# Good boundaries make AI-driven rearchitecture safer

Markdown copy of https://realalpha.app/s/good-boundaries-make-ai-driven-rearchitecture-safer/ on Real Alpha, the best minutes from long interviews with the people building AI. Cite and link the page, not this copy.

- Speaker: [Tibo Sottiaux](https://realalpha.app/builders/tibo-sottiaux/) · Tibo Sottiaux is an engineer who created Codex and head of Core Products & Platform at OpenAI. · Led OpenAI's launches of Codex, ChatGPT Work and the new Dots personal agent platform.
- Host: [Gergely Orosz](https://realalpha.app/people/gergely-orosz/) · Host, The Pragmatic Engineer · Spent four years at Uber heading mobile, web and backend teams; shipped part of its payments system.
- Show: The Pragmatic Engineer
- Episode: [Building Codex with Tibo Sottiaux](https://realalpha.app/v/sLSTM9znQNs/), Sep 9, 2026
- Moment: 52:21 to 56:50 of the episode (4 min), playing on https://realalpha.app/s/good-boundaries-make-ai-driven-rearchitecture-safer/; the episode from there: https://realalpha.app/v/sLSTM9znQNs/?t=3141

## Quote

> “if you sort of like draw the right shape you're going to be able to **change things much more quickly** within the box”
> — [Tibo Sottiaux](https://realalpha.app/builders/tibo-sottiaux/) at [54:15](https://realalpha.app/v/sLSTM9znQNs/?t=3255) · The Pragmatic Engineer

## Takeaways

1. Agents can take on routine maintenance and security upgrades.
2. Rearchitecture that once took years can move much faster.
3. Clear boundaries make changes safer and easier to contain.

## About this segment

Agents can automate dependency upgrades and make major rearchitectures far less costly. Clear abstractions and invariants let teams change one part without destabilizing the rest.

From “Building Codex with Tibo Sottiaux”, Sep 9, 2026. [Watch the full episode](https://realalpha.app/v/sLSTM9znQNs/)

## Transcript

Transcribed by machine (Whisper) from the episode’s audio, so a word may be off here and there.

[52:27](https://realalpha.app/v/sLSTM9znQNs/?t=3147) what do you see maintenance becoming cheaper changing in terms of instead of what you're building, what the ambition is, the, I guess, custom tooling, those kinds of things? Maintenance is really like sort of like a tax that you pay over time just to keep things running. And it's always been necessary, will continue to be necessary, but where I think it changes is like a lot of it is just going to be automated.

[52:49](https://realalpha.app/v/sLSTM9znQNs/?t=3169) So, you know, it's like, okay, you have this third-party dependency. It's like, you don't need to upgrade the version. I'm just like, oh, it's like, you can fully automate this, you know, if you have. good change log and you know and the code is well documented and like you know and and the molecule just like reason through it as you know it can just like blast through your code base do it uh in a couple of hours and you know previously you would have like sort of punted on it because it's not the most fun thing to do but it's actually really important for your business so it's like really important for your project you know especially for security vulnerabilities you want to stay up to date right you want to apply you know all these patches um i think that's just going to be fully automated so a large part of like maintenance it just kind of comes for free

[53:33](https://realalpha.app/v/sLSTM9znQNs/?t=3213) right and then um i think it's it's awesome to also think about before like you know when you wanted to just completely react you have to do like a new architecture because you're trying to make space for like a new you know different kind of trade-offs or you have a new understanding of like the workload or you're trying to fit a new feature and like suddenly you realize like your current system is just very limiting and you need to completely re-architecture it that was like a really really costly endeavor right so you know it's like sometimes like multiple years and i think this is also like super super accelerated now so you like the cost of mistakes uh you know i would say like you know is going down but then at the same time the good old rules i would say of software engineer of like you know having good abstractions like really help like

[54:17](https://realalpha.app/v/sLSTM9znQNs/?t=3257) you know going back to this like having the box with invariants like you know if you sort of like draw the right shape you're going to be able to change things much more quickly within the box and like not affect the rest of the services or the rest of your infrastructure. And I think it's important. It's important to design for very quick iteration and change. I remember when I talked with Peter Steinberger, that was before he joined OpenAI, but about OpenClaw and how he thinks about it.

[54:42](https://realalpha.app/v/sLSTM9znQNs/?t=3282) Like, you know, he told me that he doesn't read the code, but he kept thinking about like, I could see that he's holding the architecture in his head and he was telling me how he re-architects a lot and he thinks about how to make it modular, or how to allow 100 contributors to each build their thing without stepping on each other's toes. So I'm hearing what you're saying that this care, this planning, this structuring has become maybe just a lot more important to like, which was something back in the day, you know, it was like the architect or the staff engineer or experienced folks were doing this thing and other engineers around them were kind of building this, you know, smaller parts.

[55:19](https://realalpha.app/v/sLSTM9znQNs/?t=3319) But it sounds like now all engineers need to be aware of it when you're building your software, right, and plan for it. Yeah, and the GPT models are getting better and better at this as well. Like, you know, thinking about long-term maintenance and, like, good architecture. And, like, this is, like, a natural sort of, like, next step, right? It's, like, not just about code quality in the sense of, like, oh, is this code clean within this file?

[55:39](https://realalpha.app/v/sLSTM9znQNs/?t=3339) But, like, you know, is the architecture actually correct to reduce maintenance burden over time? And, like, you know, make space for, like, future product or feature extensions or changes? and just really this act of like you know engineering over time that's uh kind of like something that models are starting to become capable of like thinking about very well i think it's just kind of fascinating to understand that the software that we're building is just going through the life cycle much much faster right you know before you had you know you were you're scaling you were starting it you know maybe as like a small team of you know yourself maybe a couple of engineers and then you would add engineers like slowly and then you know maybe after a year, you know, it's like if it's very, very successful, you would have 50 engineers on

[56:19](https://realalpha.app/v/sLSTM9znQNs/?t=3379) it or like 100 engineers on it. You would have time to see it coming. You would have time to see like, you know, the humans on board and like, you know, you can think about the documentation, all of that stuff. But now it's just sort of like that explosion of like, you know, suddenly you have like 100 agents contributing to this thing. It's like, you know, that can happen like, you know, in a weekend. And so, you know, you're just going through it at, you know, major, major speed compared to before okay but how do you and and the folks at open ai like deal with it does it