Error Tracker MCP Server

#!/usr/bin/env node /** * Backwards-compatible MCP Server * * This server supports both transport protocols: * 1. Streamable HTTP (protocol version 2025-03-26) - Modern transport * 2. HTTP + SSE (protocol version 2024-11-05) - Legacy transport for compatibility * * Endpoints: * - /mcp (GET/POST/DELETE) - Streamable HTTP transport * - /sse (GET) - Legacy SSE transport stream establishment * - /messages (POST) - Legacy SSE transport message endpoint */ import { Request, Response } from "express"; import { randomUUID } from "node:crypto"; import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js"; import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js"; import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js"; import { createMcpExpressApp } from "@modelcontextprotocol/sdk/server/express.js"; import { isInitializeRequest, } from "@modelcontextprotocol/sdk/types.js"; import { registerTools } from "./server-tools.js"; import { loadConfig } from "./config.js"; // Type for transport storage (both types) type TransportType = StreamableHTTPServerTransport | SSEServerTransport; /** * Create and configure MCP server instance * Shared between both transport types */ const getServer = () => { const server = new McpServer({ name: "error-tracker-mcp", version: "1.0.0", }); // Register all tools registerTools(server); return server; }; /** * Start backwards-compatible HTTP server */ async function main() { const config = loadConfig(); const PORT = config.server.compatiblePort; const app = createMcpExpressApp(); // Store transports by session ID // Both transport types are stored in the same map const transports: Record<string, TransportType> = {}; //============================================================================= // STREAMABLE HTTP TRANSPORT (PROTOCOL VERSION 2025-03-26) //============================================================================= /** * Handle all Streamable HTTP requests on /mcp endpoint * Supports GET (SSE stream), POST (initialization and requests), DELETE (termination) */ app.all("/mcp", async (req: Request, res: Response) => { console.log(`Received ${req.method} request to /mcp (Streamable HTTP)`); try { // Extract session ID from headers const sessionId = req.headers["mcp-session-id"] as string | undefined; let transport: StreamableHTTPServerTransport; if (sessionId && transports[sessionId]) { // Existing session - validate transport type const existingTransport = transports[sessionId]; if (existingTransport instanceof StreamableHTTPServerTransport) { // Correct transport type - reuse it transport = existingTransport; } else { // Wrong transport type (SSE trying to use Streamable HTTP) res.status(400).json({ jsonrpc: "2.0", error: { code: -32000, message: "Bad Request: Session exists but uses a different transport protocol (SSE)" }, id: null }); return; } } else if (!sessionId && req.method === "POST" && isInitializeRequest(req.body)) { // New initialization request - create new Streamable HTTP transport transport = new StreamableHTTPServerTransport({ sessionIdGenerator: () => randomUUID(), onsessioninitialized: (sessionId) => { console.log(`Streamable HTTP session initialized: ${sessionId}`); transports[sessionId] = transport; }, onsessionclosed: (sessionId) => { console.log(`Streamable HTTP session closed: ${sessionId}`); delete transports[sessionId]; }, }); // Set up cleanup on transport close transport.onclose = () => { const sid = transport.sessionId; if (sid && transports[sid]) { console.log(`Transport closed for session ${sid}, cleaning up`); delete transports[sid]; } }; // Connect server to new transport const server = getServer(); await server.connect(transport); } else { // Invalid request - no valid session or not an initialization res.status(400).json({ jsonrpc: "2.0", error: { code: -32000, message: "Bad Request: No valid session ID provided" }, id: null }); return; } // Handle the request with the transport await transport.handleRequest(req, res, req.body); } catch (error) { console.error("Error handling Streamable HTTP request:", error); if (!res.headersSent) { res.status(500).json({ jsonrpc: "2.0", error: { code: -32603, message: "Internal server error" }, id: null }); } } }); //============================================================================= // DEPRECATED HTTP+SSE TRANSPORT (PROTOCOL VERSION 2024-11-05) //============================================================================= /** * GET /sse - Establish SSE stream for legacy clients * This is the deprecated SSE transport */ app.get("/sse", async (req: Request, res: Response) => { console.log("Received GET request to /sse (Legacy SSE transport)"); try { // Create new SSE transport // The transport will generate its own session ID const transport = new SSEServerTransport("/messages", res); const sessionId = transport.sessionId; // Store the transport transports[sessionId] = transport; console.log(`SSE session created: ${sessionId}`); // Clean up on connection close res.on("close", () => { console.log(`SSE connection closed for session: ${sessionId}`); delete transports[sessionId]; }); // Connect server to transport const server = getServer(); await server.connect(transport); } catch (error) { console.error("Error establishing SSE connection:", error); if (!res.headersSent) { res.status(500).send("Error establishing SSE connection"); } } }); /** * POST /messages - Handle messages for legacy SSE clients * Query parameter: sessionId */ app.post("/messages", async (req: Request, res: Response) => { const sessionId = req.query.sessionId as string; console.log(`Received POST to /messages for session: ${sessionId}`); if (!sessionId) { res.status(400).json({ jsonrpc: "2.0", error: { code: -32000, message: "Bad Request: Missing sessionId query parameter" }, id: null }); return; } const existingTransport = transports[sessionId]; if (!existingTransport) { res.status(404).json({ jsonrpc: "2.0", error: { code: -32000, message: "Not Found: No transport found for sessionId" }, id: null }); return; } if (existingTransport instanceof SSEServerTransport) { // Correct transport type - handle the message try { await existingTransport.handlePostMessage(req, res, req.body); } catch (error) { console.error("Error handling SSE POST message:", error); if (!res.headersSent) { res.status(500).send("Error processing message"); } } } else { // Wrong transport type (Streamable HTTP trying to use SSE) res.status(400).json({ jsonrpc: "2.0", error: { code: -32000, message: "Bad Request: Session exists but uses a different transport protocol (Streamable HTTP)" }, id: null }); } }); //============================================================================= // SERVER LIFECYCLE //============================================================================= // Start the server app.listen(PORT, () => { console.log(`Backwards-compatible MCP server listening on port ${PORT}`); console.log(` ============================================== SUPPORTED TRANSPORT OPTIONS: 1. Streamable HTTP (Protocol version: 2025-03-26) ✨ RECOMMENDED Endpoint: /mcp Methods: GET, POST, DELETE Usage: - Initialize with POST to /mcp - Establish SSE stream with GET to /mcp - Send requests with POST to /mcp - Terminate session with DELETE to /mcp 2. HTTP + SSE (Protocol version: 2024-11-05) ⚠️ DEPRECATED Endpoints: /sse (GET) and /messages (POST) Usage: - Establish SSE stream with GET to /sse - Send requests with POST to /messages?sessionId=<id> Server URL: http://localhost:${PORT} ============================================== `); }); // Handle graceful shutdown process.on("SIGINT", async () => { console.log("\nShutting down server..."); // Close all active transports for (const sessionId in transports) { try { console.log(`Closing transport for session ${sessionId}`); await transports[sessionId].close(); delete transports[sessionId]; } catch (error) { console.error(`Error closing transport for session ${sessionId}:`, error); } } console.log("Server shutdown complete"); process.exit(0); }); } main().catch((error) => { console.error("Fatal error:", error); process.exit(1); });