Hi everyone, I recently deployed my own MCP server in production using SSE as the transport type.
The problem is that every time I try to connect to the cursor from this server, I receive a “session id not found” message from my implementation.
Has anyone experienced a similar bug?
Here is my basic server implementation
import express, { Request, Response } from "express";
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js";
import { registerAllTools } from "./tools";
import cors from "cors";
export const server = new McpServer({
name: "mcp-clickup-helper",
version: "1.0.0"
});
registerAllTools()
const app = express();
app.use(cors());
const transports: {[sessionId: string]: SSEServerTransport} = {};
app.get("/health", (_: Request, res: Response) => {
res.send({
status: "ok",
});
});
app.get("/sse", async (_: Request, res: Response) => {
const transport = new SSEServerTransport('/messages', res);
transports[transport.sessionId] = transport;
res.on("close", () => {
delete transports[transport.sessionId];
});
await server.connect(transport);
});
app.get("/sse/health", async (req: Request, res: Response) => {
res.send({
status: "ok",
});
});
app.post("/messages", async (req: Request, res: Response) => {
const sessionId = req.query.sessionId as string;
const transport = transports[sessionId];
if (transport) {
console.log("sessionId", sessionId);
await transport.handlePostMessage(req, res);
} else {
res.status(400).send('No transport found for sessionId');
}
});
app.listen(3001, () => {
console.error("MCP Server running with sse transport");
});
Attached are images of the error log (MCP Cursor Output)
