16th Edition · Three new chapters: the iteration context · reward hacking · blast radius

Your loop reported SUCCESS.
It was wrong by 132.

It didn’t crash. It didn’t warn anyone. It did exactly what you built it to do: keep going. Loop Engineering 101 is the practical guide to closing the gap between a loop that keeps going and a loop you can trust — from your first automation to the graph harness one rung above it. Now with the context an iteration deserves, the gate the agent cannot touch, and the blast radius you set before you choose the task.

Get the book — 20% off inside ↓ See what’s new

For founders, architects & engineering leaders already running agents.

compare.py — same task · same seed · only the structure changes
Watch the 60-second trailer

One flaky tool. Two answers.

Same task · same seed · only the structure changes · Watch on YouTube
Why this book — the four walls

Every loop hits the same four walls. No model moves them.

WALL 01 / 04

The plan lives in a window that rots.

Remembering is a wish, not a dependency.

→ filled by explicit dependencies
What’s inside

The whole discipline, from first trigger to graph harness.

31
chapters across six parts — from “do you actually need a loop?” to what comes after one, with three new chapters on context, reward hacking, and isolation.
90
lines of runnable code that put a naive loop and a graph harness on the same flaky task — and watch them land on 747 and 615.
4×4
the walls and their fixes — explicit dependencies, bounded recovery, an immutable log, a verifier gate.
20
lines of bash for the simplest working loop — plus the braked version with heartbeat, circuit breaker, budget ceiling, and a structured event log.
3
layers against reward hacking — a prompt, a deterministic gate on the test diff, and a judge on a different model. The agent breaks the test before it breaks the bug.
∞→□
the honest brake — including who shouldn’t build any of this yet, and the four ways loops quietly die — each one now with its signature in the log.
“The loop taught your agent to keep going. Everything after the loop exists so that you, not the loop, get to decide what counts.”
— Loop Engineering 101, Chapter 30
Get your copy

One book. Every wall named, every fix runnable.

Instant download, DRM-free, yours forever. Written for people who already run agents and are starting to feel the limits — every claim measured, every line of code runnable, every chapter honest about when not to build.

  • 16th Edition — three new chapters: The Iteration Context, Reward Hacking and the Gate the Agent Cannot Touch, and Isolation and Blast Radius
  • All the reference pages — the Loop Charter, the Build Order in ten steps, the four deaths, the pre-flight checklist
  • Runnable code — the 20-line loop, the braked loop, the context builder, the reward-hacking gate, the loop-vs-graph experiment
  • Free updates — every future edition included, no re-purchase
  • Read anywhere — polished, illustrated, print-quality layout
Loop Engineering 101 · 16th Edition
$99.99 $99.99
One-time payment · instant delivery
Secure checkout via Stripe · Instant delivery