Diagrams MCP Server

What the code does

We read the source, 9 min ago · rules 3dff92dd89df

What this server is able to do. For an MCP server this is often the job itself — a terminal server runs commands because that is what it is for. Listed so you know what you are plugging in, not as an accusation.

    const child = spawn(argv[0], argv.slice(1), { stdio: "inherit" });

    : path.join(projectRoot, diagramsDirSetting);

Is this your server and something here is wrong? Tell us — corrections are free and do not require a plan.

Connect this server

This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.

claude mcp add diagrams-mcp-server -- npx -y diagrams-mcp-server

{
  "mcpServers": {
    "diagrams-mcp-server": {
      "args": [
        "-y",
        "diagrams-mcp-server"
      ],
      "command": "npx"
    }
  }
}

[mcp_servers.diagrams-mcp-server]
command = "npx"
args = ["-y", "diagrams-mcp-server"]

{
  "mcpServers": {
    "diagrams-mcp-server": {
      "args": [
        "-y",
        "diagrams-mcp-server"
      ],
      "command": "npx"
    }
  }
}

{
  "mcpServers": {
    "diagrams-mcp-server": {
      "args": [
        "-y",
        "diagrams-mcp-server"
      ],
      "command": "npx"
    }
  }
}

This one needs environment variables set before it will start: PROJECT_ROOT (Project root to attach to (defaults to the working directory).), DIAGRAMS_DIR (Diagrams directory, relative to PROJECT_ROOT unless absolute (default: diagrams).), PLANTUML_SERVER_URL (Override for the opt-in remote PlantUML fallback.), ALLOW_REMOTE_PLANTUML (Set to true to allow the remote PlantUML fallback when no local CLI is installed.), DISABLE_REMOTE_PLANTUML (Set to true to always disable the remote PlantUML fallback.). The author declared them in the registry entry; get the values from the project itself.