Bringing data science back to AI - https://t.co/Zrmp6LRd9c About Me: https://t.co/P6WyeKkyTa
RT Isaac Flath OCR (esp. VLM approaches) often extract 1 page at time, which breaks when cross-page context is needed, which is a lot. Join @barrowjoseph and I as we dive in and discuss this topic, OCR post processing, and the new Miner U Popo paper. https://luma.com/mineru
RT Raindrop "What will my change change?" Our CTO and co-founder @benhylak joined @HamelHusain to share more on testing agents with Raindrop Simulations. Watch the full video: https://www.raindrop.ai/resources/how-to-test-ai-agents-with-simulations/
I’ve known Ajay for a while and he’s doubled down on making tools that help you look at your data for evals Promising new entrant into the eval tools space
building agents is easy getting them to production is hard today we’re launching @neatlogs to fix that
View quoted postRT Lane || Boot.dev Customer support costs are trending to zero due to AI Not because it's automating it all, but because your vibe-coded slop has no customers to support
RT Pamela Fox Nice post by @isaac_flath on how he evaluates OCR models, with custom annotation apps and agent citation checkers. Great examples of the many ways OCR/VLMs can get things wrong too - like oversimplified tables, swapped digits, and ignored watermarks. https://isaacflath.com/writing/document-evals
RT Lane || Boot.dev "My project is done, now I just need to find users" Oooooh, you mean you're -10% done If you built it without users, get ready to start all over again
Marketers: The next wave of founders will be marketers, distribution is the new moat. PMs: Taste is the moat, and its easier than ever to build the wrong thing. Now is the age of the PM. Eng: You need systems thinking and technical chops to solve hard problems and wield agents effectively at scale. Engineers have more leverage than ever. I suspect good people in each discipline will remain valuable and there isn't one role poised to become unicorns en masse. I do think its good to be skilled at more than 1 discipline, but I am not sure any one of these disciplines has a leg up over the others in that regard
RT Eleanor Berger Re @HamelHusain This was one of my tests. A year ago I started trying to get agents to create slides with Excalidraw. Initially it was terrible, then it started improving, and now it works perfectly. Feel the AGI.
Excalidraw for slides is the 🐐 MCP works great & has animations etc. You can create nice visuals that don't feel like over-produced slop
RT Alex Kemper Lots of people asked about this and I don’t think it makes sense to publish as a built-in skill: https://github.com/docwriter-org/plain-writing-skill It’s from @sh_reya — I also * highly recommend * her and @HamelHusain’s evals course
@rockatanescu We have a skill called “plain writing” in our repo that is the single most used skill internally by a factor of 2
View quoted postRecently had the chance to interview @benhylak on how he is thinking about simulations in our AI Evals Course 😁 Simulations are incredibly useful for evals when you do them well. Ben discusses what he learned from implementing simulations for evals at several companies. Some fun topics came up, my favorite being "simulation awareness" - when models know they are in a simulation. Below is a chapter summary: Why input/output tests miss agent failures Replay production traces to see what a change breaks Recreate the data and tools around the agent How agents detect simulations and change their behavior Choose scenarios that test the change you made Check answers, costs, and tool behavior across runs Replay known failures to verify a fix Common mistakes that make simulations misleading Check that the simulation reproduces production behavior When to start using simulations You can also watch this on YT: https://www.youtube.com/watch?v=eLkESCLvvAs
Recently had the chance to interview @benhylak on how he is thinking about simulations in our AI Evals Course 😁 Simulations are incredibly useful for evals when you do them well. Ben discusses what he learned from implementing simulations for evals at several companies. Some fun topics came up, my favorite being "simulation awareness" - when models know they are in a simulation. Below is a chapter summary: 02:02 Why input/output tests miss agent failures 10:59 Replay production traces to see what a change breaks 13:18 Recreate the data and tools around the agent 16:27 How agents detect simulations and change their behavior 20:39 Choose scenarios that test the change you made 22:00 Check answers, costs, and tool behavior across runs 26:43 Replay known failures to verify a fix 31:20 Common mistakes that make simulations misleading 32:20 Check that the simulation reproduces production behavior 37:37 When to start using simulations You can also watch on YT here: https://youtu.be/Y5LxW81SkCY?si=emWgWuhBZp5wK7l7
RT Tibo Your ChatGPT subscription is now also a Devin subscription
