Datadef MCP server

This URL is a Model Context Protocol endpoint (Streamable HTTP), not a web page. Connected agents like Claude Code, Cursor, Claude Desktop, Codex or ChatGPT can create, edit, lay out and export Datadef architecture diagrams directly, reading your repository for context. Registry name: io.datadef/mcp.

Connect

Create an API key at datadef.io/settings/mcp. Every account can create one and connecting is free. The tools that run AI generation spend credits from the account balance; listing, reading, exporting and repository status do not. Then:

# Claude Code
claude mcp add --transport http datadef https://datadef.io/mcp --header "Authorization: Bearer YOUR_KEY"

# Any desktop MCP client (stdio bridge)
npx -y mcp-remote https://datadef.io/mcp --header "Authorization: Bearer YOUR_KEY"

Per-client setup for Cursor, VS Code, Claude Desktop and ChatGPT is documented at datadef.io/docs/mcp.

Listing the tools without a key

The handshake and the listings are anonymous. initialize, ping, tools/list, prompts/list and resources/list answer with no credentials, so a client, a directory, or a crawler can read the whole tool surface before a key exists. Only tools/call requires authentication.

curl -s https://datadef.io/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

Tools

36 tools in total: 9 outcome tools and 27 fine-grained canvas tools.

• create_diagram: generate a diagram from a plain-language or code description
• create_blank_diagram, list_diagrams, get_diagram: project management
• edit_diagram plus 27 canvas_* tools: nodes, columns, edges, lineage, groups, geometry, layout, validation
• export_diagram: PNG or JPEG, plus a permanent embed URL for READMEs and docs
• repo_status, repo_refresh: inspect and re-run repository sync, the feature that keeps a diagram and its architecture doc regenerated from a git branch or tag, Terraform repositories included (docs)
• get_design_guide: the design standard generated diagrams follow

Common uses

• "Draw the architecture of this repo" from inside your editor
• Update an existing diagram after a merge, or run repo_refresh on a synced project
• Export an embed link so the diagram lives in a README and stays current

More: repo to diagram · documentation · llms.txt