What problem does it solve? Running interpretability experiments on large language models requires deep access to internal activations, and models like Llama-3.1-70B or 405B exceed local GPU capacity. This Skill provides guidance for tracing, patching, and steering neural network internals with nnsight, including remote execution on massive models through NDIF. ## Core Features & Use Cases - Activation Analysis & Patching: Trace any PyTorch model, save hidden states and attention patterns, and patch activations between clean and corrupted prompts to test causal relationships. - Remote Execution via NDIF: Run identical interpretability code on 70B+ models by toggling remote=True, with no local GPU required. - Cross-Prompt Interventions & Steering: Share activations between prompts in a single trace, add steering vectors, and perform logit lens analysis. - Use Case: A researcher wants to find which layer of Llama-3.1-70B encodes factual recall. They use activation patching sweeps remotely via NDIF, comparing logit differences across all layers without owning any GPU hardware. ## Quick Start Ask the AI to help you write an nnsight script that traces a prompt through GPT-2, saves the layer 8 hidden states, and patches them into a corrupted prompt to measure the effect on predictions.