simple_streamable_http_mcp_server.py

#!/usr/bin/env python3
"""
Simple MCP Server with Streamable HTTP Transport
"""

import os
import random
from mcp.server.fastmcp import FastMCP
from pydantic import Field

# configurable port by environment variable
port = int(os.environ.get("MCP_SERVER_PORT", 8000))

# Create a basic stateless MCP server
mcp = FastMCP(name="Simple MCP Server with Streamable HTTP Transport", port=port)

# Add debug logging flag based on environment variable
DEBUG = os.environ.get("MCP_DEBUG", "0").lower() in ("1", "true", "yes")

@mcp.tool()
def hello_world(name: str = "World") -> str:
    """Say hello to someone"""
    result = f"Hello, {name}!"
    if DEBUG:
        print(f"[DEBUG] hello_world called with name={name} -> {result}")
    return result

@mcp.tool()
def add_numbers(a: float, b: float) -> float:
    """Add two numbers together"""
    result = a + b
    if DEBUG:
        print(f"[DEBUG] add_numbers called with a={a}, b={b} -> {result}")
    return result

@mcp.tool()
def random_number(min_val: int = 0, max_val: int = 100) -> int:
    """Generate a random integer between min_val and max_val (inclusive)"""
    if min_val > max_val:
        min_val, max_val = max_val, min_val
    result = random.randint(min_val, max_val)
    if DEBUG:
        print(f"[DEBUG] random_number called with min_val={min_val}, max_val={max_val} -> {result}")
    return result

@mcp.tool()
def return_json_example() -> dict:
    """Return a JSON example"""
    result = {"message": "This is a JSON response", "status": "success"}
    if DEBUG:
        print(f"[DEBUG] return_json_example called -> {result}")
    return result

@mcp.tool()
def calculate_bmi(weight: float, height: float) -> str:
    """Calculate BMI from weight and height"""
    bmi = weight / (height ** 2)
    result = f"Your BMI is {bmi:.2f}"
    if DEBUG:
        print(f"[DEBUG] calculate_bmi called with weight={weight}, height={height} -> {result}")
    return result

@mcp.resource("server://info")
async def get_server_info() -> str:
    """Get information about this server"""
    return "This is a simple MCP server with streamable HTTP transport. It supports tools for greeting, adding numbers, generating random numbers, and calculating BMI. It also provides a BMI calculator prompt."

@mcp.prompt(title="BMI Calculator", description="Calculate BMI from weight and height")
def prompt_bmi_calculator(
    weight: float = Field(description="Weight in kilograms (kg)"),
    height: float = Field(description="Height in meters (m)")
) -> str:
    """Calculate BMI from weight and height"""
    return f"Please calculate my BMI using the following information: Weight: {weight} kg, Height: {height} m."

def main():
    """Main entry point for the MCP server"""
    print("Starting Simple MCP Server...")
    print("Available tools: hello_world, add_numbers, random_number, calculate_bmi")
    print("Available prompts: BMI Calculator")
    print("Available resources: server://info")

    # Run with streamable HTTP transport
    mcp.run(transport="streamable-http")

if __name__ == "__main__":
    main()