The number of available requests have been kept small to minimize the extension complexity. The lack of events or errors is also to minimize extension complexity.

The extension can be used by any X client authorized to connect to an XYZ-capable server. There is the potential for multiple clients to interleave XYZ requests and make the use of XYZ confusing. Since the extension is intended only for the limited application of server instrumentation and tracing, this is not deemed a problem. The extension was designed under the assumption that a single XYZ client would be used to monitor the server via the XYZ facility.