Getting Started

Start here. nnsight lets you look inside a model's forward pass and change what happens in it. You wrap a model you already have, open a with model.trace(...) block, and read or edit any internal value as ordinary Python. The model itself doesn't change, and there are no hooks to register.

Two pages get you running. Installation is pip install nnsight and the optional extras. Quick Start is your first trace end to end: load a model, read a hidden state, edit one, and get the values back out. It uses GPT-2 and runs on CPU, so you can follow along without a GPU.

After that, Features has a page per capability, Tutorials has worked interpretability experiments, and the Walkthrough is the long-form guided tour.

Installation

pip install nnsight, the optional extras, and what to install alongside it.

Quick Start

Load a model, read a hidden state, change one, and get the values back out.