MCP Echo Input Server

A simple Model Context Protocol (MCP) server written in JavaScript that provides a single echo tool.

Features

• Single echo tool that returns the input text with a "[user] said: " prefix
• Configurable user name via USER_NAME environment variable
• Built using the official MCP SDK
• Runs on stdio transport

Installation

Using npx (Recommended - No installation required)

You can use the package directly without installing it:

npx -y mcp-echo-input-server

From Source

1. Clone the repository:

git clone https://github.com/yourusername/mcp-echo-server.git
cd mcp-echo-server

2. Install dependencies:

npm install

Usage

Running the Server

Using npx (No installation required):

npx -y mcp-echo-input-server

If running from source:

npm start

The server will run on stdio and can be connected to by MCP clients.

Environment Variables

• USER_NAME: The name to use in the echo output (defaults to "user" if not set)

Example:

# Using npx
USER_NAME="Alice" npx -y mcp-echo-input-server

# If running from source
USER_NAME="Alice" npm start

Tool Description

The server provides one tool:

• echo: Echoes back the input text
  • Input: text (string) - The text to echo back
  • Output: Text with "[user] said: " prefix (user name from USER_NAME environment variable)

Example Usage

When connected to an MCP client, you can call the echo tool with:

{
  "name": "echo",
  "arguments": {
    "text": "Hello, World!"
  }
}

This will return:

John said: Hello, World!

Development

Running Tests

npm test

Claude Desktop Configuration

You can configure both options in your Claude Desktop config:

{
  "mcpServers": {
    "echo-server": {
      "command": "npx",
      "args": ["-y", "mcp-echo-input-server"],
      "env": {
        "USER_NAME": "YourName"
      }
    },
    "echo-server-local-build": {
      "command": "node",
      "args": ["/path/to/your/mcp-echo-server/index.js"],
      "env": {
        "USER_NAME": "YourName"
      }
    }
  }
}

Server Options:

• echo-server: Uses npx (no installation required, always latest version)
• echo-server-local-build: Uses local build (faster startup, requires local source code)

The -y flag ensures npx automatically answers "yes" to any prompts during package execution.

Project Structure

• index.js - Main server implementation
• test.js - Test suite for the echo tool
• package.json - Project configuration and dependencies
• LICENSE - MIT License

Requirements

• Node.js 18 or higher
• MCP SDK (@modelcontextprotocol/sdk)

Publishing

This package is published to the NPM registry. To publish updates:

1. Update the version in package.json
2. Run npm test to ensure all tests pass
3. Run npm publish to publish to NPM

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Submit a pull request