I remember he first posted 2+ years ago, back when people first realized ChatGPT might be useful for coding, that "90% of my skills are now worthless and the remaining 10% are worth 1000x"
I’m is the opinion that the test first XP style of development pays more dividends now than ever, simply because you can use it to validate the code that AI generates and importantly it makes it easier to generate code from these AI tools.
One of these "AI coding" things that come across as a code smell is the habit of littering outdated reports/guides in the repo. That seems to be happening here too.
This is clearly an AI-generated report based on the code at the time of the generation. I don't see the point of storing them in the history? Especially as this _updated_v2_from_2025 trail of debris.
I think that XP was the only true agile methodology. Agile just got more and more corrupted over the years through stupidity.
Clearly AI programming allows you to quickly close feedback loops. I don't think everything needs a comprehensive set of unit tests though.
But if people can go back and understand the core concept of XP (which again is about feedback loops to me) and take advantage of LLM-based agent systems to create those tight closed feedback loops, then that will be an advance for software engineering.
Starting with XP and in shops doing XP quite intensely has ruined me because I simply can't stomach working in "SCRUM" shops where a whole pile of stuff is taken as "agile" dogma which is mostly just ritualized meaningless bastardizations of things that XP pioneered, turned inside out.
I think the ideal scenario is usually two paired programmer using a shared set of AI agents on the same working branch together. It's an ideal feedback loop of paired planning, reviewing, building, and testing.
“Unit tests are small tests, each one exercising a little piece of functionality. The units tested are usually individual methods, but sometimes clusters of methods or even whole objects.”
Extreme Programming Explained: Embrace Change, 2nd Edition (2004) Kent Beck
I also wonder if this is written from a statically-typed perspective. In dynamic-typing land there are so many more stupid little things that can break that the compiler would otherwise catch for you
Either that or tracing/logging/debugging, but other than specific niches like parsing (of specific bug repros) I think integration tests are generally a lot more bang for the buck.
Anyway, if you want to go down a related-but-unrelated rabbit hole, J.R. Thompson's lecture on the Space Shuttle Main Engines is a good one. You can probably watch it at higher speed to smooth out the many, many "uh"s (believe me, it's bad):
I think a more accurate version of this is: unit tests were not only per-method but also per functionality. This was often called BDD (Behavior Driven Development), e.g. Ruby's cucumber. Your intuition here is correct though.
We're practically a 100% XP shop compiled of ex-Pivots and Thoughtworks. Pairing, TDD and client-on-site as our baseline. We've also been using AI as part of our IDEs full-time for 2+ years.
Yet, the most unexpected thing happened this year on my team of 4 senior/staff-level developers:
Instead of "splintering/pairing off with AI" individually even further, we wound up quadrupling (mobbing) full-time on our biggest project to date. That meant four developers, synchronously, plus Claude Code typing for us, working on one task at a time.
That was one of the most fun, laser-focused and weirdly effective way of combining our XP practice with people and AI.
Yeah, much of XP has just been integrated into modern workflows (for the better!), really getting this out there as a call to arms for folks to _think_ before they churn out 1000s of lines of code with an LLM and ship without thought!
From your perspective, which bits of XP would you consider weird?
Just in case: This is not a call for everyone to "pair program" with an AI.
If you pair program with someone else on your team, you both learn what the other is thinking. You both become more familiar with what the code is doing, and why it's doing it.
If you "pair program" with an AI, anything it learned, it forgets as soon as the prompt is closed.
So don't think that's what he's talking about here. He's talking about XP, with humans, just like in the 1990s. There may be some AI in there too, but that's not where the XP part comes from.
That's only if you don't preserve the results explicitly. If you're trying to delve into some new code without enough docs, I could imagine learning lots about the system along the LLM and then leaving that as documentation and/or agent files in the repo.
> Just in case: This is not a call for everyone to "pair program" with an AI.
If that's not what you're doing, you're likely doing it wrong.
> If you pair program with someone else on your team, you both learn what the other is thinking. You both become more familiar with what the code is doing, and why it's doing it.
Yes.
> If you "pair program" with an AI, anything it learned, it forgets as soon as the prompt is closed.
Same with humans, including your future self. So pair on docs.
