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[...]

AI Writes Code. Engineers Build Software.

With Claude Code and similar tools, I do not write much code by hand anymore. The AI does it for me. And most of the time, the result is good. For a moment this looks like the end[...]

Why in Spec-Driven Development the Spec Must Be Readable for All Stakeholders

In Spec-Driven Development (SDD), the specification is at the center. It is not just a document for developers or architects. It is the shared foundation for everyone who works on[...]