What is Mcprax

mcprax (pronounced ‘mcp-racks’) is a powerful CLI tool for managing Model Context Protocol (MCP) servers in Claude Desktop. It enables users to define multiple server configurations, group them into ‘racks’, and easily switch between these configurations.

Use cases

Use cases for mcprax include creating development environments with specific server setups, managing different configurations for testing and production, and simplifying the deployment process of MCP servers in various projects.

How to use

To use mcprax, install it globally via npm with the command ‘npm install -g @ownlytics/mcprax’. After installation, you can create racks, add MCP servers, set an active rack, and apply configurations to Claude Desktop using commands like ‘rax create’, ‘rax server create’, ‘rax use’, and ‘rax apply’.

Key features

Key features of mcprax include the ability to define multiple MCP server configurations, group servers into configurable ‘racks’, switch between different racks seamlessly, and apply these configurations directly to Claude Desktop.

Where to use

mcprax is primarily used in software development environments where Model Context Protocol servers are needed. It is particularly useful for developers working with Claude Desktop who require efficient management of multiple server configurations.

mcprax - Model Context Protocol Rack Manager

A powerful CLI tool for managing and deploying Model Context Protocol (MCP) servers to Claude Desktop as configurable “racks” - streamlining your development workflow.

Installation

Install globally via npm:

npm install -g @ownlytics/mcprax

This will make the rax command available globally.

What is mcprax?

mcprax (pronounced “mcp-racks”) is a specialized tool for managing Model Context Protocol (MCP) servers in Claude Desktop. It allows you to:

1. Define multiple MCP server configurations
2. Group these servers into “racks” (collections)
3. Switch between different racks
4. Apply rack configurations to Claude Desktop

This approach is similar to version managers like nvm, rvm, and conda, allowing you to maintain multiple server configurations and easily switch between them.

Quick Start

# Create a new rack for development
rax create ai-tools-rack

# Create an MCP server for filesystem access
rax server create filesystem '{"command": "npx", "args": ["-y", "@modelcontextprotocol/server-filesystem", "/Users/username/Documents", "/Users/username/Projects"]}'

# Create a GitHub MCP server
rax server create github-server '{"command": "npx", "args": ["-y", "@modelcontextprotocol/server-github"], "env": {"GITHUB_PERSONAL_ACCESS_TOKEN": "your-token-here"}}'

# Set the rack as active
rax use ai-tools-rack

# Mount servers to the active rack
rax mount filesystem
rax mount github-server

# Apply the rack to Claude Desktop
rax apply

# Verify your configuration
rax mounted

Commands

Rack Management

• rax create <rackname> - Create a new, empty rack
• rax use <rackname> - Activate a specific rack
• rax list - List available racks
• rax current - Show currently active rack
• rax delete <rackname> - Delete a rack

Server Management

• rax server create <servername> [config] - Create a new server configuration
  • config can be a JSON string, path to JSON file, or command + args
• rax server list - List available servers
• rax server show <servername> - Show details of a server configuration
• rax server delete <servername> - Delete a server configuration

Rack-Server Operations

• rax mount <servername> - Add server to active rack
• rax unmount <servername> - Remove server from active rack
• rax mounted - List servers in the active rack

Configuration Application

• rax apply - Apply active rack to Claude Desktop configuration
  • Use --force to apply even if rack has no servers
  • Use --yes to skip confirmation prompts
  • Use --restart to automatically restart Claude Desktop after applying

Application Management

• rax reboot - Restart Claude Desktop application
  • Use --force to skip confirmation prompt

Version Management

• rax version - Display version information
  • Use --check to check for updates
• rax update - Check for and apply updates to mcprax
  • Use --check-only to only check for updates, don’t install
  • Use --force to update even if already on latest version
  • Use --enable-notifications to enable update notifications
  • Use --disable-notifications to disable update notifications

MCP Server Configuration

MCP (Model Context Protocol) servers allow AI systems like Claude to interact with external tools, data sources, and services through a standardized interface. mcprax helps you manage these server configurations for Claude Desktop.

Server Configuration Format

{
  "name": "github-server",
  "command": "npx",
  "args": [
    "-y",
    "@modelcontextprotocol/server-github"
  ],
  "env": {
    "GITHUB_PERSONAL_ACCESS_TOKEN": "your-token-here"
  },
  "disabled": false,
  "alwaysAllow": [
    "fetch",
    "readFile"
  ]
}

Configuration Fields

• name - Identifier for the server
• command - The executable to run (npx, node, python, etc.)
• args - Array of command-line arguments
• env - Environment variables to set
• disabled - Whether the server is disabled by default
• alwaysAllow - Array of operations to always allow for this server

Creating Server Configurations

There are multiple ways to create a server configuration:

Using JSON directly

rax server create postgres-server '{"command": "npx", "args": ["-y", "@modelcontextprotocol/server-postgresql"], "env": {"PGUSER": "user", "PGPASSWORD": "password", "PGDATABASE": "mydb"}}'

Using command arguments

rax server create vector-db npx -y @modelcontextprotocol/server-chroma

Using interactive mode

rax server create custom-server --interactive

From a JSON file

rax server create config-server path/to/server-config.json

Rack Configuration

A rack is a collection of server configurations. When applied, all servers in the rack are configured in Claude Desktop.

