Phase 2: Control & Containment · ~60 minutes · Python (stdlib · propose-then-commit state machine with idempotency)

Human-in-the-Loop: Propose-Then-Commit

The 2026 consensus on HITL is specific.

Hiring signal: Can operate human-in-the-loop: propose-then-commit in production

Introduction

It is not "the agent asks, the user clicks Approve." It is propose-then-commit: the proposed action is persisted to a durable store with an idempotency key; surfaced to a reviewer with intent, data lineage, permissions touched, blast radius, and a rollback plan; committed only after positive acknowledgement; verified after execution to confirm the side effect actually happened. LangGraph's interrupt() plus PostgreSQL checkpointing, Microsoft Agent Framework's RequestInfoEvent, and Cloudflare's waitForApproval() all implement the same shape. The canonical failure mode is the rubber-stamp approval: "Approve?" is clicked without review. The documented mitigation is challenge-and-response with an explicit checklist.

Type: Learn Languages: Python (stdlib, propose-then-commit state machine with idempotency) Prerequisites: Phase 15 · 12 (Durable execution), Phase 15 · 14 (Tripwires) Time: ~60 minutes

Objective

Learning objectives

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Key terms in this lesson

Agent