This document adds a basic toolkit definition to the ISO 21219 series specifying the Message Management Container (MMC) which is used by all TPEG applications to provide information about the handling of messages on the TPEG client side. The MMC holds administrative information allowing a decoder to handle the message appropriately. This information is not aimed at the end user. The MMC is a toolkit and not a stand-alone application but is included by TPEG applications.