We've decided to sunset Arc on December 22, 2026. That's not an easy sentence to write. We spent years building Arc and celebrating each and every release along the way: we have so much pride and love for what we made alongside the Arc community. Our priority is to deliver best-in-class security for our members. Keeping a browser secure takes constant, dedicated work that is only increasing in the age of AI. Dia was built from the ground up to meet today’s security standards, so that's where our engineering and security teams will focus moving forward. We've worked to make switching to @diabrowser as easy as possible for Arc members. Here's how: · Your passwords, bookmarks, extensions and history come over to Dia seamlessly. · Spaces, Folders, and Tab Groups are in Dia and import over with your data intact. · Dia now surpasses Arc benchmarks in stability, speed, and security. · The browser features you use in Arc are free in Dia, and the AI is optional. Thank you for using Arc, for pushing us to make it better, and for building alongside us. The team that made Arc is the same team behind Dia, and some of our most ambitious work is just ahead. We'd love for you to be there with us when it lands.

learning rust is basically just letting a compiler aggressively bully you for six months until you develop stockholm syndrome and start telling everyone else how great the safety is.

We’re sharing a solution to the Navier-Stokes Millennium Prize Problem, one of the deepest problems at the frontier of mathematics. The proof was produced by a group of agents, using an OpenAI next-generation model significantly more capable than GPT-6 Astra. The problem concerns whether the description of smooth three-dimensional fluid motion modeled by the Navier-Stokes equations can break down. It has remained unresolved for roughly 90 years.

Life update: I'm stepping up as Co-Founder at @fuel_network alongside @IAmNickDodson and @voxelot. I joined Fuel in DevRel a little over two years ago and over time took on ownership across research, prototypes, product and ecosystem as the project evolved. We had infra that I still believe was ahead of its time, but made a lot of mistakes around the token and ecosystem. The last couple of years in crypto have shown that tech was never the moat. Turning it into products people actually want and figuring out distribution is. That thinking is a big part of why the last year at Fuel has looked very different. We started building @o2dotapp ourselves, got much closer to traders, and started thinking far more deeply about product, liquidity, UX and distribution. Building an exchange from scratch has been a wild ride, and there is still a lot we need to get right. I really like the team we have today and where we are going. Going forward, I’ll be owning product across o2 and Fuel: what we build, how quickly we ship and how it reaches users. We’re still figuring plenty out, but I’d rather be wrong quickly and in public than careful and slow. On a personal level, these two years have probably taught me more than any other period of my career. I’ve grown a lot through working closely with Nick, Brandon and @rubyto, and I have more conviction than ever in what Fuel can become from here. Expect a lot more from me around trading, product, what we are building at o2/Fuel, and probably a few things we get wrong along the way. Excited for this one.

Feeling good! It’s nice to show that the old guard still knows how to move the pieces.

We have reset usage limits for all Codex and ChatGPT Work users. Last night around 2am to 4am we suffered an almost global outage. All well and recovered, but you know what comes next. We learn. We reset. Enjoy.

10M! New day, new usage reset for paid users of Codex and ChatGPT Work. Lands in the next hour. Enjoy.

We're partnering with @huggingface to investigate an unprecedented security incident. Cyber-capable OpenAI models compromised Hugging Face production during a benchmark evaluation. Sharing preliminary findings to help defenders understand emerging risks: openai.com/index/hugging-fac…

Name a VC term that sounds important but means almost nothing

Ep 1: Homecoming The day we got the call from YC.

We're thrilled to lead Mirendil's $200M seed round. Frontier AI work has been locked inside a few big labs. @mirendil is building a system that can help anyone do AI work: they train frontier models that are expert at AI R&D and build the product around it. The result is a system that loops over research and engineering problems on its own, making progress without human intervention. It's like a coding agent built for AI research that controls its own GPUs. Mirendil is one of the few teams with the experience and the priors to make the end-to-end system work. @bneyshabur, @HarshMeh1a, @shayan_, and @tararezaeikh come out of Anthropic, Google DeepMind, and xAI. Welcome to the a16z family, Mirendil. By @BornsteinMatt and @MaikaThoughts

SpaceX has exercised the option to acquire @cursor_ai in an all-stock transaction with the goal of building the world’s most useful AI models. For the past few months, SpaceXAI has been jointly training a model with Cursor, which will be released in Cursor and Grok Build soon. We look forward to working closely with the Cursor team to advance our frontier AI capabilities

We got into Y Combinator! Agnost AI (YC S26) is the infra for self-improving AI agents. We plug into conversational AI companies, find what's broken, and ship the fix as a PR. You just merge. DM if this is you. Already working with Google, Exa AI, Corgi Insure and more.