J-lens: Anthropic's New Interpretability Tool for Reading Claude's Inner Thoughts via a 'Global Workspace'
Anthropic proposes J-lens, an interpretability tool that captures the 'verbalizable' representations inside a Transformer, and uses it to show that Claude contains a privileged subspace analogous to the neuroscientific 'global workspace' — a small set of vectors that broadcast, drive reasoning, respond to external steering, and even leak signals during deception and evaluation awareness.