AI Digest.

Marin's 535B Model Trains Fully in Public While Grok Bot's Source Code Leaks

Percy Liang's Marin project kicked off its biggest and most open training run yet, a 535B-A23B model on 18.75T tokens, while a Cursor-shipped Grok Bot build leaked its own source through leftover runtime source maps. Practitioners also pushed lean agent setups, from a 72% browser-tooling speedup to Pi Agent's four-tool minimalism.

Quick Hits

  • @percyliang announced that Marin 535B-A23B started training this week with "the whole process is open": 18.75T tokens across 11 GB200 NVL72 nodes for roughly three months (2.7e24 FLOPs), with post-training to follow. @0xSero calls it "the coolest thing I've seen all week."
  • @b_nnett spotted that Cursor shipped Grok Bot 0.18.0 with runtime source maps enabled and reconstructed the source on GitHub. @LinearUncle reports the system prompts, tool definitions, and model routing are all readable, and says the newest build already strips the maps.
  • @jun_song says Xiaomi unveiled local inference hardware running a 120B and a 3B model simultaneously on its new O3, O100, and D100 chips, and argues Chinese hardware makers are betting big on open weights and local inference.
  • @dhh says @SpencerGBull's OmaPilot plugin, which runs a local Qwen 27B model, will ship in Omarchy 4.1 as the "fully agentic OS" play.
  • @tobi implemented Cursor's "Git at Scale" blog architecture as a single open-source Rust binary over a weekend, pointed at any S3-style object store; @JorgeO claims it "scales better than GitHub," which is his characterization, not a benchmarked fact.

One Frontier Run Trains in the Open, Another Stays Deliberately Vague

The contrast in model news is stark. On one end, @percyliang laid out the full "voyage plan" for Marin 535B-A23B: 80% pretraining and 20% midtraining on 18.75T tokens, running about three months on 11 GB200 NVL72 nodes for 2.7e24 FLOPs. Before the hero run, the team trained a four-rung scaling ladder from 1.6B-A61M on 48B tokens up to 27.7B-A1.2B on 926B tokens, both to debug issues and to forecast the big run. He concedes it is "by far our biggest run" and they are "definitely expecting the unexpected." @0xero's bookmark note, from @0xSero, highlights the key point: the full training process is public and live.

On the other end, @martin_casado tweeted that he is "mind blown from a new model I just got access to" and thinks it may be "the most significant drop this year," with zero specifics. @mark_k speculates it could be a stronger LLM or even a world model, but that is pure guessing from two vague posts.

Grok Bot's Source Leaks Through Leftover Source Maps

@b_nnett found that "the Cursor team shipped Grok bot (0.18.0) with runtime source maps enabled" and was "surprised nobody noticed until now," posting a reconstructed version with downloads on GitHub. @LinearUncle, amplifying it in Chinese, calls this a rare chance to study a production agent's internals, with system prompts, tool definitions, and model routing logic all readable. His practical warning: move fast, because in his own testing the latest version no longer ships source maps. Two caveats worth holding onto: this reflects one shipped build, and "reconstructed" code should be read skeptically until you inspect it yourself. Still, for anyone studying how a commercial agent harness actually routes between models, it is an unusual window.

Local Inference Gets Dedicated Hardware and an OS Story

The local-compute thread ran through three posts. @op7418 reported (in Chinese) that Xiaomi announced a local AI host built on three new chips, the O3, O100, and D100, supporting dual 120B and 3B models with fast/slow system switching. @jun_song reads it as evidence that Chinese hardware makers see open weights and local inference as the future and are betting accordingly.

On the software side, @SpencerGBull released the first alpha of OmaPilot, an agent plugin for Omarchy Linux, and is recruiting testers to "iron out the Omarchy harness." @dhh enthusiastically confirmed it runs off a local Qwen 27B model and that a version ships in Omarchy 4.1. Rounding out the Omarchy ecosystem, @OmarchyMac shipped Omarchy Mac Quattro, adding Quickshell theming, Lua-based Hyprland config, full disk encryption, improved Apple Silicon support, Btrfs with Snapper snapshots, and faster one-step installation.

The Lean Agent Stack: Short Prompts, Skills, and a 72% Speedup

@xiaomovps published a profile of Pi Agent's creator, Mario Zechner (@badlogicgames): an Austrian game-framework veteran who built libGDX, sold RoboVM (later shut down by Microsoft), and wrote Pi in two nights in late 2025 as a personal tool with just four default tools (read, write, edit, bash) and a compressed system prompt. Per the profile, his own testing found CLI integrations often cheaper and more stable than MCP, and Pi was later acquired by Armin Ronacher's company Earendil, with Zechner keeping technical direction.

