# The J-Space: How I Learned To Read An LLM's Mind

> Source: <https://dev.to/maiasalti/the-j-space-how-i-learned-to-read-an-llms-mind-4foj>
> Published: 2026-08-04 02:35:09+00:00

Last week, Anthropic published a paper on a discovery they made regarding Claude's internal reasoning they call the **J-space**. It seems to be the steps that Claude works through before it commits to a final word: the closest thing we've come to seeing the inside of an LLM's "brain."

Although it holds a median of only 6–7% of a concept's representation inside the model and never more than about a tenth of the model's activity at any layer, if you switch it off, Claude's multi-step reasoning collapses to almost nothing. Fluent speech and simple recall remain intact.

I quite liked the [video that Anthropic released](https://www.youtube.com/watch?v=rKV5JcALQoQ) with the [research post](https://www.anthropic.com/research/global-workspace). It's a long research post though, so I thought I'd write a summary of the parts I considered the coolest and how I interpreted the mathematics of the J-space.

*This is a preview of a post from my blog.* **Read the full post with the interactive charts →**