mcproxy

MCP Proxy with tool filtering for Claude Code. Intercepts MCP server requests and filters tools based on configuration to reduce token consumption.

Installation

# Run directly with npx
npx @team-attention/mcproxy <upstream-command>

# Or install globally
npm install -g @team-attention/mcproxy

Usage

Basic Usage

Wrap your MCP server command with mcproxy:

mcproxy npx -y @modelcontextprotocol/server-filesystem /path/to/dir

With Claude Code (.mcp.json)

Configure your .mcp.json to use mcproxy as a wrapper:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": [
        "-y", "@team-attention/mcproxy",
        "--",
        "npx", "-y", "@modelcontextprotocol/server-filesystem", "/path/to/dir"
      ]
    },
    "linear": {
      "command": "npx",
      "args": [
        "-y", "@team-attention/mcproxy",
        "--",
        "npx", "-y", "mcp-remote", "https://mcp.linear.app/mcp",
        "--header", "Authorization: Bearer ${LINEAR_API_KEY}"
      ]
    }
  }
}

Configuration

mcproxy automatically creates a .mcproxy.json file to manage tool settings:

{
  "version": "1.0",
  "servers": {
    "[email protected]": {
      "tools": {
        "list_issues": true,
        "create_issue": true,
        "delete_issue": false
      }
    }
  }
}

• Tools are auto-registered on first use with enabled: true
• Set a tool to false to disable it
• Server key is derived from serverInfo.name@version in MCP initialize response

How It Works

Claude Code <-> mcproxy (stdio) <-> MCP Server (subprocess)
                    |
              .mcproxy.json (tool config)

1. mcproxy intercepts the MCP initialize response to get server name
2. On tools/list response, it filters out disabled tools
3. On tools/call request, it blocks disabled tool calls

Options

--config <path>  Path to workspace root for .mcproxy.json (default: current directory)

Debugging

Set DEBUG=1 to enable verbose logging:

DEBUG=1 mcproxy npx -y @some/mcp-server

License

MIT