@trevin supplied the day's most actionable confession: his Nous Research Hermes browser tasks felt slow because his config was silently still using the legacy browser_* tools. After switching to the Browser Use 3.0 CLI with a persistent cloud/CDP browser, his local benchmark across a dozen tasks ran 72% faster, and he shares the exact prompt to audit your own setup.

Skills also featured twice. @steveruizok suggests a deceptively simple one: ask an agent to "describe the UX of my application completely," which he says surfaces inconsistencies, bugs, and design errors that never came up before. @FareaNFts lists 17 skills to install on a fresh Hermes setup, arguing "a raw Hermes install is smart. A skilled Hermes setup is unfair." And for running agents away from the desk, @kunchenguid shows SSHHIP 1.24's herdr integration, letting you navigate agent sessions from your phone via a command dial, because "mobile keyboard is the worst."

Reading List: Context Layers, Eval Granularity, and an RL Syllabus

@sachinrekhi argues the highest-leverage AI productivity move is not chasing model releases but building a "Compounding OS," or company brain: standardize on an agentic platform, build a shared org-wide skill library, and make all company context machine-legible. @prukalpa endorses it and describes speaking about Atlan's version of this at an AI engineer event.

@realmadhuguru's eval series reached part 7 with a Goldilocks principle: evaluate the intermediate jobs, not just the final answer. His financial-agent example shows stage-level scores (client understanding at 92%, data analysis at 70%) pointing you to exactly where to dig.

For skill-building, @AndrewYNg posted an AI Engineering Skills Map for building and deploying AI applications, which @hi_ZachParent likes as a starting point for FDE-style technical skillsets while noting it omits deciding what is worth building and scoping with clients. @cwolferesearch is publishing a complete guide to RL for LLMs, synthesizing the RLHF Book, Sutton and Barto, OpenAI's Spinning Up, Sebastian Raschka's from-scratch books, John Schulman's notes, Lilian Weng's policy gradient writeup, and more; @loganthorneloe calls the source list a goldmine for LLMs generally.

Lighter links: @Meaningness praises @jon_stokes' essay "Verifiable Domains Will Eat The World" as brilliant at several levels of meta. @vegardstikbakke recommends @hamiltonulmer's interactive post on serving fast dashboards with range requests and Hyparquet. @DeRonin_ calls @frederickjames' "Financial freedom from mobile apps" tutorial the all-in-one article for launching an app. And @pbakaus says one of his less-popular OSS projects gets more personal use than impeccable_ai, after @austriker27 asked who was using it; the project itself goes unnamed in the posts.

Practical Takeaway

The strongest actionable thread is @trevin's: stale agent configs silently tax you, and his move to Browser Use 3.0 CLI cut task time 72% in his own benchmarks. If you run Hermes or any agent with browser tools, paste his audit prompt into a session this week and verify which toolset your config actually loads, then re-benchmark. If your stack still feels heavy afterward, Zechner's CLI-over-MCP finding suggests testing a leaner integration against your real workload before adding another MCP server.

Sources

0
0xSero @0xSero ·
This is the coolest thing I’ve seen all week. Full training process is public and live.
P percyliang @percyliang

🚢 Marin 535B-A23B started training this week! As usual, the whole process is open. Voyage plan: pretraining (80%) + midtraining (20%) on 18.75T tokens on 11 x GB200 NVL72 for ~3 months (2.7e24 FLOPs). Post-training will follow. Before kicking off the run, we trained a 4-rung scaling ladder from 1.6B-A61M (48B tokens) to 27.7B-A1.2B (926B tokens) to debug issues, and to make a forecast of our hero run. This is by far our biggest run, so definitely expecting the unexpected.

