What is In-Distribution

One of the persistent questions in model development is whether reasoning actually involves… reasoning. As in: are we seeing actual logical conclusions, or just better recall of knowledge and patterns from the training set? LLMs are trained on, roughly, the web, which makes answering that question tricky: almost everything shows up in some form. A model that appears to “reason” through a physics problem could just be pattern-matching an irritated Reddit reply it saw during training.

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Anyone got any Veras?

In the heady world of AI progress, context lengths have seen somewhat more languid growth. After rapid progress up to the 100-300k token range, they’ve largely stayed there for frontier models. We now have a couple of 1m token models that appear economically viable1, with Gemini and Sonnet, but Opus 4.5 (for example) stuck with the 200k window of its predecessor.

  1. So many asterisks should go here after this flagrant assertion 

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Everything MoE

There are two really good ways to learn the deep fundamentals of a field. One we could call the Carmack/Ilya method: get an expert to give you a list of the seminal papers, systematically work through them, and in the process develop a deep, grounded intuition. This seems to work. The second is: funny tweets.

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Attention, Compression & Predicting the next token

Language modelling is one of the great ideas in ML: if you train a model to accurately predict the next word in a sequence of text1, you are forcing it to learn a deep structure for human language. Because language is how we map reality, hopefully then you can do many useful things. This turned out to be right!

  1. The idea dates back to Jeff Elman, I think, who showedthat training a network on this objective caused the network to learn grammar categories and other features of English. 

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Bulls in the bazaar

I don’t think even the most perceptive forecaster would have identified a 90s LucasArts video format being a flashpoint for a discussion of the state of the security. We live in an age of generative AI agents rampaging through OSS though, and that seems to be what has happened.

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