Which communications management practice specifies all systems and platforms used to share information?

The practice that specifies all systems and platforms used to share information is referred to as agreements. Agreements are essential because they outline the commitments between different organizations or entities regarding communication systems and protocols. These agreements help ensure that all parties understand what systems will be used for data exchange and how information will flow between them. This clarity is crucial for effective communication and coordination during emergencies or incidents, as it establishes a common framework that guides how communication will occur.

In the context of the other choices, coordination focuses more on how different organizations work together rather than specifying the tools used. Protocols are more about the established procedures for communication rather than the systems themselves. Directives typically provide orders or guidance for action but do not directly address the specifics of communication systems or platforms. Thus, agreements play a vital role in ensuring a cohesive communication strategy supports incident management operations.