O
Omarchy Mac @OmarchyMac ·
Omarchy Mac Quattro is here! - Quickshell + new theming - Lua-based Hyprland config - Full disk encryption - Improved Apple Silicon support - Btrfs + Snapper snapshots - Faster, one step installation 🔗 https://t.co/K3kFSuMtfJ @dhh @tiredkebab @bi9kahuna
D
David Chapman @Meaningness ·
🤖 Absolutely brilliant essay at several levels of meta. Virtuoso performance, tying so many seemingly far-flung themes together as a coherent thesis, with multiple implications for things we care about. https://t.co/5V5KxJPn11
J jon_stokes @jon_stokes

Verifiable Domains Will Eat The World

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Farea @FareaNFts ·
17 Skills I Would Install on a Fresh Hermes Setup (10x Powerful Hack)
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Paul Bakaus @pbakaus ·
this is one of my highly unpopular oss projects that i’m personally using even more often than @impeccable_ai 😅
A austriker27 @austriker27

Anyone using https://t.co/eMB2cBCwsk by @pbakaus ? 👀

L
Logan Thorneloe @loganthorneloe ·
An absolutely goldmine of excellent resources here! Not just for RL, but for LLMs in general. I highly recommend checking out this post (and the resulting article)!
C cwolferesearch @cwolferesearch

Getting ready to publish my complete guide to RL for LLMs tomorrow morning. Although the post contains many of my own thoughts / learnings, it is also a synthesis of so many great resources that have been published over the years: - The RLHF Book (https://t.co/n3aUxqWtgS) by @natolambert - Reinforcement Learning by Richard S. Sutton and Andrew G. Barto - Spinning Up in Deep RL (https://t.co/EYcOOllvIy) from OpenAI - Build an LLM (https://t.co/6HfXuofVwq) and Reasoning Model (https://t.co/l5uS247A04) from Scratch by @rasbt - Various notes (https://t.co/hpsyAKOnRv) and papers (TRPO, PPO, etc.) from John Schulman - Policy Gradient Algorithms (https://t.co/caNLakSjo5) by Lilian Weng - A Vision Researcher’s Guide to RL (https://t.co/25awrjj5Bd) by @YugeTen - From REINFORCE to Dr. GRPO (https://t.co/M23e3Fl3VZ) by @qingfeng_lan - Async GRPO in the Wild (https://t.co/A5qeYMwcy4) by @yumo_xu - Open RL infrastructure like TRL (https://t.co/TGrrnJ574t) and OpenInstruct (https://t.co/L9pObiUb1c) I highly recommend reading all of them. They’ve truly helped me to learn so much.

P
Prukalpa ✨ @prukalpa ·
This is a great post by @sachinrekhi on creating a company context layer to drive outcomes w AI - highly recommend I spoke about our OS at Atlan at @aiDotEngineer https://t.co/weQgr6CKnm
S sachinrekhi @sachinrekhi

I know everyone is talking about Grok Bot, Instinct, and the latest model releases. But in reality, the highest leverage thing you can do to increase your team's AI productivity is invest in building a team-wide Compounding OS, ie. a company brain. In my latest video & essay, I offer a practical guide on how to do exactly that, covering: - Standardizing your team on an agentic platform - Building a robust shared skill library across your entire org - Making all your company context machine legible If you want to avoid the hype and focus on creating real AI leverage for your team, I'd encourage you to check it out. https://t.co/05MgTGxIBf

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Zach Parent @hi_ZachParent ·
If you’re curious about the technical skillset of an OpenAI FDE, this is a good place to start. Of course, missing from this map so far are the abilities to decide what’s worth building, and scoping with clients. I’m excited to see what else @AndrewYNg has in store!
A AndrewYNg @AndrewYNg

AI Engineering Skills Map: Building and Deploying AI Applications

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Steve Ruiz @steveruizok ·
I'm kind of iffy on "skills discourse" but I think I came up with one so good that its worth sharing. The basic ask is to "describe the UX of my application completely". In doing so, agents will discover inconsistencies, bugs, and design errors that have never come up before https://t.co/p67BC3iOq2
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Madhu Guru @realmadhuguru ·
How to build great evals - part 7. The Goldilocks principle for eval construction. Your evals should measure at the level of the various jobs to be done, not just the final answer. E.g. consider a financial analysis agent. It's ultimate output is a stock recommendation. The most common mistake I see is teams create a golden set of right answers and check if the agent recommended the "right” stock. The problem here is that there are probably a bunch of meaningful jobs that happened before this recommendation. E.g. 1/ Understanding the client: their portfolio, risk tolerance, investment horizon, goals, constraints 2/ Gather evidence: latest data points on the different stock stocks, the sectors, macro environment, Fed policy, recent and upcoming news events 3/ Analyze the data: revenue growth, valuation guidance, growth projections and produce a narrower number of candidate stocks 4/ Make a recommendation: stock ticker name, bid/sell price, timeframe Each of these is a stage and produces an intermittent output. Each of them can (and maybe should have) their own eval so you can diagnose issues. If the final recommendation is wrong, a well designed eval set would tell you: Client understanding : 92%, Evidence extraction : 92%, Data analysis: 70% Recommendation: 75% Now you know where to go dig. And you might go, man the data analysis step is too complex and I need to break it down into a set of jobs to be done, and construct eval sets for them. Not too granular. Not too coarse. Just right. Make your eval set as granular as you need to diagnose and act. Drop your eval questions in the comments and I will answer in future posts. Share this with your teammates! See you tomorrow.
R realmadhuguru @realmadhuguru