You can use any personal ChatGPT plan with Devin Just connect your Go, Plus, or Pro plan to Devin and all GPT model usage will draw down from you plan's quota
View quoted postRT Joe Barrow A while ago I gave a talk w/ @HamelHusain, “How to Choose an OCR Model,” and I just saw it’s available on YouTube! https://youtube.com/watch?v=mSdmMdpfHpI
Q: How do I make the case for investing in evaluations to my team? A: Review real user interactions and show your team the problems you find. Fix them, then show what improved. https://hamel.dev/blog/posts/evals-faq/how-do-i-make-the-case-for-investing-in-evaluations-to-my-team.html
RT Joma Tech Introducing ChatGPT for Dishwashing GPT-6 achieves state-of-the-art results on dishwashing benchmarks for long-running jobs and difficult stains. The Navier–Stokes Millennium Prize Problem is a $1 million challenge about whether the equations describing fluid motion can break down. In this video, I accidentally found a counter-example while trying to optimize my dishwasher. But in reality, OpenAI used 10,000 AI agents to find a proof in 88 hours: https://openai.com/index/navier-stokes-solution/ Parody of the original GPT-6 Astra ad @OpenAI #ChatGPT_Partner #chatgpt Credits: Written and Directed by Joma Co-Writer - Henry Connor Coan IV @coan_henry Production by Dauntlus Studios @dauntlus.studios Producer/Co-Director - Marcus Liew @dauntlus Camera Operator - Amos Lee @amoselijahlee Art Director - Alethea Soo @aletheasoo Art Assistant - Alicia Lim @aliciatkl_ Assistant Editor - GPT-6 Astra Music: Tensions Run High by Soundridemusic https://www.youtube.com/watch?v=Ly9H63SLJJo
RT Lulu Cheng Meservey The evolution of going direct: Distribution was scarce, so the alpha was in building an audience Then every company started posting all the time, and attention became scarce Then attention became exploited with bait and slop, so now credibility is scarce And there are no shortcuts for credibility
RT Charles 🎉 Frye We updated our LLM Engine Advisor with the latest results from @modal Dedicated Endpoints. With just a few clicks and a single CLI command, you can select and deploy a reasonable open-weights inference service. https://modal.com/llm-almanac/advisor
Q: Can I use the same model for both the main task and evaluation? A: Usually, yes. Test whether the judge agrees with human labels on a held-out test set. https://hamel.dev/blog/posts/evals-faq/can-i-use-the-same-model-for-both-the-main-task-and-evaluation.html
RT Stas Bekman TLDR: all top current AI coding agents I tried suck at large-scale concurrent multi-tasking - solution: one agent to rule them all, and sub-agents to do the actual tasks. For the last couple of weeks I have been working on a task that requires testing and fixing dozens of configs with dozens of slow tests each - a large matrix of options, using many resources to parallelize the work. I tried many top coding agents, and they all failed to multi-task no matter what I have tried. They just kept dropping the ball every 20min or so, wasting resources and not helping me to move forward. Planning mode didn't help at all. Finally I think I have a working recipe - I told the agent not to do any work itself and only be the orchestrator and do all the work through sub-agents, things started to finally move along. Hope this helps others who have a similar need.
RT Murshid Muzamil Error analysis on a real document on a very straightforward "typed" document. Perfectly summarizes what challenges an OCR workflow goes through. good one @HamelHusain @isaac_flath 👏 https://youtu.be/UPEzmVR0dJ8?si=sZ4x9GplnHFxWvtp
RT Shreya Shankar We now support prefix sharing in Quail, our open-source AI-SQL engine! In this example tagging 1,772 long agent traces with issue types using qwen3-4b: we compute 3x fewer tokens and the query runs 2.6x faster ⏩👇
Q: Should I use "ready-to-use" evaluation metrics? A: No. It's a bad idea in most situations. https://hamel.dev/blog/posts/evals-faq/should-i-use-ready-to-use-evaluation-metrics.html
Saw this job posting for an "anti-slop" professional writer but the post itself written with a slop cannon. This is peak AI psychosis, someone is so enamored with their own writing they can't even see it
RT Bryan Bischof fka Dr. Donut As time goes on we only add more and more easter eggs to my podcast episodes. https://x.com/i/article/2107511137667575809
Q: Are similarity metrics useful for evaluating LLM outputs? A: Similar wording does not tell you whether an answer works for your application. Check specific failures. Similarity metrics can help with retrieval and output diversity. https://hamel.dev/blog/posts/evals-faq/are-similarity-metrics-bertscore-rouge-etc-useful-for-evaluating-llm-outputs.html
RT Bryan Bischof fka Dr. Donut Huge
We are making Markdown files work natively across Google Drive and Docs. You can now preview .md files in Drive, open them in Docs, edit them, comment on them, and collaborate without converting the file into a Google Doc!
