New frontier models now have hidden thinking. You can catch these right now by finding real live bugs on various fronts. On the left, we have Gemini 3 Pro responding on the chat where it messed up formatting a "think silently", on the right is Opus 4.6's "redacted_thinking".

The Art of Wanting. About the question I see as central in AI ethics, interpretability, and safety. Can an AI take responsibility? I do not think so, but *not* because it's not smart enough. davidbau.com/archives/20...

🔥I am super excited for the official release of an open-source library we've been working on for about a year! 🪄interpreto is an interpretability toolbox for HF language models🤗. In both generation and classification! Why do you need it, and for what? 1/8 (links at the end)

Happy Holidays from NDIF! Our new NNsight version improves performance and enhances vLLM integration, including support for tensor parallelism.

Humans and LLMs think fast and slow. Do SAEs recover slow concepts in LLMs? Not really. Our Temporal Feature Analyzer discovers contextual features in LLMs, that detect event boundaries, parse complex grammar, and represent ICL patterns.

How can a language model find the veggies in a menu? New pre-print where we investigate the internal mechanisms of LLMs when filtering on a list of options. Spoiler: turns out LLMs use strategies surprisingly similar to functional programming (think "filter" from python)! 🧵

Glad that President Beilock has chosen not to get involved in this compact nonsense. president.dartmouth.edu/news/2025/10...

Help me thank the NDIF team for rolling out workbench.ndif.us/ by using it to make your own discoveries inside LLM internals. We should all be looking inside our LLMs. Share the tool! Share what you find! And send the team feedback - bsky.app/profile/ndi...

On the Good Fight podcast w substack.com/@yaschamounk I give a quick but careful primer on how modern AI works. I also chat about our responsibility as machine learning scientists, and what we need to fix to get AI right. Take a listen and reshare - www.persuasion.community/p/david-bau

New YouTube video posted! @wendlerc.bsky.social presents his work using SAEs for diffusion text-to-image models. The authors find interpretable SAE features and demonstrate how these features can alter generated images. Watch here: youtu.be/43NnaqGjArA

What's the right unit of analysis for understanding LLM internals? We explore in our mech interp survey (a major update from our 2024 ms). We’ve added more recent work and more immediately actionable directions for future work. Now published in Computational Linguistics!

Who is going to be at #COLM2025? I want to draw your attention to a COLM paper by my student @sfeucht.bsky.social that has totally changed the way I think and teach about LLM representations. The work is worth knowing. And you can meet Sheridan at COLM, Oct 7! bsky.app/profile/sfe...

Coming soon!!

Announcing a broad expansion of the National Deep Inference Fabric. This could be relevant to your research...