Chain lens: training-free multi-token activation readout beats J-lens 0.42 vs 0.32

voooooogel · x · 2026-11-12

vgel and Raymond Douglas release a draft paper introducing the chain lens, which extends single-token lenses like the J-lens into multi-token readouts via contrastive decoding on an MTP head — no training needed. It scores 0.42 vs 0.32 for J-lens across all 28 WorkspaceBench families, beats a hindsight composite of the best untrained lenses (0.49 vs 0.41), and even surpasses a trained oracle lens on arithmetic chain intermediates (0.42 vs 0.25), though readouts remain fragmentary.

Related event: Chain Lens: Training-Free Multi-Token Readout from Model Activations(6 posts)→

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