Q: How often should I run my evals? A: Weigh the cost and how saturated the eval is against the business value of catching the error. Read more: https://hamel.dev/blog/posts/evals-faq/how-often-should-i-run-my-evals.html Read all the FAQs here: https://hamel.dev/blog/posts/evals-faq/
RT Ankur Bhatia As the husband to and son of teachers, I'm qualified* to review online courses. I completed @HamelHusain and @sh_reya course on AI Evals (https://evals.info) and recommend it to anyone who cares measuring quality. tl;dr: Look at your data. Often. * https://youtu.be/o7QIVdz_mUg
You have to respect Schmidhuber’s commitment to the bit 🤣 he was just trolling us all along (which is probably the right way to use this site tbh)
I cannot understand this demo video at all. Sadly, it’s visual slop 😭 Not trying to disrespect anyone maybe the feature is cool it’s just what happened to demos humans can understand
You can now mod Claude Code: - Change how it behaves - Customize the UI - Swap in your own features Write one with a few lines of TypeScript, or have Claude build it for you. Mods ship inside plugins, so you install them with /plugin in the CLI or desktop app. A few examples:
View quoted postRT Shreya Shankar One of the biggest requests we get is “how do I prepare for an applied AI evals interview?” No better person to give this talk than Hamel. I have heard this talk and it’s fantastic. Free and available to all
Last open lesson of the year! How to crack the AI Evals Interview! AI Evals are now a part of an increasing number of AI job postings, and you're now more likely to encounter them in interviews. I've helped design quite a few evals interviews, so I know what kinds of traps
Last open lesson of the year! How to crack the AI Evals Interview! AI Evals are now a part of an increasing number of AI job postings, and you're now more likely to encounter them in interviews. I've helped design quite a few evals interviews, so I know what kinds of traps exist, along with nuanced things companies tend to look for. I'll discuss this, as well as how to structure a take home or report to help you think through the problem clearly. Tuesday Oct 6, 8:30am PT. This one assumes some basic evals knowledge. Read this first if you're new to the topic to get the most out of the session: https://hamel.dev/evals-faq Sign up here: https://maven.com/p/07e7c7
When I see this it confuses me. ssh into a computer for god sakes, or use codex remote feature w/ mac mini. Once you have been stuck in "i need to keep my laptop open" more than 3 times, its crazy to keep this insanity going.