How to build great evals - part 6 Hill climbing on evals is just a fancy way of saying: pick a dimension that matters and optimize for it. This could be improving the quality of existing features based on your latest production data on high value user journeys, expanding to adjacent use cases, lowering cost or latency. The actual work boils down to better harnesses and model selection through methods like prompt eng, context eng, memory, post training, deterministic old school code etc. Your failure mode taxonomy (from part 3) is a good compass for where your product struggles and needs some love. E.g. maybe tool calling failures are your most common problem. You dig in and notice you stuff 20 tools in context, when each task really only needs 3-5. hill climbing here involves context eng to give it the right tools at the right stage and iterate until you get it to good. Or take the cost reduction goal.. I’ve written about how I advise launching your product with the best model first. Get the quality as high as you can. Once you know users love the experience, hill climb to get similar quality with a smaller, cheaper, faster model. Same methods - harness, models. The important thing is to have evals that tell you whether you are actually moving in the right direction. More tomorrow. Send this to your teammates! Drop your questions in the comments and I will answer in future posts.

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Trevin Chow @trevin ·
My @NousResearch Hermes browser tasks felt really slow and I was confused because I thought I was using all the latest @browser_use 3.0 CLI etc. Turns out I wasn’t, and embarrassingly my config was still using the old browser tools. Now in my local benchmarks across a dozen tasks, it’s 72% faster ❤️ Want to check your setup? paste this into a session: “Check whether I’m using Browser Use 3.0 CLI that was recently released with a persistent cloud/CDP browser or the legacy `browser_*` tools. Fix the config if needed, restart into a fresh session, and report the speed difference.”
小墨同学 @xiaomovps ·
很多人用 Pi,但未必知道背后这个人。 Pi Agent 的作者叫 Mario Zechner,X 上是 @badlogicgames。奥地利人,以前不是做 AI 的,是做游戏框架的。libGDX 就是他搞出来的,Ingress、杀戮尖塔这些都用过。 后来还做过 RoboVM,公司卖了又被微软关掉,社区反噬那一套他经历过,所以现在特别不愿意自己去融一堆钱当 CEO。 2025 年底他自己折腾了一个极简 coding agent,两晚写出来,本来只给自己用。默认就四个工具:read、write、edit、bash,系统提示词压得很短,其他全靠你自己加。口号也写得很直:There are many agent harnesses, but this one is yours。 后来 Flask 作者 Armin Ronacher 的公司 Earendil 把 Pi 收了,Mario 入股并加入团队。他自己发文标题就叫 I've sold out,写得很坦率:不想再走一遍创业那套高压,家里有小孩,但又希望 Pi 能有人养着别停更。技术方向还是他拍板,核心继续开源。 这人说话冲,bio 写的是 Old man yelling at Claudes。讨厌 Agent 越做越重、提示词越写越长。他自己还专门测过 MCP 和 CLI,结论也和很多人实际感受一样:CLI 往往更省、更稳。 所以 Pi 长成现在这样,不是产品经理堆出来的功能清单,是一个老开源作者按自己脾气做的壳。你喜欢它干净、可改、不绑死模型,基本都能从他这个人身上对上号。 感兴趣的话可以去看他博客 https://t.co/DEJ5r0GRU6,或者直接关注 @badlogicgames。产品号是 @pidotdev。
X xiaomovps @xiaomovps

其实Pi 相关网站不用收藏那么多,只要几个就够了。 官网: https://t.co/DVSGiijmJQ 文档、安装、更新都从这进,不要一上来先搜第三方教程。 Skill 文档: https://t.co/39oolR0Eks 怎么写 SKILL.md、放哪、什么时候加载。重复流程优先写成 Skill,别先上 MCP。 扩展文档: https://t.co/UFBvQymczy 要加命令、拦危险操作、改状态栏才看这个。Skill 是说明书,扩展是改运行时。 包装安装: https://t.co/3GTawkmAyu pi install 怎么用。扩展带系统权限,装之前先看安全说明。 插件市场: https://t.co/GzbGrfmYgT 装包先在这搜,比群里复制命令靠谱。 官方源码 https://t.co/O2Dvpku8Yy 权限拦截、沙箱、subagent 示例都在仓库里。 中文文档: https://t.co/oRw5UKSYxw 英文看着费劲就看这个,快速开始够用。 插件合集: https://t.co/AD9dYWmyfq 还想找插件再翻这个,当目录用。 建议你一定要先实操起来,结合文档一起看。不然收藏再多,有没有什么实际的提升。