TL;DR: You should absolutely be XP pair programming with your LLM.
Extreme Programming attempts to weave together several independently useful concepts into a single paradigm... For that to make sense, the amalgamation of ideas has to be greater than the sum of its parts individually, but it's not clear that this is the case.
TDD is useful in some situations, yep totally. Pair programming is useful in some situations, yes. Continuous integration; yes, much of the time. Frequent feedback; yes, sometimes, for some types of work which doesn't require deep focus...
It just doesn't work as a blanket 'XP' paradigm because you rarely need all these parts all the time, at the same time. IMO, this is why Extreme Programming lacks gumption as a concept. It feels like a bunch of good ideas thrown together. If there was some kind of synergy between those ideas and practices, the concept of XP would be more important.
As it stands today, everyone is implementing maybe 1 or 2 aspects of XP, but almost nobody is implementing ALL of XP... So nobody can claim that they're adhering to XP.
This is not the same as as 'Agile' because with Agile; the vast majority of big companies are implementing maybe 90% of agile practices, with 70% fidelity... This consistency is enough for companies to identify themselves as 'Agile'. I've worked for many companies which implemented ALL of the Agile practices but not one of them actually implemented them exactly as taught in the Agile Manifesto. I think the closest one I worked for was maybe 90% of the way there; they even followed the story point system exactly and used a packet of cards with numbers on them to allow people to vote during Sprint Planning meetings... but anyway, pretty much all the companies/projects I worked for identified themselves 'Agile' because all the practices fit into a single paradigm and there was value in adopting all of them. After a while, it became easier for project managers to just say "Let's switch to Agile" instead of saying "Let's time-box our development work into short increments, with a planning meeting, refinement meeting and retrospective meeting for each 2-week increment."
That's why the XP book arranges itself into values, principles, and practices. The best line in the book is about how practices without underlying values are dead, while values without practices are wishy-washy abstractions. What he's really advocating for at the highest level is skilled teams, who are given ownership, that are actively defining their own processes, and executing them with discipline to produce well-designed and reliable software. The book is a "grab bag" (very legitimate point) because those are the sorts of techniques that those kinds of teams use.
Agreed, we’ve come a long way since the dogmatic agile of the 90s, and maybe I could be more explicit that this is about introspecting how you’re delivering software (now AI-enabled workflows are everywhere) to decrease the probability of only increasing output (rather than increasing the probability of outcomes) for your users… XP is a good place to start (but not necessarily end).
>TDD is useful in some situations, yep totally. Pair programming is useful in some situations, yes. Continuous integration; yes, much of the time. Frequent feedback; yes, sometimes
For production code I do pretty much all of these, always - at least insofar as it is possible (e.g. willing pairing partner).
Im curious to know under which scenarios you think im doing something wrong. Coz I dont think i am.
What is Extreme Programming => XP is an agile methodology that keeps teams laser‑focused on delivering working software through short iterations, tight feedback loops, and simple design, using practices like pair programming, test‑driven development, and continuous integration to adapt quickly to changing needs. It optimizes for learning and quality over raw output: build the smallest thing, test it, ship it, and iterate with the customer.
~ GPT5 in perplexity
Readit News
https://tidyfirst.substack.com/p/augmented-coding-beyond-the...
I remember he first posted 2+ years ago, back when people first realized ChatGPT might be useful for coding, that "90% of my skills are now worthless and the remaining 10% are worth 1000x"
https://tidyfirst.substack.com/p/90-of-my-skills-are-now-wor...
This is clearly an AI-generated report based on the code at the time of the generation. I don't see the point of storing them in the history? Especially as this _updated_v2_from_2025 trail of debris.
https://github.com/KentBeck/BPlusTree3/blob/main/rust/docs/C...
https://github.com/KentBeck/BPlusTree3/blob/main/rust/docs/U...
Clearly AI programming allows you to quickly close feedback loops. I don't think everything needs a comprehensive set of unit tests though.
But if people can go back and understand the core concept of XP (which again is about feedback loops to me) and take advantage of LLM-based agent systems to create those tight closed feedback loops, then that will be an advance for software engineering.
