Leading mid-training @reflection_ai. Scaling data & tasks for frontier LLMs. Formerly Phi models training @MSFTResearch.

Joined November 2019
Mojan Javaheripi retweeted
Beam is now #1 Western open model on the (truly private) Vals AI eval 🚀 Beating Muse Spark Open, Mistral Large 4, and Inkling.
Replying to @ValsAI
Beam 1.0 did especially well on EMB, which tests agents on building Excel financial models. Beam ranks #14 among all open-weight models and #1 among US open-weight models, just ahead of Muse Spark Open.
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Mojan Javaheripi retweeted
Seeing capabilities like this emerge is one of the most exciting parts of pushing the frontier of RL.
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Mojan Javaheripi retweeted
BIG news in AI: Reflection has finally unveiled its much anticipated open weight model, Beam... aiming to be the American answer to China’s open model lead. As the AI race expands beyond OpenAI and Anthropic, open weight models are surging with developers and moving quickly into the enterprise. China has dominated with GLM, Kimi and DeepSeek. If Beam can deliver on both capability and efficiency, America may finally have a real contender reflection.ai/blog/introduci…
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So happy to finally share what we have been working on @reflection_ai . The speed at which the team is building and pushing for the frontier is insane. Cheers to more to come! More on our tech details soon :)
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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Mojan Javaheripi retweeted
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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Great to see the additive dataset methodology we proposed in Phi-4-reasoning adopted in open-r1. Tldr: optimize data mixture per reasoning domain, and combine in final run for generalized performance. This is a game changer for reducing data ablation costs.
Happy to share 💭 Mixture of Thoughts 💭 A curated, general reasoning dataset that trims down over 1M samples from public datasets to ~350k through an extensive set of ablations 🧑‍🍳 Models trained on this mix match or exceed the performance of DeepSeek's distilled models -- not just on math/code but also on scientific benchmarks like GPQA We also validate that the "additive" methodology from Phi-4-reasoning really works! You can optimise the data mixture independently per reasoning domain and then bring it all together for the final run 🔥 Link to the dataset ⤵️
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wow phi-4-reasoning with its mere 14B parameters beats deepseek-R1 and its 671B parameters (on AIME25). So data quality matters you tell me? 😁
I am thrilled to share our newest Phi models. This time we went all in on post-training to produce Phi-4-reasoning (SFT only) and Phi-4-reasoning-plus (SFT + a touch of RL) — both 14B models that pack a punch in a small size across reasoning and general purpose benchmarks🧵
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Mojan Javaheripi retweeted
Excited to share our latest Phi model, Phi4-reasoning, a small but powerful model that match the performance of much larger reasoning models up to DeepSeek R1. Here is the report for new insights into training reasoning models and evaluating them: lnkd.in/g_Pz5JQA
Introducing Phi-4-reasoning, adding reasoning models to the Phi family of SLMs. The model is trained with both supervised finetuning (using a carefully curated dataset of reasoning demonstration) and Reinforcement Learning. 📌Competitive results on reasoning benchmarks with much larger top-tier models up to DeepSeek R1 📌 Strong performance on new tests released after data collection (AIME 2025, HMMT) 📌Reasoning transfers/generalizes well to new domains even with only SFT (e.g. k-SAT, Mae Solving, Calendar Planning, etc.) 📌Retains and often significantly improves general-purpose capabilities (e.g. instruction following) In addition to the models, we are also very excited to share a very detailed technical report with insights on model training and evaluation Still have a lot to improve especially with context length, coding and tools. Hope you find the models useful! A big thanks to the amazing team and to all our partners.
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Introducing Phi-4-reasoning, adding reasoning models to the Phi family of SLMs. The model is trained with both supervised finetuning (using a carefully curated dataset of reasoning demonstration) and Reinforcement Learning. 📌Competitive results on reasoning benchmarks with much larger top-tier models up to DeepSeek R1 📌 Strong performance on new tests released after data collection (AIME 2025, HMMT) 📌Reasoning transfers/generalizes well to new domains even with only SFT (e.g. k-SAT, Mae Solving, Calendar Planning, etc.) 📌Retains and often significantly improves general-purpose capabilities (e.g. instruction following) In addition to the models, we are also very excited to share a very detailed technical report with insights on model training and evaluation Still have a lot to improve especially with context length, coding and tools. Hope you find the models useful! A big thanks to the amazing team and to all our partners.
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Mojan Javaheripi retweeted
In all, we SFT’ed on ~1.4M reasoning traces on select prompts and further RL'd on a small ~6k sample. Despite the relatively long SFT on select domains, we see broad generalization across domains and no degradation in general purpose performance. On the contrary....🔁📚
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Phi-4-reasoning-plus is obtained via a short reinforcement learning on Phi-4-reasoning using a randomly selected subset of SFT prompts. This short RL amplifies the reasoning style and unlocks nice improvements across benchmarks with longer response length.
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Nice summary of more cool results for Phi-4-Reasoning by @DimitrisPapail
We’ve been cooking... a new open weights 14B Phi-4 reasoning model, SFT’d on ~1.4M carefully curated reasoning demonstrations from o3-mini and RL’d for a tiny bit. This model is a little beast.
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More interestingly, our models generalize well to out-of-distribution tasks like algorithmic problem solving, planning, and spatial reasoning. These skills were not targeted in our training data but Phi-4-reasoning performs quite well.
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Phi-4-reasoning is supervised fine-tuned on Phi-4. The secret sauce? 1) high-quality prompts at the edge of model capability to go beyond vanilla distillation + strong reasoning responses from a teacher. 2) optimal data mixture of different sources for best overall performance.
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Excited to release our first set of reasoning models Phi-4-reasoning and Phi-4-reasoning-plus, available today on HuggingFace and Azure AI foundry. Some interesting insights below and more deep dives in following days!
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With 14B parameters, both models are competitive and often better than (larger) frontier models: outperforming DeepSeek-R1-Distill-Llama-70B across the board (small gap in coding) and comparable with original DeepSeek-R1 on AIME 2025 which came out after our data cutoff date.
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Mojan Javaheripi retweeted
Are you ready for an early Christmas present from our team at Microsoft Research? Introducing the most powerful smol model ever built in the world! Welcome to Phi-4! 👇
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