PenEcho

PenEcho transforms how you capture and develop ideas by combining freehand sketching with real-time AI assistance. Draw a question mark, write out a problem, or sketch a diagram—and the AI responds directly on your canvas, maintaining the spatial layout of your thinking process. The tool supports multiple visual themes (Arcane, Sci-fi, Research, Studio) to match your creative mood.

Highlights

• Stylus and mouse support for natural handwriting and freehand drawing
• AI responds contextually on the canvas rather than in a separate chat window
• Handwriting recognition and spatial reasoning for understanding sketches
• Multiple AI backends including Claude, OpenAI, and Kimi
• Plugin system for integrating data (weather, stocks, flowcharts, image search)
• Local snapshot saving and PNG export for sharing or archiving
• Open-source (AGPL v3.0) with optional commercial licensing

PenEcho is designed for anyone who thinks visually—students solving problems, designers ideating, researchers mapping concepts, or anyone who prefers sketching to typing. Whether you're working through math problems, brainstorming visual concepts, or exploring ideas spatially, the tool bridges the gap between natural visual expression and AI capabilities. It's free to use and can be self-hosted or deployed independently.