile up.
Rubber-stamping: approving without reading, which makes the gate look safe and be unsafe.

Interrupt, resume, default-deny

Interrupt: stopping a run at a point and saving it to wait for input.
Resume: continuing from the saved state with the person's answer.
Default-deny: if no decision arrives, the action does not happen.

The shape of a gate

A gated step pauses and saves state, waits for a person, re-checks the premise and then executes with an idempotency key.

Five properties make it work: a risk rule that decides what to gate, a durable pause (module 7), a useful request (what, why, what changes, how to undo it, and the option to edit), a re-check on resume, and an idempotent execution (module 6).