WTF is SF Tech Week? Isn’t every week tech week there LMAO
Q: Why do you recommend binary (pass/fail) evaluations instead of 1-5 ratings (Likert scales)? A: Binary labels force clearer thinking and more consistent labeling, and involves significantly lower complexity to operationalize. https://hamel.dev/blog/posts/evals-faq/why-do-you-recommend-binary-passfail-evaluations-instead-of-1-5-ratings-likert-scales.html
RT Gergely Orosz LLM bots are talking in my replies, this site is having a real problem blocking these accounts. Confusingly, a lot of these bots have a blue check Amusing but also depressing
RT Shreya Shankar Really bullish on workload-aware inference! Database systems are of course a crown jewel of exploiting workload knowledge to achieve good performance. now in today's inference era, any system with a declarative interface and budding demand for LLM inference is probably a good candidate for workload-aware inference
@kushbhuwalka Yep! A batch data processing pipeline usually has several LLM operations, and the API approach makes one call per row per operation, with each call served independently. If you know all the requests up front, you can plan the whole job, like reordering requests within an
View quoted postRT Shreya Shankar Have you tried to use a decision model (like Jev) on thousands of rows? Calling an API once per row is a terrible idea for batch work, because it gets no benefit from query planning and sits *extremely* far from optimal performance. With Qwen3-4B on one H100, the speed-of-light (SoL) for one AI filter over 5k movie reviews, or the fastest the GPU could possibly run it, is about...6.6 seconds! No system today comes close, including Quail, our open-source AI-SQL engine 😱 New blog post on how we cost AI-powered filters in Quail (based on SoL estimates), check it out! https://fsdatalab.github.io/blog/ai-filter-cost-estimates/
Are there any humans here 👋? 95% of replies are bots
Q: Should I build automated evaluators for every failure mode I find? A: No. Different types of evaluators have different costs (code vs. LLM judge), which you need to weigh before building an eval. https://hamel.dev/blog/posts/evals-faq/should-i-build-automated-evaluators-for-every-failure-mode-i-find.html
🥰🙏
@HamelHusain thanks @HamelHusain + @isaac_flath! the latest skill does instruct Claude to build a viewer for eval examples. but as you said, it *doesn't* walk the user through the data first. i agree that this can help the user prioritize which evals to write. i'm going to add this. thanks
View quoted postPeople keep asking about this new Auto Eval plugin for Claude this so I wrote a longer post reviewing it. Would love to hear what other people think! If you used it how did it go? Full writeup here: https://hamel.dev/blog/posts/claude-auto-evals/
Claude can now help you build evaluations and hillclimb on them. In this article, we share guidance on eval design & skills that Claude Code can use to improve your applications. https://claude.dev/blog/automating-eval-design-and-hillclimbing/
View quoted postQ: How can I efficiently sample production traces for review? A: Start with broad exploration, then use signals to find likely failures. Keep some random traces in every batch so you can discover new problems. https://hamel.dev/blog/posts/evals-faq/how-can-i-efficiently-sample-production-traces-for-review.html
🤯🤯🤯🤯 10:46 sign in with ChatGPT, which lets people sign into your app and use the tokens they are paying for already.
I'm at OpenAI's DevDay event in San Francisco today - as I have for the past three DevDay events, I'm running a live blog where I'll be posting updates during the keynote, which starts in five minutes https://simonwillison.net/2026/Sep/29/openai-devday-2026-live-blog/
View quoted postThis is the most time-efficient way to get up to speed on what’s launching today. Simon consistently creates so much value
I'm at OpenAI's DevDay event in San Francisco today - as I have for the past three DevDay events, I'm running a live blog where I'll be posting updates during the keynote, which starts in five minutes https://simonwillison.net/2026/Sep/29/openai-devday-2026-live-blog/
View quoted postWow they did it https://huggingface.co/blog/nvidia/kumo-tabular
Who is gonna create general purpose pre trained regression model and call it Rev We already know there is PMF!
View quoted postQ: How can I do AI evals when traces contain sensitive data? A: Four approaches: negotiate access to a defined scope, work with authorized experts, redaction and synthetic data. https://hamel.dev/blog/posts/evals-faq/how-can-i-do-error-analysis-when-production-traces-contain-sensitive-data.html
I guess we know what’s dropping today 👀 from OpenAI
@rileybrown What if the best frontier model in the world powered a product like this. Wouldn’t that be incredible? 😏
View quoted postPut this through its paces yesterday. Some thoughts: The Bad: 1. The workflow creates evals before looking at data, and has you correct its mistakes. I believe you should be looking at data first to inform your understanding and to prioritize what to work on before trying to write evals. 2. It created markdown files for looking at data and asked us to "tell it" which labels were off. You should create your own annotation app instead. You are using coding agents after all (we did this in our livestream)! 3. The evaluators it scoped were too broad, and bundled too many types of failures at once. This can be avoided with looking at the data first. I'm afraid this might steer people in the wrong direction. 