The Ledger
Every statement that passed quotation and attribution checks. Mix any filter with any other: certainty 1/5, debate potential 5/5, or both at once.
why aren't all 42 resolved? a statement only gets an assessment when the public record can support or contradict it. opinions and what-ifs never can, and 1 checkable ones are still open, waiting for their date. predictions held up or didn't; assertions are supported or contradicted. on every card: ▮▮▮▮▮ certainty · ▮▮▮▮▮ debate potential. speakers are clickable
Lopopolo: Coding models and harnesses are now isomorphic to human engineering capability
“The models are there enough. The harnesses are there enough where they're isomorphic to me and capability and the ability to do the job.”
Slack: AI tools like Cursor and Claude Code will peak and decline
“A lot of these other tools that are great, like cloud code and codex and cursor and so on that they've forgotten what made them great and what made them grow so fast, which is building the very best product. And they built it in a way that's too overfit on the…”
Swyx found Codex preferable to human marketing consultants for ads
“Codex has been my CMO for the last like two months. Basically running our ads and giving me advice on AEO and SEO and what have you. And I find it much more preferable to talking to a real human consultant, which I've also done. And it's roughly the same resul…”
Codex Wrote Complex SYK Physics Simulation in 10 Minutes
“Codex just wrote up a simulation of the SYK model. This is like a very technical thing in quantum mechanics and gravity. And like, yeah, a lot of research groups have been trying to run this simulation and it couldn't do it. And Codex did it in 10 minutes.”
Lopopolo: Native code guardrails outlast external model scaffolds as AI advances
“If we were building an entire separate Ross scaffold around Codex to restrict its output, that I think would be like additional harness that would be prone to being scrapped. But yeah, if instead we can build all the guardrails in a way that's just native to t…”
Lopopolo: Autonomous Coding Removes Human Language Familiarity Constraints
“No humans in the loop here. So like my, Own personal ability to write or not write Elixir doesn't really have to bias us away from using the right tool for the job, which is just wild.”
Lopopolo: Collapsing product problems into code allows Codex harnesses to solve them
“If you can figure out how to collapse a product that you're trying to build a user journey that you're trying to solve into code, it's pretty natural to use the codex harness to solve that problem for you.”
O'Laughlin: AI Agents Will Write 25% to 50% of Public Code by Year-End
“I sandbagged the ever-living share of that. I just believe 25 is, Very, like, I, like, it's like a, the rate it's on is like, whatever, 50 or something like that, but I think, I feel, I wanted to give a 95 confidence interval. I think 25 is within the 95 confi…”
Fioca: Has not hand-written a single line of code in months
“I haven't written a single line of code by hand in months, because I know what I can trust it to do.”
Claude 3.7 Sonnet post-training heavily biases the model toward CLI tools
“So for example, Sonnet 3.7 clearly has it smells like cloud code, right? Same with codex. It very much impacted the way that those models want to write and edit code such that they seem to have a personality that wants to be in a CLI based tool.”
Nathan: OpenAI sequencing agents from developers to knowledge workers to everyone
“The vision is like bring useful agents to everyone. We started with like developers Historically are like early adopters that are willing to put up with more friction, set things up, et cetera. Like that's where, you know, Codex started. I think the next oppor…”
Kolter: Concentrated Foundation Model Usage Creates Systemic Correlated Security Exploits
“And especially when there's the possibility of correlated failures, right? So it's not just that there's a lot of AI systems out there, it's that there's actually a few models that everyone is using. And if you find vulnerabilities in the agents that everyone …”
Lopopolo: Standardizing codebase structure and skills maximizes AI agent effectiveness
“I do think that there is leverage to be had in making the code and the processes as much the same as possible. If you think that code is context, code is prompts, it's better from the agent behavior perspective to be able to look in a package in directory XYZ …”
Lopopolo: PR review agents initially caused non-convergence by bullying author agents
“Initially the codex driving the code author was willing to be bullied by the PR reviewer, which meant you could kind of end up in a situation where things were not converging.”
Lopopolo: Codex authors Grafana dashboards and handles on-call incident paging
“Like the dashboard thing you mentioned, we have Codex authoring the JSON for the Grafana dashboards and publishing them, and also responding to the pages, which means when it gets the page, it knows exactly which dashboards are defined and what alerts. What al…”
Lopopolo: OpenAI used iterative Codex loops to generate Symphony specs
“Like we have taken all the scaffolding that has existed in our proprietary repo, spun up a new one. Ask codex with our repo as a reference. Write the spec. We tell it, spin up a tmux, spawn a disconnected codex to implement the spec. Wait for it to be done. Sp…”
Lopopolo: OpenAI uses an automated landing skill to delegate PR merges to Codex
“We invoke a dollar land skill and that coaches codecs to push the PR, wait for human and agent reviewers, wait for CI to be green, fix the flakes if there are any Merge upstream if the PR comes into conflict, wait for everything to pass, put it in the merge qu…”
OpenAI Frontier runs daily agent loops over team logs to update repositories
“We're actually slurping these up for the entire team into blob storage and running agent loops over them every day to figure out where as a team can we do better? And how do we reflect that back into the repository? Yeah, though, everybody benefits from everyb…”
Lopopolo: Optimizing AI debugging workflows for human legibility is wrong
“Optimizing for human legibility of that debugging process was wrong. It kept him in the loop unnecessarily, when instead he could have just like codex cooked for five minutes and gotten the same.”
