The Wall Has a Door: Build with AI

About the Book

This book is for experienced professionals who know the work better than the software does.

For most of the history of software, domain expertise and the ability to build software lived in different people. That gap produced a generation of tools built by people who understood the technology but not the problem, and a generation of experienced professionals who understood the problem but had no path to the solution. That gap has narrowed enough to change who gets to build.

In four months, starting with no coding background, no CS degree, and no technical cofounder, the author built three real software products across three different technology stacks: a retirement simulation platform with Monte Carlo modeling, a native iOS health analytics app, and a puzzle game published through Apple. Not by learning to code. By learning to direct, using AI as the executor and domain expertise, operational discipline, and judgment as the thing that made the direction worth following.

The Wall Has a Door is the complete methodology that came out of that experience: how to define what you're building before you touch a tool, how to write specs precise enough that AI can't drift from them, how to direct AI as an executor rather than a collaborator, how to catch failures before they become expensive, and how to supervise entire systems of AI agents working together. It is not about prompt tricks, and it is not a beginner's guide to AI tools. It is a system for people who have spent years developing exactly the skills this methodology requires, even if none of those years involved software.

The book contains an introduction and 25 chapters across four parts:

• Part 1: The Methodology — three products, every mistake, and how the methodology emerged from the failures
• Part 2: Working With AI — the day-to-day mechanics of directing AI without losing control of the work
• Part 3: Building an Agent System — moving from a single conversation to a supervised system of AI agents
• Part 4: What This Unlocks — the larger shift this represents, and your first concrete step

If you have managed projects, defined requirements, deployed systems, or spent years getting deeply good at something that has nothing to do with software, you already have the foundation. This book shows you how to build on it.

Content complete, approximately 51,000 words. A professional copy edit is currently underway; all buyers receive the polished edition free the moment it's ready, as with every Leanpub book.