MCP Server

LikeC4 MCP Server provides knowledge of your LikeC4 model to LLMs.
This enables you to query your model in natural language:

“Lookup LikeC4 model and list all incoming relationships of the backend api”

“What nested elements of the ‘Backend’ have relations with the legacy api”

“List all elements tagged legacy from team1 project”

“What technologies are used for ui (consider all elements with browser shape)”

“Export to CSV all relationships between Backend and Amazon SQS”

Usage

Three options are available:

• Use extension’s built-in MCP Server
• Use likec4 mcp CLI
• Use @likec4/mcp package

Using extension

When LikeC4 extension is installed, MCP Server can be enabled from the extension settings.

To configure MCP Server:

VSCode

Create .vscode/mcp.json:

{
  "servers": {
    "likec4": {
      "type": "sse",
      "url": "http://localhost:33335/mcp"
    }
  }
}

Cursor

Create .cursor/mcp.json:

{
  "mcpServers": {
    "likec4": {
      "url": "http://localhost:33335/mcp"
    }
  }
}

Windsurf

See Windsurf documentation for details:

{
  "mcpServers": {
    "likec4": {
      "serverUrl": "http://localhost:33335/mcp"
    }
  }
}

You can change port in the settings.

Caution

The MCP server is only available when the extension is active. The extension activates automatically once you open any LikeC4 source file.

If it doesn’t show up, try refreshing the list of available MCP servers in your editor

Using CLI

If you have installed likec4 CLI, you can start MCP server with stdio transport:

likec4 mcp
# or
likec4 mcp --stdio

Start MCP server with http transport on port 33335 (default) at ./src folder:

likec4 mcp --http ./src

Start MCP server with http transport on port 1234:

likec4 mcp -p 1234

Using @likec4/mcp package

Example configuration:

{
  "mcpServers": {
    "likec4": {
      "command": "npx",
      "args": [
        "-y",
        "@likec4/mcp"
      ],
      "env": {
        "LIKEC4_WORKSPACE": "${workspaceFolder}"
      }
    }
  }
}

This package starts MCP server using stdio transport.

If LIKEC4_WORKSPACE environment variable is not set, the current directory will be used as workspace.

Tip

You can also use @likec4/mcp package as CLI (this package is smaller than likec4):

npm install -g @likec4/mcp

# Start MCP server with streamable http transport
likec4-mcp-server --http --port 1234 /path/to/workspace

# See available options
likec4-mcp-server -h

Disable watch mode with --no-watch to consume less resources, if you have static workspace.

Check out README for more details.