4. The workflow put us DEEP into the rabbit hole of a specific eval right away. It also asks "does it look right" at several steps without really giving you enough information to make that determination. I think this will steer people towards the wrong workflow in many cases. The Good: 1. I was impressed by out of the box ability for issue discovery that other auto-eval approaches haven't been able to find! It found issues with human handoff, formatting, voice agents, and more. It's still better to look at your data iteratively with an agent, but this was the strongest performance I've seen with a more "one-shot" issue discovery approach. 2. This is a big improvement in terms of UX from their prior eval plugin thing https://x.com/ClaudeDevs/status/2098500999656923145?s=20 3. The blog post they released conveys thinking that I agree with, such as the importance of looking at data, sampling intelligently, not saturating your own evals, etc. I'm really happy more people are thinking about evals this way. Video of our attempt at using this here: https://x.com/i/broadcasts/1nKOLQOwQEEGR?s=20
Claude can now help you build evaluations and hillclimb on them. In this article, we share guidance on eval design & skills that Claude Code can use to improve your applications. https://claude.dev/blog/automating-eval-design-and-hillclimbing/
View quoted postWe are going through this new evals thing Anthropic released today re: Evals https://x.com/i/broadcasts/1nKOLQOwQEEGR
Success!!! 🥰
Evals have been coming up more and more in my conversations with podcast guests and PM friends. Nearly half of the 25 awesome PM job openings I shared last week ask for experience writing evals. And leading companies keep sharing what investing in evals bought them: — @tryramp
Q: Can I help with evals if I'm not a domain expert? A: Yes, you can help more than you think! Especially in the beginning, where there's often low hanging fruits that can be uncovered through looking at data. https://hamel.dev/blog/posts/evals-faq/can-i-help-with-evals-if-im-not-a-domain-expert.html
Love this
We instituted an official AI Writing Policy at @Clay. Massive thanks to @sophiebits on our engineering team who wrote this. Originally this was just for eng, but other teams found it so helpful we expanded it company-wide. Here are the four guiding principles: 1. You must
RT Varun Anand We instituted an official AI Writing Policy at @Clay. Massive thanks to @sophiebits on our engineering team who wrote this. Originally this was just for eng, but other teams found it so helpful we expanded it company-wide. Here are the four guiding principles: 1. You must stand behind every idea and sentence It is your responsibility to make sure that the entire document is representative of your own thoughts before you share it. 2. Writing is thinking Spending time on the writing process teaches you more about your topic. If you circumvent this process, you will walk away with a poorer understanding of the subject matter. 3. More time should be spent writing a document than consuming it If you generate a document from a short prompt then ask your readers to go through the longer output, you are disrespecting their time. They can talk to ChatGPT themselves if they want to. 4. Longer is not better AI makes it easy to generate long docs, and it loves padding them with sentences that say nothing. If you're producing docs from a short prompt, consider just sharing the prompt. You can read (and borrow) the full policy below. Hopefully we all communicate a bit more clearly now :)
This is an exciting project ya’ll and it’s just getting started! Some impressive performance numbers already! Can’t wait to see what else is going to come out of this lab https://fsdatalab.github.io/
Excited to share Quail, our new open source AI-SQL engine (a collab with Modal)! By planning queries and LLM inference together, it reaches 1B+ input tokens/min on one H100 for one query 😱🚀 AI-powered data operators create a new, interesting inference workload👇
View quoted postQ: Can I use Jev for evals? A: Jev and an LLM judge are both classifiers that you should validate against trusted labels. Read more: https://hamel.dev/blog/posts/evals-faq/can-i-use-jev-for-evals.html Read all the FAQs here: https://hamel.dev/blog/posts/evals-faq/
I know we are all focused on AI agents But a good human agent (w/AI skills + taste + agency) can transform your business much more. There is unreasonable alpha in finding these human agents maybe now more than ever.
RT Charles 🎉 Frye New on the @modal blog: a write-up by me and Shreya on our work to speed up AI-SQL queries - why AI-SQL? why high-throughput inference? - how can we possibly be >10x faster than vLLM? - what does the future of inference engineering look like? Read here: https://modal.com/blog/quail-billion-tpm
Excited to share Quail, our new open source AI-SQL engine (a collab with Modal)! By planning queries and LLM inference together, it reaches 1B+ input tokens/min on one H100 for one query 😱🚀 AI-powered data operators create a new, interesting inference workload👇
View quoted postQ: Should I record problems that aren't the model's fault? A: Yes. Write down anything that makes the product less useful. Decide which problems to fix before investigating root causes. https://hamel.dev/blog/posts/evals-faq/should-i-record-problems-that-arent-the-models-fault.html
RT Shreya Shankar I feel this pain. The corollary here that I’ve noticed: if you send cold emails or messages to me that *aren’t* written or inspired by AI, you are *way* more likely to get a response than in the pre-AI days. In some ways, the bar has never been lower
"Sorry for the delayed response! Middling generative AI has fundamentally altered the strategic balance between offense & defense in the war for our attention, so I have chosen to ignore this messaging channel. Out beyond kino & slop, there is a field. I'll meet you there."
