Connect MCP Servers to Claude Desktop

Claude Desktop is an MCP host: it can connect to many MCP servers simultaneously and expose all their tools inside a conversation. Instead of writing a client script, you register servers once in a config file, restart the app, and Claude can call them on demand.

This lesson shows how to wire up your own servers and a set of community servers through claude_desktop_config.json. Because Claude Desktop launches each server as a subprocess, every server must use the stdio transport.

Servers must use stdio

Claude Desktop starts each server itself and talks to it over standard in/out. So the same math and weather servers from earlier switch to the stdio transport:

# math_server.py
from fastmcp import FastMCP

mcp = FastMCP("Demo 🚀")

@mcp.tool
def add(a: int, b: int) -> int:
    """Add two numbers"""
    return a + b

@mcp.tool
def multiply(a: int, b: int) -> int:
    """Multiply two numbers"""
    return a * b

@mcp.tool
def subtract(a: int, b: int) -> int:
    """Subtract two numbers"""
    return a - b

@mcp.tool
def divide(a: int, b: int) -> float:
    """Divide two numbers"""
    if b == 0:
        return "Error: Division by zero"
    return a / b

if __name__ == "__main__":
    mcp.run(transport="stdio")
    # mcp.run(transport="streamable-http", port=8000)

The weather server is the same code as before, ending in mcp.run(transport="stdio").

Finding the config file

On Windows, paste %APPDATA%\Claude into the File Explorer address bar to open the folder.

Registering your own servers

Each entry under mcpServers gives the server a name plus the command to launch it. Use uv run --directory <abs-path> <script>:

{
  "mcpServers": {
    "weather": {
      "command": "uv",
      "args": [
        "run", "--directory",
        "C:\\Users\\your-username\\projects\\mcp-course\\05 MCP Servers with Claude Desktop",
        "weather_server.py"
      ]
    },
    "math_server": {
      "command": "uv",
      "args": [
        "run", "--directory",
        "C:\\Users\\your-username\\projects\\mcp-course\\05 MCP Servers with Claude Desktop",
        "math_server.py"
      ]
    }
  }
}

After saving, fully quit and reopen Claude Desktop. Your tools appear under the tools (hammer) icon in the chat box, and you can ask things like "What's 12 times 342?" or "What's the weather in Tokyo?"

Adding community servers

The MCP ecosystem ships hundreds of ready-made servers you can add with npx (Node) or uvx (Python). Add any of these alongside your own entries:

{
  "mcpServers": {
    "playwright": {
      "command": "npx",
      "args": ["@playwright/mcp@latest"]
    },
    "airbnb": {
      "command": "npx",
      "args": ["-y", "@openbnb/mcp-server-airbnb", "--ignore-robots-txt"]
    },
    "filesystem": {
      "command": "npx",
      "args": [
        "-y", "@modelcontextprotocol/server-filesystem",
        "C:\\Users\\your-username\\Downloads"
      ]
    },
    "sqlite": {
      "command": "uvx",
      "args": [
        "git+https://github.com/laxmimerit/mcp-server-sqlite.git",
        "--db-path",
        "C:\\Users\\your-username\\Downloads\\employees.db"
      ]
    },
    "excel": {
      "command": "cmd",
      "args": ["/c", "npx", "--yes", "@negokaz/excel-mcp-server"],
      "env": { "EXCEL_MCP_PAGING_CELLS_LIMIT": "4000" }
    },
    "ppt": {
      "command": "uvx",
      "args": ["--from", "office-powerpoint-mcp-server", "ppt_mcp_server"]
    }
  }
}

What each one adds:

• playwright — browser automation (navigate, click, scrape pages).
• airbnb — search Airbnb listings.
• filesystem — read/write files in a folder you allow (here, Downloads).
• sqlite — query a local SQLite database (--db-path points at the file).
• excel — read and write .xlsx workbooks.
• ppt — create and edit PowerPoint decks.

Servers that need secrets

Some servers read credentials from an env block — for example a Notion integration token:

{
  "mcpServers": {
    "notionApi": {
      "command": "npx",
      "args": ["-y", "@notionhq/notion-mcp-server"],
      "env": {
        "NOTION_TOKEN": "your-notion-integration-token"
      }
    }
  }
}

You can also point Claude Desktop at a remote MCP server you have deployed, using the mcp-remote bridge:

{
  "mcpServers": {
    "remote-research-server": {
      "command": "npx",
      "args": ["mcp-remote", "http://your-ec2-public-ip:8000/mcp", "--allow-http"]
    }
  }
}

Recap

• Claude Desktop loads servers from claude_desktop_config.json (%APPDATA%\Claude\... on Windows).
• Your servers must run on the stdio transport and are launched with uv run --directory <abs-path> <script>.
• Community servers add huge capability with one npx/uvx entry.
• Restart Claude Desktop after editing, and treat the config file as a secret.

With Excel and PowerPoint servers connected, you can now turn Claude Desktop into a data analyst — see MCP for Data Analysis with Claude Desktop.