Harness Engineering: Why a Minimal CLAUDE.md and a Good Architecture Document Belong Together
The term Harness Engineering has established itself in recent months. The formula behind it is simple: Agent = Model + Harness. The harness is everything that makes up an AI[...]
Shift Left Needs Artifacts, Not Just Conversations
Rachel Laycock wrote a post called Maybe We Shouldn’t Be Reviewing All This Code. It is a response to Brian Houck, who worries that automating code review away will cost us[...]
The Three Levels of Spec-Driven Development, and Where the AI Unified Process Sits
Spec-driven development is a popular term at the moment. Everybody uses it, and everybody means something slightly different. Birgitta Böckeler from Thoughtworks wrote a helpful[...]
Code Is No Longer the Bottleneck. Requirements Are.
On August 21, 2026, Anthropic published The AI-Native SDLC Playbook. It is worth reading. It describes how the software development lifecycle changes when agents write most of[...]
A Paper from 1995 Describes How You Should Work with AI Agents
The paper is older than Java. And it answers a question everyone is asking in 2026: Who guards the architecture when AI agents write the code?
Modernizing Legacy Systems with the AI Unified Process
Most software modernization projects do not fail because of technology. They fail because nobody knows anymore what the old system actually does. The code is there. It runs. It[...]
Waterfall Was Never the Problem
Every time I talk about Spec-Driven Development, someone says the same thing. “That is just waterfall.” They mean it as a gotcha. It is not. Two things are going on[...]
Use-Case 3.0: The Refreshed Guide to Driving Development with Use Cases
Use cases have been around since 1987. In May 2024, Ivar Jacobson, Ian Spence, and Keith de Mendonca published a refreshed guide called Use-Case 3.0. If you read my earlier post[...]
AI Writes the Code. This Book Still Teaches the Use Cases.
In the AI Unified Process (AIUP), the spec sits at the center. The use case is the unit of work. You write a system use case, AI generates the code, and tests confirm the[...]
Shift-Left: Getting the Spec Right Before the Code
In software, “shift-left” means doing the important work earlier. The earlier you catch a problem, the cheaper it is to fix. We learned this with testing and later[...]
Bug or Enhancement? How the AI Unified Process Handles Change Requests
In a spec-driven world, every change to the running system has a reason. Either the system does something it should not do, or we want it to do something new. AIUP captures this[...]
What, Harness, How: The Three Layers of AIUP
One of the recurring questions I hear about Spec-Driven Development is this: where does the spec end and the implementation begin? The line is often blurry. Specs leak into class[...]