{
  "name": "ai-tools-rack",
  "servers": [
    "filesystem",
    "github-server",
    "brave-search"
  ],
  "description": "Development environment with file access, GitHub, and search capabilities"
}

How It Works

mcprax manages:

1. Server configurations (JSON files in ~/.mcprax/servers/)
2. Rack configurations (JSON files in ~/.mcprax/racks/)
3. Active rack tracking
4. Claude Desktop configuration generation

When you run rax apply, mcprax:

1. Reads the active rack configuration
2. Loads all server configurations in the rack
3. Generates a Claude Desktop configuration file with all the server configurations
4. Backs up the existing Claude Desktop configuration (if any)
5. Writes the new configuration to Claude Desktop

Example Workflows

Basic MCP Server Setup

# Create a development rack
rax create mcp-basic

# Create filesystem server for local file access
rax server create filesystem '{"command": "npx", "args": ["-y", "@modelcontextprotocol/server-filesystem", "/Users/username/Documents"]}'

# Activate and configure
rax use mcp-basic
rax mount filesystem
rax apply

Multiple Environment Management

# Create different racks for different purposes
rax create coding-tools
rax create data-analysis
rax create content-creation

# Configure coding tools rack
rax use coding-tools
rax mount github-server
rax mount code-assistant
rax apply

# Later, switch to data analysis tools
rax use data-analysis
rax mount postgres-server
rax mount csv-tools
rax apply

Popular MCP Server Examples

Here are some examples of popular MCP servers you might want to configure:

1. Filesystem - Provides file system access

   rax server create filesystem '{"command": "npx", "args": ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/directory"]}'
   

2. GitHub - Repository and code management

   rax server create github '{"command": "npx", "args": ["-y", "@modelcontextprotocol/server-github"], "env": {"GITHUB_PERSONAL_ACCESS_TOKEN": "your-token"}}'
   

3. PostgreSQL - Database access

   rax server create postgres '{"command": "npx", "args": ["-y", "@modelcontextprotocol/server-postgresql"], "env": {"PGUSER": "user", "PGPASSWORD": "pass", "PGDATABASE": "db", "PGHOST": "localhost"}}'
   

4. Brave Search - Web search capabilities

   rax server create brave-search '{"command": "npx", "args": ["-y", "@modelcontextprotocol/server-brave-search"], "env": {"BRAVE_API_KEY": "your-api-key"}}'
   

5. Memory - Persistent memory for LLMs

   rax server create memory '{"command": "npx", "args": ["-y", "@modelcontextprotocol/server-memory"]}'
   

Storage Locations

mcprax stores configurations in the user’s home directory:

~/.mcprax/
├── active.json            # Tracks active rack
├── servers/               # Server definitions
│   ├── filesystem.json
│   └── github-server.json
└── racks/                 # Rack definitions
    ├── coding-tools.json
    └── data-analysis.json

The Claude Desktop configuration is stored at:

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

Tips and Best Practices

1. Name servers descriptively - Use names that indicate function (e.g., “github-server”, “postgres-db”)
2. Create purpose-specific racks - Create different racks for different workflows
3. Use the --force flag with caution - It will override configurations without confirmation
4. Check mounted servers before applying - Use rax mounted to verify rack contents
5. Use --restart or rax reboot - Use rax apply --restart or rax reboot to restart Claude Desktop after applying changes
6. Keep sensitive information secure - API keys and tokens in MCP server configurations should be protected

Troubleshooting

Common Issues

• “No active rack set” - Run rax use <rackname> to set an active rack
• “Server not found” - Check if the server exists with rax server list
• Configuration not taking effect - Use rax reboot to restart Claude Desktop after applying changes
• Permission issues - Ensure you have write access to the Claude Desktop configuration directory
• MCP server errors - Check Claude Desktop logs for server-specific error messages
• Update failures - If rax update fails, you may need administrator privileges. Try running npm install -g @ownlytics/mcprax manually

Update Management

mcprax includes built-in tools to help you stay up-to-date:

# Check the current version and available updates
rax version --check

# Update to the latest version
rax update

# Disable update notifications
rax update --disable-notifications

# Enable update notifications
rax update --enable-notifications

Configuration Backup

mcprax automatically creates backups of the Claude Desktop configuration before applying changes. Backups are stored in the same directory as the configuration file with a timestamp suffix.

License

MIT