import { PingRequestSchema } from '@modelcontextprotocol/sdk/types.js';
import { NextFunction, Request, Response } from 'express';
/**
* Validate MCP protocol version
*/
export function validateProtocolVersion(req: Request, res: Response, next: NextFunction): void {
const version = req.headers['mcp-protocol-version'];
// If no version header, continue (backwards compatibility)
if (!version) {
next();
return;
}
// Check supported versions
const supportedVersions = ['2025-06-18', '2025-03-26', '2024-11-05'];
if (!supportedVersions.includes(version as string)) {
res.status(400).json({
jsonrpc: '2.0',
error: {
code: -32600,
message: 'Unsupported protocol version',
data: { supported: supportedVersions, requested: version },
},
id: null,
});
return;
}
next();
}
// https://modelcontextprotocol.io/specification/2025-11-25/basic/utilities/ping
export function handlePingRequest(req: Request, res: Response, next: NextFunction): void {
const pingRequest = PingRequestSchema.safeParse(req.body);
if (pingRequest.success) {
res.status(200).json({
jsonrpc: '2.0',
id: req.body.id,
result: {},
});
return;
}
next();
}
