Leading Reinforcement Learning at @Reflection_ai. Scaling RL for frontier reasoning models. Formerly @OpenAI, @GoogleBrain and @stanford_ee.

San Francisco, CA
Joined December 2017
Behrooz Ghorbani retweeted
Incredibly proud of @reflection_ai for immediately jumping into the #2 spot for US open models with their first ever model. Beam is SO fast and efficient for its size. Check it out
Artificial Analysis
@ArtificialAnlysOct 16
Reflection’s first model, Beam, scores 30 on the Artificial Analysis Intelligence Index, placing it #2 among US open weights models Beam is an open weights model with 501B total and 23B active parameters, released on @huggingface Congratulations to @reflection_ai on the release! Key takeaways: ➤ Second among US open weights models: Beam scores 30, behind only Meta's Muse Spark Open (39) and ahead of yesterday’s NVIDIA Nemotron 3.5 Super VL (26) release. Outside China, only Muse Spark Open and the UAE's K2 Horizon (31) score higher ➤ Token efficient for its intelligence: Beam uses ~26k output tokens per Intelligence Index task compared to K2 Horizon, one point ahead, which uses twice as many (~52k). Proprietary models still set the frontier, with GPT-6 Astra (max) scoring 53 on the same budget (~27k) ➤ Strong on agentic workflows, weaker in the terminal: Beam scores 48.5% on AutomationBench-AA, 11 percentage points ahead of K2 Horizon (37.2%) and level with Qwen3.8 27B (48.2%). Terminal-Bench 4.0 is a weak point, where Beam scores 3.0%, behind Qwen3.8 27B (5.6%) and Muse Spark Open (8.1%) ➤ Knows more, guesses more: On AA-Omniscience it answers 33% of questions correctly, well ahead of K2 Horizon (18%) and Qwen3.8 27B (16%). But its hallucination rate is 47%, against 26% for K2 Horizon and 30% for Qwen3.8 27B, giving Beam a net index score of 1.5, ahead of both peers (−3.0 and −10.0) Other model details Context window: 1M tokens Modalities: Text Parameters: 501B / 23B
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Behrooz Ghorbani retweeted
Reflection
@reflection_aiOct 16
Beam is now available across platforms, with open weights under the Apache 2.0 license - in collaboration with an ecosystem of 40+ partners. We're releasing: - Weights, tokenizer, and reference implementation - BF16, FP8 and NVFP4 weights and a DFlash2 drafter - The open source harness we built and trained Beam on: Mirror CLI Weights and model card on Hugging Face: huggingface.co/reflection
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Behrooz Ghorbani retweeted
This was the first big run we've done at Reflection. We had a so much fun running a lot of RL on this one! It was very satisfying to see scaling RL in action with no plateau in sight!
Reflection
@reflection_aiOct 5
Introducing Beam: a highly efficient agentic open model with 501B total parameters and 23B active. - Frontier reasoning efficiency - Advances the Western open frontier on coding & agentic tasks - Trained end-to-end from scratch Full weights release this month. Learn more about Beam: reflection.ai/beam
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Behrooz Ghorbani retweeted
I really liked Reflection CEO @MishaLaskin's framing on the state of closed vs. open AI models: "Closed models are the equivalent in real estate to renting an apartment... As AI adoption has increased, an ownership market is basically coming in.. The only way to own intelligence, by definition, is if it's open"
Reflection’s founders on building a DeepSeek of the West Reflection is soon releasing Beam, its first open-weight AI model, in a bid to become the DeepSeek of the West. Trained from scratch, Beam is designed for coding, reasoning, and AI agents. Reflection's benchmarks put it alongside the strongest open models, with substantially more efficient token economics. To mark Beam’s debut, I'm joined by Reflection's co-founders: CEO @MishaLaskin, who led reward modeling for Google’s Gemini, and CTO @real_ioannis, who helped create AlphaGo and AlphaZero before leading Gemini’s RLHF effort. Reflection has raised $4.6 billion from investors that include Nvidia, Sequoia, and Lightspeed. We discuss why Chinese labs pulled ahead in open AI models, how Reflection built Beam, and why the founders think companies and countries will increasingly want to control their own models. I ask how they plan to make money from open-weight AI, whether openness can make these systems safer, and what comes next for Reflection. Timestamps: 00:00 Why open models are surging 01:06 Renting vs. owning intelligence 03:40 Open models catch up 05:53 Why China led open AI 08:03 Introducing Beam 10:05 Scaling reinforcement learning 14:09 Training from scratch 16:04 Safety, alignment and openness 32:29 The Reflection origin story 37:32 Making money on open models 42:33 Vertical integration and compute 48:45 Partnerships and distribution 56:46 What’s next for Reflection Links: podcast.sources.news/ Spotify: open.spotify.com/show/3p1KZv… YouTube: youtu.be/BKnAeVej0dc Substack: sources.news/p/reflection-fo… Thanks to the show’s premier sponsors: @Atlassian, @meetgranola, and @mercury.
