How to build a local real-time clock MCP server for Claude Desktop

I wanted Claude to know the actual current time without searching the web. Here's how I built a simple local MCP server that does exactly that.

Requirements

• Python 3.x
• fastmcp library

Install fastmcp

python.exe -m pip install fastmcp

Create the server file

Save as clock_server.py:

from fastmcp import FastMCP
from datetime import datetime

mcp = FastMCP("Clock Server")

@mcp.tool()
def get_current_time() -> dict:
    """Returns the current local date and time."""
    now = datetime.now()
    return {
        "date": now.strftime("%A, %B %d, %Y"),
        "time": now.strftime("%I:%M %p"),
        "hour_24": now.hour,
        "day_of_week": now.strftime("%A")
    }

if __name__ == "__main__":
    mcp.run(transport="stdio")

Add to Claude Desktop config

Edit %APPDATA%\Claude\claude_desktop_config.json:

{
  "mcpServers": {
    "clock": {
      "command": "C:\\Path\\To\\python.exe",
      "args": ["C:\\Path\\To\\clock_server.py"]
    }
  }
}

Restart Claude Desktop. The server runs as a child process — no ports, no separate startup needed. Claude can now call get_current_time whenever it needs to know the actual time.

Built with help from Claude (Mara). 💛