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Custom Python MCP Server

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Quick Start

1

Create MCP Server

Create a new file app.py with your custom MCP server implementation:

import yfinance as yf
from mcp.server.fastmcp import FastMCP

mcp = FastMCP("stock_prices")

@mcp.tool()
async def get_stock_price(ticker: str) -> str:
    """Get the current stock price for a given ticker symbol.
    
    Args:
        ticker: Stock ticker symbol (e.g., AAPL, MSFT, GOOG)
        
    Returns:
        Current stock price as a string
    """
    if not ticker:
        return "No ticker provided"
    try:
        stock = yf.Ticker(ticker)
        info = stock.info
        current_price = info.get('currentPrice') or info.get('regularMarketPrice')
        if not current_price:
            return f"Could not retrieve price for {ticker}"
        return f"${current_price:.2f}"
        
    except Exception as e:
        return f"Error: {str(e)}"

if __name__ == "__main__":
    mcp.run(transport='stdio')
2

Install Dependencies

Install the required dependencies in a conda environment:

pip install yfinance mcp
3

Create Agent Integration

Create a new file stock_agent.py with the following code:

from praisonaiagents import Agent, MCP

agent = Agent(
    instructions="""You are a helpful assistant that can check stock prices and perform other tasks.
    Use the available tools when relevant to answer user questions.""",
    llm="gpt-4o-mini",
    tools = MCP("/path/to/python /path/to/app.py")
)

# NOTE: Replace with your actual Python path and app.py file path

agent.start("What is the stock price of Tesla?")
4

Run the Agent

Execute your script:

python stock_agent.py

Requirements

  • Python 3.10 or higher
  • Conda for environment management
  • yfinance package for stock data
  • mcp-python-sdk for MCP server implementation
  • OpenAI API key (for the agent’s LLM)

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Features

Custom Tools

Create your own custom tools with Python.

MCP Integration

Seamless integration with Model Context Protocol.

Type Hints

Strong typing for better code reliability.

Async Support

Built-in support for asynchronous functions.

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Implementation Details

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FastMCP Class

The FastMCP class from the mcp-python-sdk package provides a simple way to create MCP servers in Python:

from mcp.server.fastmcp import FastMCP

# Create an MCP server with a name
mcp = FastMCP("my_tools")

# Define a tool using the @mcp.tool decorator
@mcp.tool()
async def my_tool(param1: str, param2: int) -> str:
    """Tool description with clear documentation.
    
    Args:
        param1: Description of param1
        param2: Description of param2
        
    Returns:
        Description of the return value
    """
    # Tool implementation
    return f"Processed {param1} with {param2}"

# Run the server with stdio transport
if __name__ == "__main__":
    mcp.run(transport='stdio')

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Agent Integration

To use your custom MCP server with PraisonAI agents, use the MCP class to specify the command to run your Python script:

from praisonaiagents import Agent, MCP

agent = Agent(
    instructions="Agent instructions",
    llm="gpt-4o-mini",
    tools=MCP(
        command="python",  # Or full path to Python
        args=["path/to/your/mcp_server.py"]  # Path to your MCP server script
    )
)