mcp-authentication-heade-custom-headers-defined-in-streamablehttpclienttran-e63e157d

THEN Pass the requestInit object (including custom headers) as part of the second options argument, not as a third separate argument. The constructor expects two arguments: URL and options (where requestInit is a property). Using three arguments causes headers to be ignored.

const transport = new StreamableHTTPClientTransport(
  new URL(serverUrl),
  {
    sessionId: sessionId,
    requestInit: {
      headers: {
        "Authorization": "Bearer " + token,
      }
    }
  }
);