TDD, AI agents and coding with Kent Beck

The Pragmatic Engineer

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Kent Beck is one of the most influential figures in modern software development. Creator of Extreme Programming (XP), co-author of The Agile Manifesto, and a pioneer of Test-Driven Development (TDD), he’s shaped how teams write, test, and think about code.

Now, with over five decades of programming experience, Kent is still pushing boundaries—this time with AI coding tools. In this episode of Pragmatic Engineer, I sit down with him to talk about what’s changed, what hasn’t, and why he’s more excited than ever to code.

In our conversation, we cover:

• Why Kent calls AI tools an “unpredictable genie”—and how he’s using them

• Why Kent no longer has an emotional attachment to any specific programming language

• The backstory of The Agile Manifesto—and why Kent resisted the word “agile”

• An overview of XP (Extreme Programming) and how Grady Booch played a role in the name

• Tape-to-tape experiments in Kent’s childhood that laid the groundwork for TDD

• Kent’s time at Facebook and how he adapted to its culture and use of feature flags

• And much more!

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Timestamps

(00:00) Intro

(02:27) What Kent has been up to since writing Tidy First

(06:05) Why AI tools are making coding more fun for Kent and why he compares it to a genie

(13:41) Why Kent says languages don’t matter anymore

(16:56) Kent’s current project building a small talk server

(17:51) How Kent got involved with The Agile Manifesto

(23:46) Gergely’s time at JP Morgan, and why Kent didn’t like the word ‘agile’

(26:25) An overview of “extreme programming” (XP)

(35:41) Kent’s childhood tape-to-tape experiments that inspired TDD

(42:11) Kent’s response to Ousterhout’s criticism of TDD

(50:05) Why Kent still uses TDD with his AI stack

(54:26) How Facebook operated in 2011

(1:04:10) Facebook in 2011 vs. 2017

(1:12:24) Rapid fire round

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The Pragmatic Engineer deepdives relevant for this episode:

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See the transcript and other references from the episode at ⁠⁠https://newsletter.pragmaticengineer.com/podcast⁠⁠

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