The March 2025 blog post by Anthropic titled "Tracing the thoughts of a large language model"[1] is a great introduction to this research, showing how their language model activates features representing concepts that will eventually get connected at some later point as the output tokens are produced.

The associated paper[2] goes into a lot more detail, and includes interactive features that help illustrate how the model "thinks" ahead of time.

[1] https://www.anthropic.com/research/tracing-thoughts-language...

[2] https://transformer-circuits.pub/2025/attribution-graphs/bio...