Composer

Architecture Diagrams automated by your AI Agent

GitHub

Composer demo

Composer logo Composer MCP Server

Give your AI coding agent an architecture canvas.
Design, visualize, and evolve software architecture diagrams - right from your IDE.

npm version MIT License MCP Compatible

Composer is a visual system design tool that lets AI coding agents create and modify interactive architecture diagrams through MCP (Model Context Protocol). Your agent gets tools to add services, databases, queues, and connections, and you get a live canvas at usecomposer.com that updates in real-time.

Your IDE  <-->  MCP Server (this package)  <-->  Composer API  <-->  Your Diagram

Getting Started

Connect your IDE

Claude Code:

claude mcp add --transport http composer https://mcp.usecomposer.com

Cursor — create .cursor/mcp.json in your project root:

{
  "mcpServers": {
    "composer": {
      "type": "http",
      "url": "https://mcp.usecomposer.com"
    }
  }
}

Your browser will open for authorization on first use.

Claude Code 
claude mcp add --transport http composer https://mcp.usecomposer.com
Cursor

Create .cursor/mcp.json in your project root:

{
  "mcpServers": {
    "composer": {
      "type": "http",
      "url": "https://mcp.usecomposer.com"
    }
  }
}
Codex 
codex mcp add composer -- npx -y @usecomposer/mcp --stdio
VS Code (Copilot Chat)

Create .vscode/mcp.json in your project root:

{
  "servers": {
    "composer": {
      "type": "http",
      "url": "https://mcp.usecomposer.com"
    }
  }
}
VS Code (Cline)

Open Cline sidebar > Settings (gear icon) > MCP Servers > Add Remote Server:

{
  "mcpServers": {
    "composer": {
      "type": "http",
      "url": "https://mcp.usecomposer.com"
    }
  }
}
VS Code (Continue)

Add to .continue/config.yaml:

mcpServers:
  - name: composer
    url: https://mcp.usecomposer.com
Windsurf

Add to ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "composer": {
      "serverUrl": "https://mcp.usecomposer.com"
    }
  }
}

Note: Windsurf uses "serverUrl" instead of "url".

OpenCode

Create opencode.json in your project root:

{
  "mcp": {
    "composer": {
      "type": "remote",
      "url": "https://mcp.usecomposer.com"
    }
  }
}

Tools

Diagram Management

ToolDescription
list_diagramsList all your diagrams. Call this first to find which diagram to work on
create_diagramCreate a new diagram and auto-select it for this session
select_diagramSelect which diagram to work on for this session
rename_diagramRename the currently selected diagram

Note: Call list_diagrams then select_diagram (or create_diagram) before using other tools.

Read

ToolDescription
get_graphGet the full architecture diagram - all nodes and edges
get_nodeGet details for a single node including connected edges
search_graphSearch nodes and edges by keyword
get_screenshotGet a PNG thumbnail of the diagram from the last auto-save

Write

ToolDescription
upsert_nodeCreate or update a node (service, database, queue, etc.)
upsert_edgeCreate or update a connection between two nodes
define_apiDefine API endpoints on a backend service node
delete_elementDelete a node or edge from the diagram
link_pathLink a node to a file or folder in your codebase

Plan & Verify

ToolDescription
verify_diagramCheck for issues like missing endpoints or orphaned nodes
plan_importStep-by-step workflow for importing an existing codebase
get_guideReference guide for node types, protocols, and best practices

Node Types

client · frontend · backend · database · cache · queue · storage · external

Edge Protocols

REST · gRPC · GraphQL · WebSocket · TCP · UDP · async · event · internal

Example Prompts

Once connected, try asking your AI agent:

PromptWhat it does
"Import this codebase into Composer"Scans your repo and builds the architecture diagram
"Create a new Composer diagram called Backend Architecture"Creates and auto-selects a new diagram
"Add a Redis cache between the API and the database in Composer"Adds a new node and edges to the diagram
"Add analytics monitoring to the Composer diagram"Adds observability nodes and connections
"Update the APIs I defined in Composer"Refreshes endpoint definitions on backend nodes
"Verify my Composer diagram"Checks for missing endpoints, orphaned nodes, etc.
"Link each Composer node to its source code"Associates diagram nodes with file paths

How It Works

Authentication is handled via OAuth 2.1 — your browser opens for a one-time consent flow, and you're connected. Tool calls are proxied to the Composer API at mcp.usecomposer.com. Your diagram data lives on Composer's servers. The MCP server itself is stateless.

Changes made through MCP are immediately visible on the Composer canvas via real-time WebSocket sync.

Development

git clone https://github.com/olivergrabner/composer-mcp
cd composer-mcp
npm install
npm run dev        # Watch mode (rebuilds on change)
npm run build      # Production build

Links

License

MIT

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