Arshdeep Singh

Really excited for the launch of interaction models! I joined @thinkymachines because I truly believe chatbots are not the final form factor and I don't just want AI to give me a perfect answer when I ask it something. It should always be present, act as a mentor and active participant. Here are some early demos!

A year ago we set out to empower humanity with a focus on multimodal AI, custom models, and open science. We previewed interaction models that collaborate the way people do. Tinker lets anyone train their own open weights models. We published our research on Connectionism.

Announcing Grok 4.5, our first model trained specifically for coding and agents. It was trained with Cursor and offers frontier intelligence at leading speeds and cost efficiency. x.ai/news/grok-4-5

We've trained our best coding model yet, and it's also incredibly token-efficient. Give Grok 4.5 a try!

@soumithchintala 🔥🔥

Bridgewater, one of the worlds largest hedge funds, a Tinker customer talks through how they've carefully fine-tuned a model focused on what makes interesting financial news. Their fine-tuned model is more effective and cheaper than any frontier model.

@bneyshabur @mirendil @a16z @kleinerperkins Congratulations @bneyshabur @shayan_ @aarnogau !!

Today, I’m excited to formally announce @mirendil with my amazing co-founders Harsh Mehta, Shayan Salehian, and Tara Rezaei! We’re fortunate to work with @a16z and @kleinerperkins, who led our seed round of $200M, followed by a major investment from NVIDIA, among others. Mirendil exists to accelerate science and technology, and through them, to help solve humanity's most pressing problems. Self-accelerating AI R&D is the most direct path to delivering on AI's broader promise, which is why we believe the most important application of AI is AI itself. Get this loop right, and it compounds. It fundamentally changes the rate of progress itself across all domains. We believe this capability should be democratized. It should be used to power all scientific efforts trying to innovate at the frontier. There are far more important problems—and broader ones—than any single lab can take on, so more groups should be able to pursue them. This pulls concentration of power away from a few labs: businesses and science labs can own their AI and infrastructure, keep their margins, and control their own destiny instead of ceding it all to a single AI lab. We’re a small team with a singular focus. Our founding team consists of 20 researchers and engineers from frontier institutions including Anthropic, xAI, Google DeepMind, and OpenAI, united by a passion for science and a drive to build the technologies that move it faster. If you want to build the system that builds systems, join us! @HarshMeh1a, @shayan_, @tararezaeikh

@river_ai_inc Congrats @ibab @512x512 @theVincentStark @BigFitzEnergy @chenchen!!!

We are incredibly excited to announce River AI. Our mission is to create personal AI that is owned and shaped by you. Today’s best AIs are controlled by a few large corporations. We are building the alternative: a new, personal stack for AI that works entirely for you, shares your values, and operates on your terms.

Grants for research in interactivity and human-ai collaboration. Up for grabs!

Really excited for the launch of interaction models! I joined @thinkymachines because I truly believe chatbots are not the final form factor and I don't just want AI to give me a perfect answer when I ask it something. It should always be present, act as a mentor and active participant. Here are some early demos!

Cluster magicians and GPU whisperers, come join us! We’re looking for supercomputing engineers to build the infrastructure behind real-time interactive models, Tinker, and large-scale training: scheduling, storage, networking, reliability, and distributed systems at scale. Hiring in NYC and SF job-boards.greenhouse.io/thinkingmachin…

@SeongsikKi5837 @thinkymachines 🤣

@arshdeep @thinkymachines Directionally very very good 🚀

@SeongsikKi5837 @thinkymachines Directionally very good

Long-overdue update: I joined @ThinkyMachines! Excited to share a preview of what we've been building around real-time Human AI Collaboration x.com/thinkymachines…. Demos of our Interaction Models in thread 🧵👇

Today we're sharing our work on interaction models. A new class of model trained from scratch to handle real-time interaction natively, instead of gluing it onto a turn-based one. youtu.be/A12AVongNN4

Thinky's secret plan: 1: Increase Human<->AI bandwidth 2: Raise ceiling of human+AI intelligence 3: Help humans continue as main-characters in the new world We are at Step 1. Interaction Models are great real-time collaborative tools for humans. Here's a preview:

@archanfel_anoth 🐐

I left xAI earlier this year after two incredible years. I joined still early in my career, and had the privilege of meeting many great people and friends along the way. Over time, I ended up leading pretraining across architecture, training, and parts of infra, and later led major RL runs for Coding. Together, we pushed forward generation after generation without missing a beat. None of this would have been possible without the fantastic team. Grateful for my team and friends —their talent and dedication made this possible. Working through hard problems together was the most rewarding part of the journey, and I’ll miss it deeply. It’s hard to walk away from people you’ve spent years building with. But I’m proud of everything we built together, and ready for the next chapter.

Today, we are thrilled to officially launch RadixArk with $100M in Seed funding at a $400M valuation. The round was led by @Accel and co-led by @sparkcapital. RadixArk exists to make frontier AI infrastructure open and accessible to everyone. Today, the systems behind the most capable AI models are concentrated in a small number of companies. As a result, most AI teams are forced to rebuild training and inference stacks from scratch, duplicating the same infrastructure work instead of focusing on new models, products, and ideas. RadixArk was founded to change that. We are building an AI platform that makes it easier for teams to train and serve the best models at scale. RadixArk comes from the open-source community. We started with SGLang, where many of us are core developers and maintainers, and expanded our work to Miles for large-scale RL and post-training. We will continue contributing to both projects and working with the community to make them the strongest open-source infrastructure foundations for frontier AI. We would like to thank our long-term partners, contributors, and the broader SGLang community for believing in this mission. We're also grateful to @Accel and @sparkcapital, NVentures (Venture capital arm of @nvidia), Salience Capital, A&E Investment, @HOFCapital, @walden_catalyst, @AMD, LDVP, WTT Fubon Family, @MediaTek, Vocal Ventures, @Sky9Capital and our angel investors @ibab, @LipBuTan1, Hock Tan, @johnschulman2, @soumithchintala, @lilianweng, @oliveur, @Thom_Wolf, @LiamFedus, @robertnishihara, @ericzelikman, @OfficialLoganK, and @multiply_matrix among others. Thanks for the exclusive interview with @MeghanBobrowsky at @WSJ about our vision.

@aftermultiply @xai 🫡

@arshdeep @xai Godspeed !

After an unforgettable ride, this was my last week at @xai. When I joined in 2024, xAI was a small yet an extraordinary team. I got an amazing opportunity to build our core ML Platforms from scratch and form an ambitious, amazing team. Together we built the core systems that power frontier-model research, evaluations, human data collection, agent training, and daily productivity for every member of technical staff at xAI. It was a true privilege. I’m deeply grateful to @elonmusk and every single person I’ve had the chance to work with across research, engineering, compute, infra, and beyond. The pace, collaboration, and shared mission to understand the universe and be truth seeking have been unmatched. Being able to contribute to data, training, and infra behind Grok-2-1212, Grok 3, Grok 4, 4.2, Aurora, Imagine and many other efforts been the highlight of my career so far. Special thank you to my incredible team and all the brilliant people who made this ride so special. I leave more inspired than ever. Excited for what’s next. Ad astra 🚀

@nnnnikitaaaa @xai Thanks Nikita!

@arshdeep @xai Absolute legend 🐐🫡

@HonghuaZhang2 all the best man!

It’s really been a great pleasure.

@darshan_llm @xai 🤣

@arshdeep @xai you are fun on and off the cricket fields, hope you dont bowl lots of wides in IPL :P