Circuits Updates — October 2026 transformer-circuits.pub

Anthropic researchers Kola Ayonrinde and Jack Lindsey introduced the J++ lens, an updated method for reading concepts from a model’s intermediate layers. It fits separate Jacobians to clusters of activations, uses learned weights to downweight noisy clusters, and adds other filtering and relevance-propagation improvements; Anthropic says it more reliably reveals reasoning-related latent variables than the J-lens and R-lens. The team released code, lenses and an interactive Neuronpedia demo.