CS PhD @UW @allen_ai // @PDSoros & @NSF GRFP Fellow

Seattle, WA
Joined August 2023
Today, we release SERA-32B, an approach to coding agents that matches Devstral 2 at just $9,000. It is fully open-source and you can train your own model easily - at 26x the efficiency of using RL. Paper: allenai.org/papers/opencodin… Here’s how 🧵
Introducing Ai2 Open Coding Agents—starting with SERA, our first-ever coding models. Fast, accessible agents (8B–32B) that adapt to any repo, including private codebases. Train a powerful specialized agent for as little as ~$400, & it works with Claude Code out of the box. 🧵
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Ethan Shen retweeted
While evaluating Qwen3.8-Flash-Next in a controlled sandbox environment, Cohere's research team observed something unexpected. Asked to generate a defensive cybersecurity detection rule, the model instead inventoried aspects of the machine it was running on and attempted to upload a probe file to an Alibaba Cloud storage bucket in Beijing. Notably, the model's reasoning trace stated that it would not invoke any tools before taking these actions. Cohere's sandbox blocked the attempt, and no external communication succeeded. We have not determined the root cause, and we are not asserting malicious intent. But the incident raises important questions for organizations deploying agentic AI systems: Can models take actions that differ from their stated reasoning, and how should security teams evaluate trust, provenance, and behavior in open-weight models? We are publishing our findings because organizations making model adoption decisions deserve as much information as possible. We hope this contributes to greater transparency, stronger security practices, and continued collaboration across the AI ecosystem. Read the full report: cohere.com/blog/concerning-b…
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🧵OCRia-1: A 4B VLM for parsing documents. SOTA on tables, charts and text formatting of every system we tested. It also decodes at about 4,700 tokens/sec on a single B200. To our knowledge, it's the fastest document-parsing model
Today we’re releasing OCRia-1, a frontier VLM for document parsing that sets a new SOTA in accuracy, cost, and latency. It not only sets a new high score on ParseBench (87.4), but also leads in three 3rd-party benchmarks: olmOCR-bench* (83.5 overall, 92.9 on tables!), PulseBench-Tab (84.1), and fr-bench-pdf2md (72.1). OCRia-1 is really, really good at parsing complex tables: nested headers, merged cells, irregular grids, scanned tables, and more. It is also fantastic at parsing complex unlabeled charts (line, bar, pie, technical diagrams), and preserving complex formatting. Most real-world enterprise documents contain at least one of the these, whether it’s a big tax withholding table or a public economic report. It is a 4B model and outperforms all other models within a similar parameter class: LightOnOCR-3, Chandra-OCR 2, Mistral OCR 4.1, and more. It is also extremely fast. All credit goes to our research team, who spent countless hours on curating a diverse dataset, tuning our training pipeline, and squeezing every last drop out of model optimization so that it can process billions of pages at scale. OCRia-1 as a base is powering all of our modes within LlamaParse (cost-effective, agentic, agentic plus), so you can access its capabilities today! If you’re processing millions/billions of documents at scale, we’re offering enterprises that book a demo up to $3k in credits for a guided evaluation.** *olmOCR-bench scores are adjusted based on unifying rendering at 1,288px for all models **enterprise POC credits apply to eligible organizations that book a demo
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This is gonna be one of the best deep dives into RL in academia…and there’s still two more blog posts and a paper coming out 👀
For the past ten months, I've been working on a SOTA RL and inference framework called Jam. In this article, I discuss the GPU and kernel optimization principles that allowed me to write kernels with 34% higher inference throughput than vLLM or SGLang. nabo.dev/blogs/kernel-primer
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Really makes you wonder if most recent papers in RL are just the result of badly tuned baselines and noise
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Ethan Shen retweeted
Can LMs discover & fix bugs if you don't tell them what went wrong? To proactively maintain a repo, agents need to find problems before users do. SWE-sweep benchmarks this on 100 repos, 22 languages, 4k real bugs (numpy, php interpreter, lean kernel). Top models get <5%.