Lopopolo: OpenAI uses incident pages to update repository reliability rules via Codex
“When we get a page because we're missing a timeout, for example, I can just add codecs in Slack on that page and say, I'm going to fix this by adding a timeout. Please update our reliability documentation to require that all network calls have timeouts. So I h…”
Lopopolo: Codex reviews internalized dependencies with less friction than upstream patching
“When we deploy Codex security on the repo, it is able to deeply review and change The internalized dependencies in a much lower friction way than it would be to like push patches upstream, wait for them to be released, pull them down, make sure that's compatib…”
Lopopolo: OpenAI inverts harnesses by having Codex spawn dev environments
“One neat thing here is we have tried to invert things as much as possible, which is instead of setting up an environment to spawn the coding agent into, instead we spawn the coding agent, like that's the entry point, just codex, and then we give codex via skil…”
Levie: Autonomous agents require hard-mode governance unlike current user-impersonating tools
“So far we've been in, in easy mode. We've hit the easy button with AI, which is the agent just is you. And when you're in cloud code and you're in cursor and you're in codex, you're just, the agent is you, you're offing into your services. It can do everything…”
Casado: Codex is better than Opus 4.5 at solving hard coding bugs
“Listen, Codex, in my experience, is for sure better than Opus 4.5 for coding. Like, it finds the hardest bugs that I work in with, like, it's, you know, the smartest developers I don't work on it.”
Fioca: Coding agents enable self-customizing software by writing integrations at runtime
“So now if it doesn't have a tool, it can make a tool that it needs to solve a problem, right? So that's like another layer of abstraction and it's not just coding. You can write software that has an agent that can spin up a codex instance and write a custom pl…”
Chen: Codex performs better when search tools are named 'rg' over 'grep'
“So if you call it grep, it actually does a little bit Worse. But if you call it RG, it actually does really well.”
Chen: Naming custom tools identically to terminal tools boosts Codex performance
“We found some, like, partners of ours, like, they discovered that what you can do is that you can actually still have a lot of the tools just named in the same way as the terminal tools, as well as having the same input and output. And all of a sudden, the too…”
Nathan: OpenAI plans to keep developing Codex specifically for developers
“Like, I think we fully intend to like, you know, treat developer, like developers have been, you know, a core market for us for so long. And like, there's so much more that we can do to make Codex great specifically for software development, and we'll continue…”
Swyx: OpenAI will always release both general and Codex model variants
“I'm pretty, like, have pretty high confidence that basically OpenAI will always release a GPT-V and a GPT-V codex.”
McGrath: Design specs let Codex complete hours of coding in 15 minutes
“If I spend, like, you know, 30, 40 minutes writing something that looks like a design doc or something, Codex can do more work than I can do in a few hours in, like, 15 minutes.”
Chen: AI software abstraction is shifting from raw models to packaged agents
“So we're actually shipping this Entirety, entire agent altogether, then you can actually build on top of that agent. That's one of the patterns that we're seeing here is rather than focusing on optimizing with every single model release, you're actually just b…”
Fioca: GPT-5 matches Codex coding capability but adds step-by-step preambles
“With the five series, because it's more general, and it's just about as good as coding as codex for a lot of things. We've taught it to be more communicative. And so it has preambles before tool calls. It'll say things like, I'm about to go look for this.”
Huang: Building Visual Agent Builder in under 2 months required Codex
“For the Visual Agents Builder, we only started that Probably less than two months ago, and that, that wouldn't be possible without Codex.”
Brockman: Future dev architecture will combine local, remote, and multiplayer agents
“And then you have your codex infrastructure that has a local agent and a remote agent, and that is able to seamlessly, you know, interplay between the two and then is able to multiplayer. Like, this is what the future is going to look like, and it's going to b…”
Nathan: Codex and ChatGPT Work share the same underlying agent harness
“So the harness is the same. The harness is shared. On, In both of the products, we made improvements to the harness to make it good for knowledge work, especially as it relates to plugins or computer use or artifacts. You get that power regardless of what your…”
Zaharia: Databricks built Isaac as an internal wrapper for Claude Code and Codex
“We have a really great dev info team. They built something called Isaac that's basically like a wrapper on cloud code and codex and let's you use them either on the web and like, Sandboxes or just on your dev machine or on your laptop or whatever.”
Lopopolo: OpenAI feeds 12-month business vision and customer context to agents
“One thing that's in core beliefs.md is like,
Who's on the team, what product we're building, who our end customers are, who our pilot customers are, what the full vision of what we want to achieve over the next 12 months is.
Like these are all bits of context …”
Lopopolo: Codex can run background builds while concurrently reviewing code
“It basically means that Codex is able to spawn commands in the background and then go continue to work while it waits for them to finish. So it can spawn an expensive build and then continue reviewing the code, for example.”
Chen: Approximately 50% of OpenAI employees adopted Codex at launch
“Initially when Codex first launched, it was around 50% of folks that open AI started using it.”
Fioca: GPT-5.1 allows disabling preambles, unlike the reasoning-dependent Codex model
“So Five One, you can turn that off, you can prompt it not to do that, but the Codex model can't actually do that, and it relies on the reasoning summarizer to give you that update.”