If you use Codex, Tibo needs no introduction. We talked 100% about Codex (fun fact: he started building it!), and 0% about resets. Timestamps: 00:00 Intro 07:21 Working at Google 12:41 What drew Tibo to OpenAI 15:19 The early days of Codex 18:20 Why Codex was built in Rust... 21:15 Why Codex is open source 25:50 Codex plays nice with other models: why? 32:09 How the harness works 36:44 Harness and model improvements 41:19 The SDLC behind Codex 46:39 Code reviews at Codex 52:09 Maintenance and architecture 56:43 How AI tools expand what engineers can do 1:02:30 The Merge: ChatGPT + Codex 1:07:16 How Tibo uses Codex and ChatGPT 1:10:44 Advice for engineers who want to work in AI Brought to you by: • turbopuffer – a vector and full-text search engine built on object storage. It’s fast, cheap, and extremely scalable. • Antithesis – verify your system’s correctness without human review or traditional integration tests – and avoid bugs or outages. • Entire – Git hosting, rebuilt for the agentic era. Entire hosts your code in-region, and is up to 89x faster than any other competitor. Oh, and to those still reading and wondering about resets: there was one yesterday already 😅show more

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@thsottiaux gonna throw this in the ears tomorrow 🙏 ??:??:?? How Tibo is able to keep granting codex usage limit resets

@thsottiaux Loved this episode! Great to see Rust still going strong.

@thsottiaux harness plays nice with other models but somehow never with your rate limit

@thsottiaux I think it’s fair to say we all love @thsottiaux

@thsottiaux Awesome guest, can't wait to listen to this one! You've had some banger episodes lately, keep it up!

@thsottiaux I really want to watch this interview with our favorite reset guy. 😊 Thank you!

@thsottiaux I see 'sponsored by turbopuffer' → I press ignore. Those guys are promoting their BS platform everywhere using all kinds of shady techniques.

@thsottiaux Will watch later... gonna go touch grass for now.

@thsottiaux Watched the whole thing this morning - the part where Tibo says the early Codex days were mostly guesswork about what devs actually wanted hit home. Did building it teach you anything about tool design you couldn't have guessed before shipping?

@thsottiaux He looks really tired after hitting all the reset buttons

@thsottiaux The interesting bit is that Codex was built around the harness, not jusess owns the loop, model swaps stop being a rewrite. That’s the part most “agent” demos politely hide.

@thsottiaux Tibo never laugh. weird.

@thsottiaux The early history matters because it separates the constraints that shaped Codex from the capabilities we now project onto coding agents. I’m curious which limitation most influenced the current workflow of letting the agent act, then reviewing its work.

@thsottiaux Your surveys catch what dashboards miss: policy versus practice. One split that never gets published: AI coding tool usage by seniority. Does your data show juniors shipping faster while seniors review more?

@thsottiaux 最想听 Rust 和开源那两段，Codex 早期也太有意思了

@thsottiaux the useful part of these conversations is the design intent behind the defaults. understanding why delegation, isolation, and verification work the way they do helps builders use the product better than another feature list.

@thsottiaux Can’t wait to watch the Gergely Orosz interview on Codex and OpenAI. Thanks, reset legend!

@thsottiaux The Reset Dealer himself!

@thsottiaux Who is Tibo?

@thsottiaux Interesting perspective

@thsottiaux 0% resets is an impressive feat for a Codex interview this week. The early-days section sounds like a good place to start.

@thsottiaux Guaranteed banger. Gotta watch this

@thsottiaux codex adoption now hinges on sandbox reliability more than model quality, was that clear early

@thsottiaux The section on other models caught my eye. I'd want to know how much of the workflow survives a model swap without having to rewrite all the instructions.

@thsottiaux Totally agree with this