Cartogram MCP server

Status: early-stage, active development. Issues and PRs are welcome.

Remote MCP server (Streamable HTTP + OAuth 2.1/PKCE) that lets an MCP-compatible AI agent (e.g. Claude Code) read and write a user's Cartogram projects and diagrams, subject to the same per-project access grants and read/write/admin scopes the user controls from /settings/integrations in the web app.

Production instance: https://mcp.cartogram.andrewpg.me — point any MCP-compatible client at that URL, it self-registers via Dynamic Client Registration (RFC 7591) and walks the OAuth consent screen from there.

Local development

Requires the Supabase backend running — see the sibling cartogram-supabase repo:

supabase start   # from the cartogram-supabase repo

Then, from this repo:

cp .env.example .env
# fill in SUPABASE_URL / SUPABASE_ANON_KEY / SUPABASE_SERVICE_ROLE_KEY
# from `supabase start`'s output, a random MCP_JWT_SIGNING_SECRET, and
# MCP_FRONTEND_URL (where the frontend's OAuth consent screen lives)
npm install
npm run dev

Related MCP server: Agent Identity MCP Server

Testing

npm test

Tools exposed

Known limitations

• delete_project and remove_collaborator are intentionally not exposed (destructive, low-value for the "document a repo" flow this is built around — add later if there's real demand).

• childDiagram slugs are not validated against existing diagrams at write time — a typo creates a dangling reference instead of failing fast.