Show HN: Whiteboard (YC W26) – An open-source IDE for thoughtful software design

Whiteboard is an open-source desktop app that allows humans and agents to co-design software in a collaborative workspace. It integrates with tools like Claude Code, Codex, and provides features such as a semantic diff viewer, decision log, and code navigation. The app is currently used by companies like Salesforce and Modal, and is available under an MIT license. A hosted web version is planned, but the desktop app remains self-hostable.