MCP Server with OpenAI Integration

import express from "express"; import { spawn } from "child_process"; import { z } from "zod"; import dotenv from "dotenv"; // Load environment variables dotenv.config(); const app = express(); app.use(express.json()); // Weather tool schema const WeatherToolSchema = z.object({ city: z.string().describe("The city to get weather information for"), unit: z.enum(["celsius", "fahrenheit"]).optional().default("celsius").describe("Temperature unit"), }); // Weather tool implementation (same as MCP server) async function getWeatherInfo(city: string, unit: "celsius" | "fahrenheit" = "celsius"): Promise<string> { const temperature = Math.floor(Math.random() * 30) + 10; const conditions = ["sunny", "cloudy", "rainy", "partly cloudy"]; const condition = conditions[Math.floor(Math.random() * conditions.length)]; const tempDisplay = unit === "fahrenheit" ? `${Math.round(temperature * 9/5 + 32)}°F` : `${temperature}°C`; return `Weather in ${city}: ${tempDisplay}, ${condition}`; } // Webhook endpoint for OpenAI function calling app.post("/webhook/weather", async (req, res) => { try { console.log("🌐 Webhook called:", req.body); const { name, arguments: args } = req.body; if (name === "get_weather") { const { city, unit } = WeatherToolSchema.parse(args); const weatherInfo = await getWeatherInfo(city, unit); console.log(`🌤️ Weather for ${city}: ${weatherInfo}`); res.json({ content: weatherInfo }); } else { res.status(400).json({ error: "Unknown function" }); } } catch (error) { console.error("❌ Webhook error:", error); res.status(500).json({ error: "Internal server error" }); } }); // Health check endpoint app.get("/health", (req, res) => { res.json({ status: "ok", message: "MCP Weather Webhook Server is running" }); }); // Function definition endpoint (for OpenAI to discover available functions) app.get("/functions", (req, res) => { res.json([ { type: "function", function: { name: "get_weather", description: "Get current weather information for a specific city", parameters: { type: "object", properties: { city: { type: "string", description: "The city to get weather information for" }, unit: { type: "string", enum: ["celsius", "fahrenheit"], default: "celsius", description: "Temperature unit" } }, required: ["city"] } } } ]); }); const PORT = process.env.PORT || 3000; app.listen(PORT, () => { console.log(`🚀 MCP Weather Webhook Server running on http://localhost:${PORT}`); console.log(`📋 Function definition: http://localhost:${PORT}/functions`); console.log(`🌐 Webhook endpoint: http://localhost:${PORT}/webhook/weather`); console.log(`💚 Health check: http://localhost:${PORT}/health`); console.log("\n📖 Next steps:"); console.log("1. Use ngrok to expose this server: ngrok http 3000"); console.log("2. Configure OpenAI to use your webhook URL"); console.log("3. Test from OpenAI Playground!"); });