RT Randy Olson I decided to take the research and expert consensus on what makes a data visualization effective and turn it into an open source agent skill that anyone can use. It's called evident-charts and works in Claude Code, Codex, Cursor and more. Really happy with how it turned out!
Q: What is the best approach for generating synthetic data? A: Define the kinds of requests you need to test. Generate combinations of those details first, then turn them into queries and run them through your application. https://hamel.dev/blog/posts/evals-faq/what-is-the-best-approach-for-generating-synthetic-data.html
RT Sebastian Raschka Reasoning from scratch, round number 5! This time, talking about log-probability scoring (also a great fundamental concept for loss functions like cross-entropy in pre-training and distillation) and self-refinement. 00:00 Introduction and inference-time scaling recap 05:02 Loading the pretrained LLM 08:00 Comparing and scoring model answers 10:18 Building a rule-based scorer 17:53 Token probabilities and sequence likelihood 26:47 Computing token probabilities in PyTorch 30:12 Token indexing and shifted targets 37:27 Log probabilities and numerical stability 45:57 Scoring answers with average log probabilities 56:24 How self-refinement works 59:07 Generating critiques and revised answers 1:01:00 Implementing the self-refinement loop 1:05:57 MATH-500 evaluation results 1:07:35 Takeaways and next steps
Codex is down, you have nothing better to do! Come watch us fill out this tier list for AI Engineering techniques with @BEBischof and @isaac_flath https://x.com/i/broadcasts/1pKkOXLYDvAKj
Evals Tier List https://x.com/i/broadcasts/1pKkOXLYDvAKj
Q: How can I make AI outputs easier for people to evaluate? A: Start with the product design. Keep the human in the loop by designing workflows that walk through intermediate outputs. https://hamel.dev/blog/posts/evals-faq/what-if-human-reviewers-approve-ai-outputs-without-checking-them-carefully.html
RT Shreya Shankar Excited to share Quail, our new open source AI-SQL engine (a collab with Modal)! By planning queries and LLM inference together, it reaches 1B+ input tokens/min on one H100 for one query 😱🚀 AI-powered data operators create a new, interesting inference workload👇
RT Randy Olson Evals are no longer a skill issue thanks to @HamelHusain and @sh_reya.
I recommend grabbing these skills that @sh_reya and I created and at the very least doing an /eval-audit of your existing pipeline. We've found that people often find low hanging fruits! https://github.com/ai-evals-course/evals-skills
View quoted postThis is the most valuable free resource we've created on AI Evals 🎉 (not exaggerating!) I organized our public materials into this guide. It allows you to find answers to your eval problems w/o searching aimlessly. Humans: pick the row that sounds like you. Agents: point it at the post The material draw on 60+ hours of office hours from our Evals course, where @sh_reya and I have taught 5k engineers and PMs Evals. We add new material often, with 15 FAQs added in the last two weeks. Recent additions are marked with a "New" badge. You can find all of these and more here: https://hamel.dev/blog/posts/evals-faq/#how-to-use-this-faq
Q: What are AI evals? A: Tests that tell you whether an AI system is doing what you want. Model benchmarks and product evals answer different questions. https://hamel.dev/blog/posts/evals-faq/what-are-llm-evals.html
RT Sam Julien Can confirm @HamelHusain and @sh_reya are the eval GOATs. Took their course last year and it fundamentally changed how I build AI products & platforms. I also cite them in my evals chapter in my O’Reilly book. 10/10 would look at my data again
Evals have been coming up more and more in my conversations with podcast guests and PM friends. Nearly half of the 25 awesome PM job openings I shared last week ask for experience writing evals. And leading companies keep sharing what investing in evals bought them: — @tryramp
RT Shreya Shankar “I used my agent to formally verify my software and it fixed all these bugs” is the new “I asked an LLM judge to fix my LLM output”. The devil is in the details and it is insanely difficult to get the formalisms “right” (eg interpretable, expressive, extensible) for humans and agents to co-create software. Seems that we are in for an entirely new age of learning how to build software
I used Opus 5.5 to formally verify the Claude Agent SDK using Lean. A couple short prompts = 16 PRs fixing various bugs and race conditions. Video attached. TLA+ also works well. I sometimes combine Lean and TLA+ to look for issues around data flow, concurrency, and state mgmt.
