Proxies, as any other {{UBIK}} object, require a MetaClass describing them. Since proxies have special features, they also have a special MetaClass, called a [[MetaProxy]]. A MetaProxy doesn't just have MetaProperties like a usual MetaClass, but it also has [[ProxyMetaProperty|ProxyMetaProperties]]. These ProxyMetaProperties define interface properties with several interesting details:
* The external system's name of the property
* The Ubikle's (content object's) property MetaProperty this ProxyMetaProperty corresponds to
* Whether to enable import for this property
* Whether to enable export for this property