Function handleMcpPost

packages/mcp/src/handler.ts:24–118

(
  sessionManager: SessionManager,
  req: IncomingMessage,
  res: ServerResponse,
  body: unknown,
  query: Record<string, unknown>,
)

 * - Session ID not in Redis: 404 → client reinitializes.
 */
export async function handleMcpPost(
  sessionManager: SessionManager,
  req: IncomingMessage,
  res: ServerResponse,
  body: unknown,
  query: Record<string, unknown>,
): Promise<void> {
  const sessionId = req.headers['mcp-session-id'] as string | undefined;
  const message = body as JSONRPCMessage;

  logger.info(
    {
      sessionId: sessionId ?? 'new',
      method: 'method' in message ? message.method : 'unknown',
      hasAuth: !!(query['token'] || req.headers.authorization),
    },
    'MCP POST request',
  );

  if (sessionId) {
    const context = await sessionManager.getContext(sessionId);
    if (!context) {
      logger.warn({ sessionId }, 'MCP session not found in Redis');
      res.writeHead(404, { 'Content-Type': 'application/json' });
      res.end(JSON.stringify({ error: 'Session not found — please reconnect' }));
      return;
    }

    await sessionManager.touchContext(sessionId);

    // Notifications have no `id` and expect no response
    if (!('id' in message)) {
      res.writeHead(202);
      res.end();
      return;
    }

    try {
      const response = await processRequest(context, message);
      res.writeHead(200, {
        'Content-Type': 'application/json',
        'Mcp-Session-Id': sessionId,
      });
      res.end(JSON.stringify(response));
    } catch (err) {
      logger.error({ err, sessionId }, 'MCP request processing error');
      res.writeHead(500, { 'Content-Type': 'application/json' });
      res.end(JSON.stringify({ error: 'Internal server error' }));
    }
    return;
  }

  // New connection — authenticate and expect `initialize`
  const token = extractToken(query, req.headers.authorization);

  try {
    const context = await authenticateToken(token);