Alongside my co-founders, proud to formally announce @mirendil. Our mission is to accelerate science and technology through democratizing frontier AI R&D. If you share our excitement for this mission, reach out to us!

. @Mirendil 🤝 @Google

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

It doesn’t need to be this way. It should not be this way. It should not be OpenAI/Anthropic deciding which fields get accelerated. To truly accelerate science and technology, self-accelerating AI R&D must be democratized. In fact, this is the exact motivation behind Mirendil.

We are building a frontier lab to ensure scientific progress is no longer bottlenecked by the speed of AI R&D. Our first memo is live at: mirendil.com. Join us!

Career update: I left xAI to start something new, closing my 7+ year chapter working at Twitter, X, and xAI with so much gratitude. xAI is truly an extraordinary place. The team is incredibly hardcore and talented, shipping at a pace that shouldn’t be possible. From the Home Timeline at X to Grok 2, 3, and 4 at xAI, I worked across product infra and model behavior post-training, from memory to coding infra, agents, and more. Pure startup mode, every day. Working closely with Elon across X and xAI, I saw what happens when you refuse to accept impossible as an answer. I learned to embody obsessive attention to detail, maniacal urgency, and to think from first principles. I’m deeply grateful to @elonmusk for the experience, to @wanghaofei for the trust and support throughout Twitter/X, and to @TheGregYang and @ibab for believing in me. And to the many incredible people I had the privilege to work with along the way, thank you! Now, I’m excited to take the leap and build something new, focused on accelerating science. More soon.

Career Update: I've left Anthropic to start something new. Anthropic is a magical place — amazing people, strong culture, and unmatched taste. I have a lot of respect for my friends and ex-colleagues, and knowing them, I'm confident they'll do the right thing, especially when the choices are hard. I feel grateful and proud to have been part of the journey with them. Excited to start a new chapter — stay tuned for more!

I've left Anthropic to start something new. 🧵

From trusted source in Tehran: Tell all of your friends [abroad], everyone you know: there is absolutely nothing else we can do here inside Iran. Nothing. They are killing people in such ways, they’ve descended upon people so brutally, they're attacking us in such ways... We’ve lost so many lives that no one dares go out anymore. They shoot directly with bullets. They kill outright. And even after killing, they come and behead you, and do countless other violent things to you. For God’s sake, whatever can be done, you are the ones who can do it. You must not abandon these gatherings. All of you must keep these protests going. We cannot do anything inside Iran. Going out into the streets is literally suicide. It’s not about bravery anymore. It’s madness. You go out and they shoot you point blank. They don’t even ask why you came. They just kill you. There is absolutely no way for us to gather unless we had weapons, unless we were armed like them. Otherwise they have weapons everywhere. There has been so much killing. So much. So whatever is to happen now is up to you. You are the ones who can somehow save us. [Breaks down into a sob. Crying, the caller continues...] When you see what’s happening, when you hear what’s happening… I’ve done so much yelling and choked on so much teargas, my voice is bad. We follow what you're doing. When we see you gather in protest in front of an embassy it brings us joy. It still gives us a lingering hope that we can do something. It's your responsibility now. We did absolutely everything we could. As our fellow Iranians it's your responsibility. You can influence foreign policy. You can tell the world what's happening. The placards you hold. The YouTube videos. Distributing images and video. Gathering in front of embassies. Even if you have just the weekends. Please do something for us on Saturdays and Sundays. Please don't let your gatherings get smaller as the weeks go on. No one will stop you there. No one will kill you. No one is singling you out. We don't even have the freedom to walk about in our own town. We no longer even know who is friend or foe. We don’t even know who we’re speaking to anymore. We no longer know if those recounting what's happening is an enemy. Because if one wrong word slips from our mouths, they turn us into a corpse even before we've had a chance to return home. For God’s sake, I beg of you, don’t abandon these gatherings. Our only hope now is you. What’s now obvious is that America won’t do anything. You’re our only hope. Please tell your friends. You’ve seen how many young people have been killed. So many, so many young people. For the sake of the youth. I know that based on the videos that have reached Iran International [satellite station] since yesterday, now that the internet has come back briefly, they will probably cut the internet again and people will go into silence, the country will go back into a blackout. For God’s sake, please help us. Help us save our country from these people. Stand together so we can live in a flourishing country. For God’s sake, help us. We are in Tehran. What I saw in Tehran, and what they’re saying about the provinces and small towns... They couldn’t fully control Tehran’s gatherings with the forces they had, but in the small towns it was killing after killing. Towns with populations of only 20 or 30 thousand people truly had many deaths. Thousands, hundreds… The things we’ve heard, the things we’ve seen go far beyond mass killing. It was horrific. Truly horrific. I beg you. I beg you. Don’t abandon these gatherings. Please. #Iran #IranMassacre

After 100 hours of total internet blackout, Iran carried out one of the worst massacres of modern times.💔 Over 20,000 killed in 4 days. Hospitals attacked. Doctors prosecuted for saving lives. 800 people now on death row. #R2PforIran #IranMassacre

#DigitalBlackoutIran 😞😠

⚠️ Confirmed: Live metrics show #Iran is now in the midst of a nationwide internet blackout; the incident follows a series of escalating digital censorship measures targeting protests across the country and hinders the public's right to communicate at a critical moment 📉

It was great hosting an amazing group of hardcore engineers for the last 24 hours. Here are the highlights of the top projects. 🚀🧵

I just got @shayan_ from the X Handle Marketplace! Get your own at handles.x.com

Proud to have been part of the post-training team working on Grok 4.1 over the past few months. It was a big team effort, and seeing the quality jump along with #1 and #2 on LMSYS feels amazing. Can’t wait for people to try it. 🚀

🥇grok 4.1 thinking 🥈grok 4.1

You'll love chatting with Grok 4.1!

My companies are, surprisingly in some ways, trending towards convergence