View quoted postRT Shreya Shankar Very exciting to see how much this post resonated with the community. The uncomfortable dialectic is that (1) evals are necessary to build good agents, but also (2) agents are extremely helpful (and necessary) for automating tedious parts of the evals lifecycle. Human attention and labeling simply cannot scale up to the high amount of unstructured info that is agents. Unfortunately nobody has cracked the most perfect and efficient workflow to do evals. We share our thoughts on our current iteration in this post!!
Evals have been coming up more and more in my conversations with podcast guests and PM friends. Nearly half of the 25 awesome PM job openings I shared last week ask for experience writing evals. And leading companies keep sharing what investing in evals bought them: — @tryramp
I recommend grabbing these skills that @sh_reya and I created and at the very least doing an /eval-audit of your existing pipeline. We've found that people often find low hanging fruits! https://github.com/ai-evals-course/evals-skills
Pro tip: Install this new evals skill from @HamelHusain and @sh_reya, it'll save you many hours and a lot of mistakes https://github.com/ai-evals-course/evals-skills
Is Slop Dead? (Testing Writing With 5.5 Opus) https://x.com/i/broadcasts/1DxLdZaydPmxm
RT Sarah Bugden Good Read - "Bulding eval systems that improve your AI product" by @HamelHusain and @sh_reya https://www.lennysnewsletter.com/p/building-eval-systems-that-improve
RT Lenny Rachitsky Pro tip: Install this new evals skill from @HamelHusain and @sh_reya, it'll save you many hours and a lot of mistakes https://github.com/ai-evals-course/evals-skills
Evals have been coming up more and more in my conversations with podcast guests and PM friends. Nearly half of the 25 awesome PM job openings I shared last week ask for experience writing evals. And leading companies keep sharing what investing in evals bought them: — @tryramp
Q: What should you do when your "gold" eval dataset becomes stale? A: Use regular error analysis to find new problems. Keep updating your evals as your product and users change. https://hamel.dev/blog/posts/evals-faq/what-should-i-do-when-my-gold-eval-dataset-becomes-stale.html
RT Hamel Husain Re Also fun fact about Lenny's newsletter now that I've written two guest posts there. The quality bar is **insanely high** Lenny rigorously vets each post. These go through many rounds of writing and technical review with world class staff. You have to sweat it out as a writer but its worth it. Posts and ideas get rejected if they don't meet the bar. It's no wonder that Lenny is at the top of the game. Many people over-index on "quantity" but he's shown dedication to quality. There is something to learn if you are a creator/educator in the space. While we are on the topic of Lenny, he is not an overnight success. He has been doing this with a relentless commitment for over a decade 🤯 and the focus pays off. Truly long-term thinking and playing the infinite game on his part.
Re Also fun fact about Lenny's newsletter now that I've written two guest posts there. The quality bar is **insanely high** Lenny rigorously vets each post. These go through many rounds of writing and technical review with world class staff. You have to sweat it out as a writer but its worth it. Posts and ideas get rejected if they don't meet the bar. It's no wonder that Lenny is at the top of the game. Many people over-index on "quantity" but he's shown dedication to quality. There is something to learn if you are a creator/educator in the space. While we are on the topic of Lenny, he is not an overnight success. He has been doing this with a relentless commitment for over a decade 🤯 and the focus pays off. Truly long-term thinking and playing the infinite game on his part.
This post was a labor of love! We’ve distilled thousands of hours of work on AI Evals into a 30 min read + skills you can use to quickly uncover errors in your product. https://substack.com/home/post/p-216168140 BTW in addition to high quality content, Lenny effectively **pays you** in AI credits to subscribe https://www.lennysproductpass.com/ 🤯 It's really good!