K
Kun Chen @kunchenguid ·
latest @theSSHHIP has improved @herdrdev native integration! (and added lots of themes incl. my fav rose pine) you can navigate your agent sessions in herdr from your phone through the signature command dial no typing on the keyboard because mobile keyboard is the worst https://t.co/OHkjH6N3h9
T theSSHHIP @theSSHHIP

SSHHIP 1.24 is now live Choose a built-in terminal theme, including Rosé Pine, and set the font size. · On a herdr session, Agent Map shows workspaces, tabs, and live agent status. · Mosh is now available on every host, with automatic fallback to SSH. https://t.co/1GN5asQrYA

D
DHH @dhh ·
Spencer is delivering on our promise for the fully agentic OS of The Future. This is even running off a local Qwen 27B model! We'll be shipping a version of this in Omarchy 4.1. GET READY TO ACCELERATE! 🤖🚀
S SpencerGBull @SpencerGBull

Using an "Agentic Ready OS" is changing the way I use computers… Today I'm releasing the first alpha of the OmaPilot plugin for @OmarchyLinux and looking for more testers to iron out the Omarchy harness. https://t.co/60cjV8YRsc

L
LinearUncle @LinearUncle ·
🚨突发:Grok Bot 0.18.0 被Bennett 小哥发现打包时未关闭 source maps,原始源代码被他完整逆向还原。 GitHub: https://t.co/WLddIFOmVP 这是研究 Grok Bot 内部实现原理的绝佳机会——系统提示词、工具定义、模型路由逻辑全部可读。 建议感兴趣的尽快学习,最新版本我实测已经没有source maps了。
B b_nnett @b_nnett

The Cursor team shipped Grok bot (0.18.0) with runtime source maps enabled. Surprised nobody noticed until now. Source code reconstructed (and downloads) here: https://t.co/56CPNs2YR6

R
Ronin @DeRonin_ ·
okay, that’s probably the most insightful what i’ve seen for the last months that’s literally all-in-one article you need to launch your own successful app:
F frederickjames @frederickjames

Financial freedom from mobile apps: A tutorial.

J
Jorge Ortiz @JorgeO ·
The Cursor blog post about their system design came out ~5 days ago. The presumably very busy CEO of a $200b company has already written a full implementation, in Rust, that scales better than GitHub. What a time to be alive!
T tobi @tobi

Git at Scale (by cursor) has been one of the most interesting blog posts i've read in a while. It came right when I was frustrated with Shopify's internal git system. As an exercise, I've implemented it over the weekend as open source. It's a single rust binary that you can point at any S3 type object store. It uses WAL and CAS primitives and requires no other data store. It also implements bundle-uri so large git repos (like our mono) are very fast to download as a chain of static bundles. Also comes with basic familiar UX. https://t.co/oEnWK3eIL4

J
Jun Song @jun_song ·
Xiaomi just unveiled personal inference hardware that runs a 120B and a 3B model at the same time. Chinese hardware makers know open weights and local inference are the future, and they are betting big on it.
O op7418 @op7418

小米发了一个 AI 的本地的主机,搭载他们新发布的三个芯片,O3、O100 和 D100,支持 120B 和 3B 双模型,支持快慢系统的切换。 https://t.co/gYIleXbByp

V
Vegard Stikbakke @vegardstikbakke ·
Excellent interactive technical post by @hamiltonulmer about a neat way to serve fast dashboards using range requests and Hyparquet. I'm the friend featured in the post! https://t.co/JPN1sjvt68
M
Mark Kretschmann @mark_k ·
What did Martin see? 👀 Apparently a very impressive AI model of some sort is coming soon, with a major capability jump. It could be just a stronger LLM, or perhaps something different like a world model. What's your guess?
M martin_casado @martin_casado

Mind blown from a new model I just got access to. I think this will be one of the most (the most?) significant drops this year. Excited. And sorry to be annoyingly vague. Just excited.