Every server plugin must have a general descriptor that provides information to the plugin API, and a type-specific descriptor that provides information about the plugin interface for a given type of plugin. The structure of the general descriptor is the same for all plugin types. The structure of the type-specific descriptor varies among plugin types and is determined by the requirements of what the given type needs to do. The server plugin interface also enables plugins to expose status and system variables. These variables become invisible through the SHOW STATUS and SHOW VARIABLES statements and through the corresponding INFORMATION_SCHEMA tables.

On the client side, the architecture is a bit different. Each plugin must have a descriptor, but there is no division into separate general and type-specific descriptors. Instead, the descriptor for all client plugin types begins with a common set of members, which are followed by any additional members required to implement speicific plugin types.