mcp-sse-timeout-sse-connection-from-mcp-server-to-client-cursor-ti-015db008

THEN Implement a keep-alive mechanism by periodically writing a comment line ': keepalive\n\n' to the SSE response stream. Set an interval (e.g., 25 seconds) to write this comment before the client's timeout threshold (typically 5 minutes). This prevents the connection from being considered idle and terminated.

// Inside the SSE endpoint handler
const KEEP_ALIVE_INTERVAL_MS = 25000;
const intervalId = setInterval(() => {
  res.write(': keepalive\n\n');
}, KEEP_ALIVE_INTERVAL_MS);
// Store intervalId to clear on connection close.