MCP Limit Tool

A proxy server for MCP (Model Context Protocol) tools with quota management and tool filtering capabilities.

Features

• Quota Management: Set hourly, daily, weekly, monthly, yearly or once usage quotas per MCP tool
• Tool Filtering: Allowlist specific tools that clients can access
• Hot Reload: Dynamically update configurations without restarting the server
• Usage Tracking: Track and persist tool usage across restarts
• Multiple MCP Servers: Manage multiple MCP tool backends through a single proxy

Quick Start

1. Clone the Repository

git clone https://github.com/36bian/mcp-limit-tool.git
cd mcp-limit-tool
go build -o mcp-limit-tool

2. Configure

Edit config/config.json to configure your MCP server connections and quotas:

{
  "app_name": {
    "command": "npx",
    "args": ["-y", "your-mcp-server"],
    "env": {
      "API_KEY": "your-api-key"
    },
    "allowed_tools": ["tool_name_1", "tool_name_2"],
    "rate_limits": {
      "hourly": {"total": 100, "duration": "1h"},
      "daily": {"total": 500, "duration": "24h"},
      "weekly": {"total": 3000, "duration": "7d"},
      "monthly": {"total": 10000, "duration": "30d"},
      "yearly": {"total": 50000, "duration": "1y"},
      "once": {"total": 1000000, "duration": "unlimited"}
    }
  },
  "second_app_name": {}
}

3. Configure IDE (VS Code / Cursor / Trae)

Add the following to your IDE's MCP configuration. The AppName must match the app name defined in config.json:

{
  "mcpServers": {
    "github": {
      "command": "/path/to/mcp-limit-tool",
      "env": {
        "AppName": "github"
      }
    }
  }
}

Note: The AppName env variable must match the key name in config.json (e.g., "github", "exa", "jina").

Hot Reload

The tool supports hot reloading for configuration changes:

• Add/Remove Apps: Modify config.json to add new MCP servers or remove existing ones
• Update Quotas: Change quota configurations in config.json - changes take effect immediately
• Reset Usage: Edit usage.json to manually reset usage counters

The server watches for file changes automatically - no restart required.

Requirements

• Go 1.24+
• Node.js (for npx-based MCP servers)

License

MIT