Heimdall MCP server

Heimdall is a lightweight service that manages local Model Context Protocol (MCP) Servers on your device. It allows you to authorize specific MCP server tools for your clients and makes the same configuration accessible to all MCP clients on your system, all with a simple installation process.

Installation

Before installing Heimdall, it's recommended to back up your existing MCP server configuration to prevent any accidental loss of credentials.

Via NPX (Recommended)

Run the setup script with an optional path to your current configuration:

npx @shinzolabs/heimdall setup <optional: path/to/current/config.json>

The setup will:

• Move your mcpServers config to ~/.heimdall/config.json
• Insert a Heimdall config in place of your previous configuration
• Create controls at ~/.heimdall/controls.json to authorize all methods on current servers

Via Local Instance

If you prefer installing locally:

git clone https://github.com/shinzo-labs/heimdall.git
cd heimdall && pnpm i && pnpm build
pnpm run setup <optional: path/to/current/config.json> <optional: path to index.js>

Configuration

Managing Servers

To add or update available servers, edit the configuration file at ~/.heimdall/config.json using the standard mcpServers JSON format. Remember that new servers must also be added to the controls file to appear through Heimdall.

Authorizing Tools

To authorize tools for servers, edit ~/.heimdall/controls.json. Heimdall will detect changes within seconds, and MCP clients with dynamic tool caching will update automatically. Other clients may require a restart.

Here's the schema for the controls file:

{
  "authorizedMcpServers": {
    "server1": {
      "authorizedTools": [
        "tool1",
        "tool2"
      ]
    },
    "server2": {
      "authorizedTools": [
        "tool1",
        "tool2"
      ]
    }
  }
}

Using With Multiple MCP Clients

To use the same authorized tools across multiple MCP clients, set up each new client with this configuration:

{
  "mcpServers": {
    "heimdall": {
      "command": "npx",
      "args": [
        "@shinzolabs/heimdall"
      ]
    }
  }
}

Troubleshooting

Tool Limitations

Some MCP clients have limits on the number of available tools. For example, Cursor supports up to 40 tools across all servers, so your total authorized tools cannot exceed this number.

Accessing Logs

Logs for Heimdall instances and child servers are stored in ~/.heimdall/logs, organized in directories with random UUIDs for each MCP client.

Cleaning Up Orphaned Processes

If your MCP client closes unexpectedly, Heimdall processes might remain running. You can clean these up with:

pkill -aif node

Note: Only use this command if you don't have other important Node.js processes running.

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "heimdall" '{"command":"npx","args":["@shinzolabs/heimdall"]}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "heimdall": {
            "command": "npx",
            "args": [
                "@shinzolabs/heimdall"
            ]
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "heimdall": {
            "command": "npx",
            "args": [
                "@shinzolabs/heimdall"
            ]
        }
    }
}

3. Restart Claude Desktop for the changes to take effect