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Behrooz Ghorbani retweeted
the chinese open weight frontier has been running without a serious western peer for a while, but today reflection dropped beam! underneath there's a super solid team: - ex-deepmind founders (@MishaLaskin / @real_ioannis) - $4.6b raised, - $25b mark, nvidia in the round. - 23.8t pretrain on 6,144 GB300s - then 10.5k gb300s for four weeks of rl - 100m+ rollouts - locked spacex colossus GB300 capacity - locked $1b $NBIS compute deal (we announced this few months ago, letsgoooo) - 501b total, 23b active, sparse MOE, trained from scratch, coding and agents first. On their numbers it basically ties glm-5.2 on the agentic coding rows that matter for a workhorse: - deepswe 44.4 vs 44 - terminal-bench 80 vs 81 but all this while using roughly 3 to 4x less inference compute for similar reasoning scores, quite cool! it still trails glm-5.3 and deepseek v4.1 flash on those same benches tho (flash is a different animal anyway: tiny active count, multimodal). And yes kimi k3 stays ahead on raw capability. So yes the western push is real, but part of product is efficiency (at least on this one) closed frontier (opus / astra lvl) still owns the top of the capability curve but Beam isn’t pretending otherwise. i guess it's fair if you compare open to open, and having a western model you can own that sits in glm 5.2’s neighborhood at a fraction of the reasoning compute, is quite impressive as Laskin said: closed models are renting an apartment, an ownership market is forming. This is the first well-funded western open workhorse built for that
We are introducing Beam today, a 500b open model that excels in coding, agentic, and scientific workloads. Beam is very token-efficient, pre-trained from scratch, and scaled with the largest RL run documented openly we are aware of. Getting here was challenging, rewarding, and personal. I immigrated to the USA during childhood when my parents got jobs as scientists at PNNL, a national lab located in a rural town in Washington state. Growing up, I developed an interest in physics because it was grounded in simple principles, was foundational, and had long-term impact. Physics was the foundational science of the 20th century. The first general computer (ENIAC), the transistor, GPS, and much of modern technology had its roots in physics. In 2016, during my graduate studies, I noticed the birth of a new foundational science - Artificial Intelligence. AlphaGo, the superintelligent Go agent developed by DeepMind, had come out and made me feel what was about to come. A neural network, trained to imitate human players, and then improve itself through trial and error, mastered the most intellectually challenging board game in the world. What surprised me about AlphaGo is how it was conceptually simple, general, and scalable. The system could in principle improve itself forever, it was just a function of compute. This is when I became “AGI pilled” as they say. I switched from physics to AI because I thought this would become the root node science of the 21st century, much like physics was the root node science of the 20th century. I believe that working on foundational science is not enough on its own. Foundational science must also remain open and widely accessible. We remember Newton for his contributions to physics, but he was also an alchemist. Alchemy was done in secret, because the artificial production of gold was deemed lucrative but also dangerous with the potential do destroy entire economies. Newton even wrote his alchemy notebooks in cypher. On the other hand, Principia was published in the Philosophical Transactions of the Royal Society, the knowledge was made widely available, passed down for generations in what we now call Newton’s laws. The computer, transistor, GPS were possible to build because physics as a science was open. Openness creates an ecosystem of innovation. The notion of openness, which is a core tenet of scientific discovery, has also become a guiding principle for how foundational technology gets built and distributed. The internet was built on open protocols. The most widely used operating systems are open. The field of cybersecurity exists because strong encryption protocols were made open in the 1990s. Open also means safer. The best defence is a distributed one. Commonly used open source software is robust and battle-tested because it is inspected and patched by a community of developers. AI is different but also similar to software in many ways, though with a much larger surface area of vulnerabilities. It is impossible for a small group of safety researchers working in secrecy to remediate all of the potential issues regardless of their intentions. It is like entrusting a handful of white blood cells to protect your body. AI is both foundational as a science and a technology, and the safest way that also ensures the benefits of AI are distributed evenly is by making it open. I’m excited for what developers and scientists build and learn from this model, and for Beam to play a small part in ensuring that AI is made widely accessible, safe, and beneficial to all.
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Behrooz Ghorbani retweeted
Reflection
@reflection_aiOct 5
We scaled Beam with the largest publicly documented RL run we’re aware of, which ran on 10.5k GB300s for 4 weeks. Algorithmic advances coupled with distributed infra enabled an RL system that scales. Across our eval suite, capabilities continued to improve as we increased RL - with no signs of plateau.
