Text Assist MCP Server

This example MCP server provides basic tools for counting characters and words in a given text. The example shows how MCP servers are built using the Python SDK and demonstrates how MCP server tools are just standard Python functions in an MCP wrapper.

Requirements

• Claude.ai account (MCP support is available for all account types)
• Claude Desktop app, available for macOS and Windows
• uv:
  • macOS via Homebrew:

  brew install uv
  

  • Windows via WinGet:

  winget install --id=astral-sh.uv  -e
  

• A code editor like Visual Studio Code

Installation

uv run

Development

1. Start the virtual environment

   source .venv/bin/activate
   

   NOTE: To stop the virtual environment:

   deactivate
   

2. Run MCP server in dev mode with the MCP Inspector:

   mcp dev server.py
   

Run MCP server in Claude Desktop

1. Open claude_desktop_config.js in an editor:

   File location:

   • MacOS / Linux ~/Library/Application/Support/Claude/claude_desktop_config.json
   • Windows AppData\Claude\claude_desktop_config.json

2. Find the full path to uv:

   • MacOS / Linux:

   which uv
   

   • Windows:

   where uv
   

3. In claude_desktop_config.js

   {
      "mcpServers": {
        "text-assist": {
          "command": "/absolute/path/to/uv",
          "args": [
            "run",
            "--with",
            "mcp[cli]",
            "mcp",
            "run",
            "/absolute/path/to/text-assist/server.py"
          ]
        }
      }
   }
   

4. Reboot Claude Desktop and use a prompt that will trigger your MCP.

Usage

In Claude Desktop, you can:

• Count the total number of characters in a text
• Count characters excluding spaces
• Count words in a text
• Count occurrences of specific letters
• Get a full text analysis including:
  • Total character count
  • Character count without spaces
  • Word count
  • Space count
  • Character frequency distribution