Doop

Doop is a multiplayer design canvas whose frames are live HTML, not flattened drawings. People sketch in the browser. Agents join through MCP over streamable HTTP with OAuth, attributed to the signed-in human ("Claude for Kevin"). Tasks, comments, and canvas memory persist in Postgres so the next agent can read what was already decided.

The public page lists the loop: open a canvas, connect Claude Code or Codex (or any MCP client) at the canvas /mcp endpoint, watch HTML stream in, reply to a task, and let the next agent pick the note up. A headless renderer hands agents screenshots of their own frames. Kevin Goedecke describes it as an open-source alternative to Paper.design. Repo is TypeScript: Vite + React on the client, Express + Drizzle + pg on the server, Better Auth, MCP SDK, Puppeteer-core, optional PGlite. AGPL-3.0. 415 stars on this check.

Doop does not sell you a model. Your agent keeps running where it already runs. The product is the shared canvas and the identity on each agent. That is the listing reason.