Ideas

AI Safety & Mechanistic Interpretability

Research notes and projects on AI safety, evaluations, goal drift, and mechanistic interpretability of model behavior.

Thread Retro 7 parts Updated
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Transformer Circuits Thread Notes

Paper-by-paper notes on Anthropic's Transformer Circuits thread: core claims, methods in plain language, and what the evidence does and doesn't show.

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Notes on A Mathematical Framework for Transformer Circuits

Notes on the 2021 paper that reframes transformers as operations on a shared residual stream: QK/OV circuits, virtual weights, and path decompositions of attention-only models.

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Notes on In-Context Learning and Induction Heads

Notes on induction heads, the training phase change in which they form, and the six-part argument connecting them to in-context learning.

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Notes on Toy Models of Superposition

Notes on how sparse features fit into superposition, the geometry and interference that result, and a toy-model account of memorization and double descent.

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Notes on Towards Monosemanticity and Scaling Monosemanticity

Notes on decomposing MLP activations into interpretable features with sparse autoencoders, from a one-layer transformer to Claude 3 Sonnet.

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Notes on Sparse Crosscoders

Notes on sparse crosscoders: one shared feature dictionary across layers or across models, and what that enables for cross-layer analysis and model diffing.

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Notes on Circuit Tracing and the Biology of a Large Language Model

Notes on cross-layer transcoders, local replacement models, and attribution graphs — and the case-study companion paper on Claude 3.5 Haiku.

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Notes on Tracing Attention Computation Through Feature Interactions

Notes on QK attributions, attention-head loadings, and what feature interactions reveal about why a transformer attends to one token rather than another.