MCP Factory

An MCP server that creates, manages, and tests other MCP servers. Built to work with both Claude Desktop and Claude Code agent teams.

How It Works

MCP Factory is itself an MCP server. When invoked by Claude, it spawns a Claude agent (via @anthropic-ai/claude-agent-sdk) that writes, builds, tests, and installs a new MCP server — all from a natural language description.

Each generated server uses stdio transport, so multiple agent team members can use the same server simultaneously (each spawns its own process).

Tools

Tool	Description
create_mcp	Create a new MCP server from a description. Spawns an agent to write, build, test, and install it.
list_mcps	List all factory-created servers with installation status for both Claude Desktop and Claude Code.
remove_mcp	Remove a server from both configs and delete its directory.
test_mcp	Run the MCP JSON-RPC protocol handshake against an existing server.

Installation

Add to your Claude Code settings (~/.claude/settings.json):

{
  "mcpServers": {
    "mcp-factory": {
      "command": "node",
      "args": ["/path/to/mcpfactory/dist/index.js"]
    }
  }
}

Or to Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "mcp-factory": {
      "command": "node",
      "args": ["/path/to/mcpfactory/dist/index.js"]
    }
  }
}

Building

npm install
npm run build

Creating a Server

Ask Claude to create an MCP server:

"Create an MCP server called weather-lookup that fetches current weather for a city using the OpenWeatherMap API"

The factory will:

1. Scaffold the project in ~/mcpfactory/servers/<name>/
2. Spawn a Claude agent to write the implementation
3. Run npm install and npx tsc to verify compilation
4. Test the server via JSON-RPC protocol handshake
5. Install to both Claude Desktop and Claude Code settings

You can also specify tools explicitly:

{
  "name": "weather-lookup",
  "description": "Fetch current weather data",
  "tools": [
    {
      "name": "get_weather",
      "description": "Get current weather for a city",
      "parameters": {
        "city": { "type": "string", "description": "City name", "required": true }
      }
    }
  ],
  "env_vars": {
    "OPENWEATHERMAP_API_KEY": "your-key-here"
  }
}

Agent Team Support

Created servers are installed to ~/.claude/settings.json under the mcp-factory- prefix, making them available to Claude Code agent teams. Since each server uses stdio transport, every team member spawns its own isolated process — no concurrency issues.

Project Structure

mcpfactory/
  src/
    index.ts              # MCP server entry point (4 tools)
    agent/
      spawn.ts            # Claude agent spawning via SDK
      prompts.ts          # System/user prompt templates
    config/
      desktop-config.ts   # Claude Desktop config management
      claude-code-config.ts  # Claude Code settings management
    tools/
      create-mcp.ts       # Create server handler
      list-mcps.ts        # List servers handler
      remove-mcp.ts       # Remove server handler
      test-mcp.ts         # Test server handler
    testing/
      mcp-tester.ts       # JSON-RPC protocol test runner
  servers/                # Generated MCP servers live here

Generated Server Conventions

Every server created by the factory follows these conventions:

• TypeScript with ES2022 target and Node16 module resolution
• @modelcontextprotocol/sdk for MCP protocol
• zod for input schema validation
• StdioServerTransport for communication
• No console.log (stdout is reserved for JSON-RPC protocol)
• Compiled output in dist/, source in src/