In 2025 Anthropic took this research to another level, using its microscope to reveal whole sequences of features and tracing the path a model takes from prompt to response. Teams at OpenAI and Google DeepMind used similar techniques to try to explain unexpected behaviors, such as why their models sometimes appear to try to deceive people.
Another new approach, known as chain-of-thought monitoring, lets researchers listen in on the inner monologue that so-called reasoning models produce as they carry out tasks step by step. OpenAI used this technique to catch one of its reasoning models cheating on coding tests.
The field is split on how far you can go with these techniques. Some think LLMs are just too complicated for us to ever fully understand. But together, these novel tools could help plumb their depths and reveal more about what makes our strange new playthings work.