There's a difference in the tests of that era though. Around the xp times, unit tests were for unit of functionality, not per-method.
“Unit tests are small tests, each one exercising a little piece of functionality. The units tested are usually individual methods, but sometimes clusters of methods or even whole objects.”
Extreme Programming Explained: Embrace Change, 2nd Edition (2004) Kent Beck
Either that or tracing/logging/debugging, but other than specific niches like parsing (of specific bug repros) I think integration tests are generally a lot more bang for the buck.
Anyway, if you want to go down a related-but-unrelated rabbit hole, J.R. Thompson's lecture on the Space Shuttle Main Engines is a good one. You can probably watch it at higher speed to smooth out the many, many "uh"s (believe me, it's bad):
Integrated testing: https://youtu.be/uow6v1EuybE?t=1292
Test to failure: https://youtu.be/uow6v1EuybE?t=3135
https://ocw.mit.edu/courses/16-885j-aircraft-systems-enginee...
--
There's this more-modern link but in true modern fashion you can't really link to specific things presumably because it's all javascript muck: https://openlearninglibrary.mit.edu/courses/course-v1:MITx+1...
Yet, the most unexpected thing happened this year on my team of 4 senior/staff-level developers:
Instead of "splintering/pairing off with AI" individually even further, we wound up quadrupling (mobbing) full-time on our biggest project to date. That meant four developers, synchronously, plus Claude Code typing for us, working on one task at a time.
That was one of the most fun, laser-focused and weirdly effective way of combining our XP practice with people and AI.
Funny how some of it is now day-to-day, and other parts of it would be considered extremely weird.
From your perspective, which bits of XP would you consider weird?
If you pair program with someone else on your team, you both learn what the other is thinking. You both become more familiar with what the code is doing, and why it's doing it.
If you "pair program" with an AI, anything it learned, it forgets as soon as the prompt is closed.
So don't think that's what he's talking about here. He's talking about XP, with humans, just like in the 1990s. There may be some AI in there too, but that's not where the XP part comes from.
If that's not what you're doing, you're likely doing it wrong.
> If you pair program with someone else on your team, you both learn what the other is thinking. You both become more familiar with what the code is doing, and why it's doing it.
Yes.
> If you "pair program" with an AI, anything it learned, it forgets as soon as the prompt is closed.
Same with humans, including your future self. So pair on docs.
TL;DR: You should absolutely be XP pair programming with your LLM.
Maybe we need a new term, maybe we don't, but it's not pair programming if you're doing it with an LLM.
Deleted Comment
If you want AI slop everywhere, that is.
TDD is useful in some situations, yep totally. Pair programming is useful in some situations, yes. Continuous integration; yes, much of the time. Frequent feedback; yes, sometimes, for some types of work which doesn't require deep focus...
It just doesn't work as a blanket 'XP' paradigm because you rarely need all these parts all the time, at the same time. IMO, this is why Extreme Programming lacks gumption as a concept. It feels like a bunch of good ideas thrown together. If there was some kind of synergy between those ideas and practices, the concept of XP would be more important.
As it stands today, everyone is implementing maybe 1 or 2 aspects of XP, but almost nobody is implementing ALL of XP... So nobody can claim that they're adhering to XP.
This is not the same as as 'Agile' because with Agile; the vast majority of big companies are implementing maybe 90% of agile practices, with 70% fidelity... This consistency is enough for companies to identify themselves as 'Agile'. I've worked for many companies which implemented ALL of the Agile practices but not one of them actually implemented them exactly as taught in the Agile Manifesto. I think the closest one I worked for was maybe 90% of the way there; they even followed the story point system exactly and used a packet of cards with numbers on them to allow people to vote during Sprint Planning meetings... but anyway, pretty much all the companies/projects I worked for identified themselves 'Agile' because all the practices fit into a single paradigm and there was value in adopting all of them. After a while, it became easier for project managers to just say "Let's switch to Agile" instead of saying "Let's time-box our development work into short increments, with a planning meeting, refinement meeting and retrospective meeting for each 2-week increment."
For production code I do pretty much all of these, always - at least insofar as it is possible (e.g. willing pairing partner).
Im curious to know under which scenarios you think im doing something wrong. Coz I dont think i am.