stdiokey

stdiokey

stdiokey is a Model Context Protocol (MCP) server written in Rust. It provides system utility tools to MCP clients (like Gemini) using the Stdio transport (Standard Input/Output).

This project allows LLMs to safely query local system information such as CPU usage, memory statistics, and disk space.

Features

• MCP Stdio Transport: Communicates via JSON-RPC messages over stdin/stdout.
• Performance: Built with Rust and Tokio for efficiency.
• Direct CLI Mode: Can be run directly from the command line for quick reports.

Tools

The server exposes the following MCP tools:

1. local_system_info: Generates a comprehensive system report.

   • System Name, Kernel, OS Version, Hostname
   • CPU Core Count
   • Memory Usage (Total, Used, Swap)
   • Network Interface Statistics (RX/TX bytes)

2. disk_usage: Lists usage statistics for all mounted disks.

   • Mount Point, File System
   • Used/Total Space
   • Percentage Used

Prerequisites

• Rust (Edition 2024 compatible)
• make (optional, for convenience)

Authentication

This server requires an MCP API Key for security, even when running locally via Stdio. The server will verify the provided key against the "MCP API Key" stored in Google Cloud API Keys (Project ID: 1056842563084).

You can provide the key in two ways:

1. Using the --key argument when starting the server.
2. Setting the MCP_API_KEY environment variable.

The server uses a two-stage verification process:

• It attempts to fetch the valid key using the gcloud CLI (ideal for local development).
• It falls back to the Google Cloud API Keys library using Application Default Credentials (ADC).

Installation & Build

Clone the repository and build the project:

cargo build --release

Usage

1. As an MCP Server (with Gemini)

This project is configured for use with the Gemini CLI. The configuration is located in .gemini/settings.json. Note: You must provide your API key either via args or env:

{
  "mcpServers": {
    "stdiokey": {
      "command": "cargo",
      "args": ["run", "--quiet", "--release", "--", "--key", "YOUR_SECRET_KEY"],
      "env": {
        "RUST_LOG": "info,stdiokey=debug",
        "MCP_API_KEY": "YOUR_SECRET_KEY"
      }
    }
  }
}

2. Direct CLI Usage

You can run the tools directly without an MCP client. These commands will also display the verification status of your API key if provided:

System Info:

make info
# OR
cargo run --quiet -- info --key YOUR_KEY

Disk Usage:

make disk
# OR
cargo run --quiet -- disk

3. Manual MCP Server Run

To start the server manually (it will wait for JSON-RPC input on stdin):

make run KEY=your-secret-key
# OR
export MCP_API_KEY=your-secret-key
cargo run --release

Development

• Check: make check
• Test: make test
• Format: make fmt
• Lint: make clippy