What problem does it solve?
Neural network neurons are polysemantic, activating across unrelated contexts due to superposition, which makes understanding what models have learned extremely difficult. This Skill provides a complete workflow for training Sparse Autoencoders (SAEs) that decompose dense activations into sparse, monosemantic features corresponding to interpretable concepts.
Core Features & Use Cases
- Pre-trained SAE Loading: Load and analyze existing SAEs from releases like gpt2-small-res-jb to inspect features without retraining.
- Custom SAE Training: Configure and train SAEs with Standard, Gated, TopK, or JumpReLU architectures using LanguageModelSAERunnerConfig.
- Feature Analysis & Steering: Identify top-activating features per token, perform feature attribution to specific predictions, and steer model outputs by injecting feature directions.
- Use Case: A safety researcher wants to find features in GPT-2 that activate on deceptive or harmful content. They load a pre-trained SAE, encode activations from a curated dataset of prompts, and identify the top features for manual interpretation.
Quick Start
Use the saelens skill to load the gpt2-small-res-jb SAE and identify the top 10 features activating on the prompt 'The capital of France is'.