string-length-server MCP Server

A simple Model Context Protocol (MCP) server that exposes a single tool to count the number of characters in a string.

This is useful because large language models (LLMs) are notoriously bad at counting characters accurately. This server provides a reliable way to get the exact string length.

Features

Tools

• get_string_length
  • Description: Counts the number of characters in a string.
  • Parameters:
    • text (string): The input string to measure.
  • Returns: A JSON object with the character count, e.g. { "length": 42 }.

Development

Install dependencies:

npm install

Build the server:

npm run build

For development with auto-rebuild:

npm run watch

Installation

To use with Claude Desktop, add the server config:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "string-length-server": {
      "command": "/path/to/string-length-server/build/index.js"
    }
  }
}

Replace /path/to/string-length-server/build/index.js with the actual path to your compiled server file.

Debugging

Since MCP servers communicate over stdio, debugging can be challenging. We recommend using the MCP Inspector, which is available as a package script:

npm run inspector

The Inspector will provide a URL to access debugging tools in your browser.

License

MIT