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Behrooz Ghorbani retweeted
Artificial Analysis
@ArtificialAnlysOct 5
Artificial Analysis has been given access by Reflection and is independently benchmarking Beam Early indicators suggest Beam will be one of the most token-efficient open models we've seen for its level of intelligence. Congratulations @reflection_ai on the announcement!
Reflection
@reflection_aiOct 5
Introducing Beam: a highly efficient agentic open model with 501B total parameters and 23B active. - Frontier reasoning efficiency - Advances the Western open frontier on coding & agentic tasks - Trained end-to-end from scratch Full weights release this month. Learn more about Beam: reflection.ai/beam
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Behrooz Ghorbani retweeted
Flash models are where the volume is. DeepSeek V4.1 Flash and GLM 5.3 Flash lead OpenRouter’s 30-day token rankings. The models people actually deploy deserve more attention. This is why Reflection’s Beam matters. It has 501B total parameters but activates only 23B per token. Reflection reports GLM-5.2-class reasoning on selected benchmarks at roughly one-quarter to one-third the estimated generation compute. Open weights give developers another way to improve those economics. Beam’s Apache 2.0 release is planned for later this month, allowing developers to customize the model and optimize how they serve it. Reflection is bringing frontier intelligence to an economically useful parameter size, then letting everyone build on it, unlocking an enormous amount of latent demand.
Reflection
@reflection_aiOct 5
Introducing Beam: a highly efficient agentic open model with 501B total parameters and 23B active. - Frontier reasoning efficiency - Advances the Western open frontier on coding & agentic tasks - Trained end-to-end from scratch Full weights release this month. Learn more about Beam: reflection.ai/beam
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Behrooz Ghorbani retweeted
Introducing Beam: frontier reasoning at 4x the efficiency of today’s leading Western open models. Beam is the first in a series, and we’re just getting started. We want to put more control in users hands - with sovereignty, continuity, and lower costs - and help grow a strong U.S. open ecosystem where frontier labs build on each other’s work and push one another forward. What a team. What a moment. So proud of the people behind this and so grateful to be part of it.
Reflection
@reflection_aiOct 5
Introducing Beam: a highly efficient agentic open model with 501B total parameters and 23B active. - Frontier reasoning efficiency - Advances the Western open frontier on coding & agentic tasks - Trained end-to-end from scratch Full weights release this month. Learn more about Beam: reflection.ai/beam
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Behrooz Ghorbani retweeted
It’s a huge honour to be part of the team building the open weights frontier. 🙏 Super excited for everyone to try this!
Reflection
@reflection_aiOct 5
Introducing Beam: a highly efficient agentic open model with 501B total parameters and 23B active. - Frontier reasoning efficiency - Advances the Western open frontier on coding & agentic tasks - Trained end-to-end from scratch Full weights release this month. Learn more about Beam: reflection.ai/beam
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Congrats to Reflection for launching their first model! It took a while but they got there😄 Looks like a GLM-5.2-level model, perhaps the best American open-source model? Weights will be released soon... Overall, it's great to have another strong open-source player in the US
Reflection
@reflection_aiOct 5
Introducing Beam: a highly efficient agentic open model with 501B total parameters and 23B active. - Frontier reasoning efficiency - Advances the Western open frontier on coding & agentic tasks - Trained end-to-end from scratch Full weights release this month. Learn more about Beam: reflection.ai/beam
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Behrooz Ghorbani retweeted
Today, we’re introducing Beam, Reflection’s first model. A year ago, we set out to build a frontier open model before we had much of the team or infrastructure required to do it. Since then, Reflection has grown 10x. We assembled an extraordinary technical team of researchers and engineers I feel privileged to call my colleagues, alongside a world-class group across recruiting, business, policy, operations, and the rest of the company whose work made all of this possible. At the same time, we built the science, data, software, and infrastructure behind the model itself. In July, we started pretraining Beam and weeks later, we had a 500B-parameter model at the frontier of Western open intelligence—particularly strong at agentic coding, with remarkable reasoning efficiency. What makes me proudest, though, is our team. The relentless focus, speed of execution and the willingness to own and solve whatever problem was in front of us. And, most importantly, the commitment of this team to our mission. Beam is our first milestone toward our mission of building open intelligence and making it accessible to everyone. We’ll release Beam’s weights, model card, and tech report later this month. And we’re already training the next, larger model. Over the past year, we built the team and the engine to propel us to the frontier and that’s what makes me so excited about what comes next.
