Mercury-Viewer: A Self-Contained Browser-Based Interactive 3D Visualization of LLM Internal Sensor Maps
Ho Yiing Chen · Zenodo (CERN European Organization for Nuclear Research) · 2026
This record releases Mercury-Viewer, a single HTML file (~2 MB) that opens in any browser and shows the inside of a transformer language model as a 3D point cloud. No install, no server, no GPU, no API key. Mercury-Viewer reads activation data from the Mercury sensor grid and draws it in cylindrical coordinates: azimuth is the hidden dimension index, radius is the activation quantile, height is how many prompts activated a given unit. Every point keeps a full (L, D, Q) coordinate, so hovering reveals the exact location, and the picture is invertible. Alongside the viewer, this record releases the Mercury-3B-7B observation dataset: 21,694 fired-cell records and 28,654 visible Rosen-bridge co-firing edges, captured by running ten multilingual prompts through qwen2.5:3B and qwen2.5:7B on a single RTX 3060. Code MIT, data CC-BY-4.0. The whole pipeline ran in 24 hours on consumer hardware. Live viewer: https://charenix.com/static/neuron-mercury/llm-model.htmlSource code: https://github.com/norika/Neuron-MercuryCompanion papers: Mercury method, discovery, and scaling preprints (forthcoming on Zenodo). © 2026 Chen, Ho Yiing. Released under Creative Commons Attribution 4.0 International (CC-BY-4.0). Permanent archival at Zenodo.