I Actually Practice TDD Now (Thanks to AI Agents)

After 15+ years of advocating for test driven development without consistently doing it, coding agents finally made TDD my default workflow

Jan 28, 2026

3 min read

By Craig Sturgis

I actually practice what I preach now when it comes to test driven development.

I loved the idea of test driven development (TDD) from when I first heard about it somewhere between 15 and 20 years ago. Big advocate.

Did I ever do it? Not most of the time. I could never get over the setup hump and it felt more natural to just build. I've been doing that since I was 12.

Was that wise? not really, but it worked well enough for me.

It wasn't until I worked with Anthony Panozzo that I started to develop the habit - because he did the setup and showed the way. But that startup folded.

Seven years of product management later, I dove back into code. I went right back to my old build first habits.

Then I started working with coding agents. And today's best agents and models like Claude Code with Opus 4.5 are great at building the right test suites at every level - unit, integration, and end-to-end.

Now, I can have the agents do all the setup. I describe what I want to test and it just does it - iterating until it's green. I get the benefit of the coverage and the confidence to make more ambitious changes, without having to go through the drudgery of setting up the test code, the mocks and the fixtures myself.

I don't have to break my 30 years of build first habits, I just tell my agents to practice test driven development, and that's the default for every task.

An army of robots all with the mantra of red, green, refactor. It's a beautiful thing.