PenEcho (erickong), backed by Moonshot AI · Web Agents

PenEcho

Open-source AI canvas that replaces the chat box with a 20,000 x 20,000 px surface where handwritten equations and sketched diagrams are read and answered in place. v0.7 added interactive HTML widgets and weather/stocks/FX/GitHub data plugins. Runs locally on Node 20.3+ at localhost:3888; AGPL v3 plus separate commercial license, ~1.6k stars.