What problem does it solve? Understanding what individual neurons in transformer feed-forward layers encode is difficult without tooling to extract activations, identify trigger examples, and measure how value vectors align with their keys. ## Core Features & Use Cases - Trigger Example Extraction: Identify the top input examples that activate specific keys (layer/dimension pairs) in transformer FFN layers, with JSONL-to-text conversion for readable inspection. - Prediction Extraction: Extract layer-level and dimension-level FFN predictions into pickle files, with analysis, CSV export, and mode comparison utilities. - Key-Value Agreement Computation: Measure how strongly value vectors correspond to their associated keys, with statistical summaries and per-layer visualization. - Use Case: A mechanistic interpretability researcher studying a WikiText-103 language model can extract trigger examples for specific dimensions, then compute key-value agreement to test whether FFN layers behave as key-value memories. ## Quick Start Run the trigger example extraction script in quick-demo mode against a fairseq transformer checkpoint to extract and inspect trigger examples for sample dimensions.