Reflection
@reflection_aiOct 5
Introducing Beam: a highly efficient agentic open model with 501B total parameters and 23B active. - Frontier reasoning efficiency - Advances the Western open frontier on coding & agentic tasks - Trained end-to-end from scratch Full weights release this month. Learn more about Beam: reflection.ai/beam
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Behrooz Ghorbani retweeted
Fun time cooking this up with an awesome team! More to come soon 🚀🚀🚀
Reflection
@reflection_aiOct 5
Introducing Beam: a highly efficient agentic open model with 501B total parameters and 23B active. - Frontier reasoning efficiency - Advances the Western open frontier on coding & agentic tasks - Trained end-to-end from scratch Full weights release this month. Learn more about Beam: reflection.ai/beam
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Behrooz Ghorbani retweeted
We built our first model!! Beam is a competitive text-only 501B-A23B MoE, openly released under the Apache 2.0 license It’s been fun scaling the production RL/OPD stack for this over the past year. I’m so proud of the team! We attained exactly what we set out to do and ended up with a stable run on 10K GB300s that produced more than 100M rollouts across ~1M tasks that significantly improved the final performance of the model 👇 many more details in our announcement below :)
Reflection
@reflection_aiOct 5
Introducing Beam: a highly efficient agentic open model with 501B total parameters and 23B active. - Frontier reasoning efficiency - Advances the Western open frontier on coding & agentic tasks - Trained end-to-end from scratch Full weights release this month. Learn more about Beam: reflection.ai/beam
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Behrooz Ghorbani retweeted
I’m joining the OSS team at @reflection_ai! 🙏 My life mission has always been to work on open intelligence but there was always a missing piece in my skills: PyTorch taught me the magic of combining Infra knowledge with applied research @joespeez allowed me to be the dumbest person in the room and I learned more from him in those months than all years of my career. It was a total intern feeling and was the happiest I’ve felt in a while. I was convinced that working on OSS infra and applied research should be my next chapter. I’m very grateful to @MishaLaskin and @real_ioannis to allowing me to be a part of the dream To stronger chai and greater learnings at the frontier!
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Behrooz Ghorbani retweeted
Culture is a moat
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Behrooz Ghorbani retweeted
AGI is in its first stages of take-off. Every country is realizing that AI sovereignty is existential, which requires open models. We’ve signed a deal with Shinsegae Group to build South Korea’s sovereign cloud on a US open model built by Reflection. More to come.
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Behrooz Ghorbani retweeted
Excited to announce that, after finishing my PhD a couple of months ago, I will continue to do *open* science at @reflection_ai on @_ghorbani's new team! And we are still looking for exceptional individuals to join us 😉
Hi friends, after three incredible years at OpenAI I am excited to share that I am starting a new chapter at @reflection_ai, where I will be leading the Science of Scaling team. Our mission is to deepen the scientific understanding of large scale learning and to turn compute into intelligence as efficiently and predictably as possible.
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Behrooz Ghorbani retweeted
Reflection
@reflection_ai18 Dec 2025
Most approaches to “agentic AI” focus on post-training fixes. In this conversation, member of our technical staff, @achowdhery argues the bottleneck is pre-training itself. Drawing on her work on PaLM and early Gemini, she explains why next-token prediction breaks down for long-horizon planning -- and how objectives, attention, and training data must evolve to support true agentic behavior.
Today, we're joined by @achowdhery, member of technical staff at @reflection_ai, to explore the fundamental shifts required to build true agentic AI. While the industry has largely focused on post-training techniques to improve reasoning, Aakanksha draws on her experience leading pre-training efforts for Google’s PaLM and early Gemini models to argue that pre-training itself must be rethought to move beyond static benchmarks. We explore the limitations of next-token prediction for multi-step workflows and examine how attention mechanisms, loss objectives, and training data must evolve to support long-form reasoning and planning. Aakanksha shares insights on the difference between context retrieval and actual reasoning, the importance of "trajectory" training data, and why scaling remains essential for discovering emergent agentic capabilities like error recovery and dynamic tool learning. 🗒️ For the full list of resources for this episode, visit the show notes page: twimlai.com/go/759. 📖 CHAPTERS =============================== 00:00 - Introduction 02:26 - Reflection 04:54 - Limitations of post-training for building agents 07:31 - Rethinking pre-training in agents 10:51 - Scaling 11:27 - Evolving attention mechanisms for agentic capabilities 12:39 - Memory as a tool 14:13 - Loss objectives and training data 15:50 - Fine-tuning loss in agent performance 19:37 - Training data 21:29 - Augmenting dominant training data source 24:11 - Overcoming challenges in training on synthetic data 25:47 - Benchmarks 30:44 - Scaling laws in large models versus small models 33:20 - Long-form versus short-form reasoning 37:57 - Agent’s ability to recover from failure 40:15 - Hallucinations and failure recovery 43:53 - Tool use in agents 46:38 - Coding agents 48:37 - How researchers can contribute to agentic AI
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Behrooz Ghorbani retweeted
2 hrs in and I have almost lost my voice
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