Evals have been coming up more and more in my conversations with podcast guests and PM friends. Nearly half of the 25 awesome PM job openings I shared last week ask for experience writing evals. And leading companies keep sharing what investing in evals bought them: — @tryramp
RT Lenny Rachitsky Evals have been coming up more and more in my conversations with podcast guests and PM friends. Nearly half of the 25 awesome PM job openings I shared last week ask for experience writing evals. And leading companies keep sharing what investing in evals bought them: — @tryramp took its automatic receipt collection from 35% to 83% accuracy. — @Shopify shipped an AI workflow builder that's 2.2x faster and 68% cheaper than the frontier-model setup it replaced. — @harvey__ai rebuilt its AI contract reviewer, nearly doubling its internal quality score. — @cursor_ai tuned its Auto Balance routing, with much higher user satisfaction at 41% lower cost. So I asked the 🐐s of evals, @HamelHusain and @sh_reya, to write an advanced sequel to their very popular "Building eval systems that improve your AI product." Drawing on their work with 50+ AI companies, they share the key step most teams skip, what you should (and shouldn't) automate, and a free plugin that lets a coding agent do most of the heavy lifting. Read it here: https://www.lennysnewsletter.com/p/advanced-evals-how-to-find-and-fix
RT Isaac Flath "In practice, this all means that evals and structured experiments are even more important than they are for regular LLM projects." 💯
Put together some notes on Jev and the new category of system one aka decision models https://simonwillison.net/2026/Sep/21/jev/
View quoted postRT Wayde Gilliam In the process of migrating the repo I built at Braintrust for @HamelHusain and @sh_reya's AI evals course (https://github.com/braintrustdata/ai-evals-course-2025) to an all-@pydantic stack: PydanticAI + Logfire + pydantic-evals. Been living in these tools for a while now and the progress on observability and evals is impressive. I'll be blogging and posting findings here as I go, including where I think models like @typesafeai's Jev fit into the end-to-end evals pipeline. Stay tuned ...
RT Shreya Shankar AI-powered operators in SQL are having their day in the sun
Today we're launching prompt_jev(), which brings Jev, a new kind of AI model from @typesafeai, to MotherDuck SQL. Jev makes text classification super fast, dirt cheap, and as easy as prompting an LLM. In our tests, it ran at 50x the speed and 1% the cost of comparable frontier
View quoted postPeople love rage baiting me with comments that it’s not a classifier because it “also produces a confidence score” or it can choose between two options. I’m gonna assume there isn’t brain rot and that it’s just trolling 😬😅 But well played trolls, well played
What’s wrong with calling it a classifier? Its an established term that describes exactly what this is, along with corresponding literature on how to verify, tune, measure it. Jev is very cool and super useful, because of speed, cost, accuracy and ergonomics. But new terms
View quoted postWho is gonna create general purpose pre trained regression model and call it Rev We already know there is PMF!
What’s wrong with calling it a classifier? Its an established term that describes exactly what this is, along with corresponding literature on how to verify, tune, measure it. Jev is very cool and super useful, because of speed, cost, accuracy and ergonomics. But new terms might hurt more than help. What are your thoughts?
Can we agree to call Jev a "Decision Model"? I feel like they buried this in the explainations and docs. Language models output language. Decision models output decisions.
Can you use Jev for Evals? Yes! Remember that a LLM Judge is also classifier*. Make sure to test your classifiers against human labels and don't overfit. Hope this helps! * https://hamel.dev/blog/posts/evals-faq/why-do-you-recommend-binary-passfail-evaluations-instead-of-1-5-ratings-likert-scales.html
Q: What is a trace? A: The complete record of a user session, from the first query to the final response. It includes the tool calls and intermediate steps. https://hamel.dev/blog/posts/evals-faq/what-is-a-trace.html
Finally 🙏
We're adding support for AGENTS.md to Claude Code. Starting today in version 2.1.277, if there is no CLAUDE.md in a folder, Claude will check for and use AGENTS.md. You can toggle this behavior in /config.
View quoted postIf you are a Data Scientist, you have never had more alpha than right now. Data Scientists email me all the time. It is no mistake that I'm focused on evals as a former DS. I talk more about this here: https://www.youtube.com/watch?v=lA4MfpgF91Y
Q: How do you review a trace that is really large? A: Focus on the first upstream failure. Make the relevant evidence easy to inspect, with details reviewers can expand as needed. https://hamel.dev/blog/posts/evals-faq/what-if-the-source-material-is-too-large-for-a-person-to-review.html