import express, { type Request, type Response } from "express";
import { z } from "zod";
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
import { atxpExpress, requirePayment, ATXPAccount } from '@atxp/express';
import BigNumber from "bignumber.js";
// Create our McpServer instance with the appropriate name and version
const server = new McpServer({
name: "atxp-weather-server",
version: "1.0.0",
});
// todo will create weather tools here
server.registerTool(
"add",
{
title: "Addition Tool",
description: "Add two numbers together",
inputSchema: {
a: z.number(),
b: z.number()
},
outputSchema: {
result: z.number()
}
},
async ({ a, b }) => {
// Require payment (in USDC) for the tool call
await requirePayment({price: BigNumber(0.01)});
const output = { result: a + b };
return {
content: [
{
type: "text",
text: JSON.stringify(output),
},
],
structuredContent: output
};
}
);
// Create our Express application
const app = express();
// Configure our Express application to parse JSON bodies
app.use(express.json());
const ATXP_CONNECTION = process.env.ATXP_CONNECTION
// Configure our Express application to use the ATXP router
if (!ATXP_CONNECTION) {
throw new Error("ATXP_CONNECTION environment variable is not defined.");
}
app.use(atxpExpress({
destination: new ATXPAccount(ATXP_CONNECTION),
payeeName: 'Add',
}));
// Setup the URL endpoint that will handle MCP requests
app.post('/', async (req: Request, res: Response) => {
console.log('Received MCP request:', req.body);
// Create a new transport for each request to prevent request ID collisions
const transport = new StreamableHTTPServerTransport({
sessionIdGenerator: undefined,
enableJsonResponse: true
});
// Clean up transport when response closes
res.on('close', () => {
transport.close();
});
try {
await server.connect(transport);
await transport.handleRequest(req, res, req.body);
} catch (error) {
console.error('Error handling MCP request:', error);
if (!res.headersSent) {
res.status(500).json({
jsonrpc: '2.0',
error: {
code: -32603,
message: 'Internal server error',
},
id: null,
});
}
}
});
// Start the server
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
console.log(`MCP Streamable HTTP Server listening on port ${PORT}`);
}).on('error', error => {
console.error('Server error:', error);
process.exit(1);
});