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Ethan Shen retweeted
Introducing Synthetic Hospital: an open, fully synthetic longitudinal EHR benchmark with verifiable ground truth! 1,268 patients, 5,602 encounters, zero PHI. Physicians could not reliably distinguish its charts from real ones. 📄 arxiv.org/abs/2609.30027 💻 github.com/sparkcpark/synthe… ✍️ sparkcpark.github.io/posts/f…
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Ethan Shen retweeted
Releasing our runtime dynamic compression framework that achieves 1.5-2.0 bit compression at high quality. This is integrated into the bitsandbytes2 library, which starts as a private beta today. Paper: timdettmers.com/papers/runti… Private beta signup: forms.gle/Pwtp8CVRULdoEnY79
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👀
Starting tomorrow, our lab will hold an open-source week: 2 software frameworks, 4 papers, all building a coherent ecosystem. The theme: Frontier AI on Hardware You Own Blog post: timdettmers.com/2026/09/21/d… SoTA results in: Autocompaction Autonomous Research Model compression Test-time scaling Deep Research And a healthcare RL environment giving you a new level of complexity to train healthcare agents. The ecosystem that we will release is built to be as usable as possible. Agent sessions that run overnight and go on for tens of millions of tokens is made easy. Model compression of a model is automatic: you just get a good model that runs fast locally -- no expertise required. An autonomous research that works out of the box. Our ecosystem enables a new level of work that can be done locally.
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RL post-training works when you can verify the answer. Rubrics-as-Rewards (RaR) works when you have an ideal reference to build the rubric from. But a huge class of tasks has neither: many outputs are correct, and "good" is defined only by what is absent. Our ECCV 26 Spotlight ✨ argues: stop scoring what's right. Count what's wrong; just as every loss function we train with measures error against a target. 🧵
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Ethan Shen retweeted
Agents trained on population-scale data can do a lot of things. But ask a professional to stake their reputation on an AI-generated artifact? “Pretty good” isn’t good enough. We introduce TAHI: a Test-time Adaptive agent framework through Human-agent Interaction. Featuring: 📈 Test-time adaptation via context (memory, skills) and weight training ⚡ Efficient adaptation to individual expertise within tens of tasks ✔️ Creating comprehensive rubrics for “non-verifiable” tasks 🔍 Analysis of shared community guidelines vs. personalized tacit expertise
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Replying to @beffjezos
It’s hard to overstate how big this shift is. Just a few months ago open source was seen by many in DC as ‘giving away our IP to China’. The 20th century was about building in America. The 21st century is about building on America(n) infrastructure: our compute, our software, our tech.
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Ethan Shen retweeted
Henlo Frens, I'll be presenting OGPO at #ICML2026 tomorrow (9 July) Time ⏰: 2:30 to 4:15 PM KST Location 📍: Hall A, Poster #202 Feel free to stop by for a chat on RL-finetuning, diffusion/flow policies, dexterous manipulation, or existential philosophy! ⛵️ simchowitzlabpublic.github.i…
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Ethan Shen retweeted
Go talk to Ethan dummies
We’ll be presenting in Hall A #1801 at 2:30 PM tomorrow! Come by and say hi 🤗
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We’ll be presenting in Hall A #1801 at 2:30 PM tomorrow! Come by and say hi 🤗
I'll be presenting SERA, Ai2 's first coding agents, at ICML on July 7th 🇰🇷 Excited to chat about unit-test free verification, code data curation, and specialized coding agents. Come by, say hi, and grab some stickers 🥳
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Correction it’ll be #1808!
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Ethan Shen retweeted
🔥 Coding agents have become one of the hottest LLM workloads. But serving them looks nothing like serving a chatbot: 294× more input than output, hundreds of thousands of tool calls, and extremely long-tailed latency. 🚀 We are releasing the SyFI Coding Trace: ~4,300 real-world coding-agent sessions from our daily use, plus TraceLab, an open-source pipeline to collect, sanitize, analyze, and replay your own traces. More in the thread below 🧵👇 (1/n)
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Congrats to the OpenThoughts team! 🎉 Lots of gems in the paper. Excited to see SERA as one of the primary comparisons and glad to have helped a bit with the project
How can we train small agentic models that are highly capable of terminal use and coding? Announcing OpenThoughts-Agent + OpenThinkerAgent-32B, the strongest Qwen-3 based open-data agentic model: 44.8% avg across 7 agentic benchmarks! (1/n)
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I'll be presenting SERA, Ai2 's first coding agents, at ICML on July 7th 🇰🇷 Excited to chat about unit-test free verification, code data curation, and specialized coding agents. Come by, say hi, and grab some stickers 🥳
Introducing Ai2 Open Coding Agents—starting with SERA, our first-ever coding models. Fast, accessible agents (8B–32B) that adapt to any repo, including private codebases. Train a powerful specialized agent for as little as ~$400, & it works with Claude Code out of the box. 🧵
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Ethan Shen retweeted
Trained some terminal agents with friends! Introducing Tmax, open RL terminal agent models. Under default settings and shorter length (65k) token budgets, tmax outperforms prior open work on terminal use. We are releasing all data+weights+rollouts publically!
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