The Schematic Application Programming Interface (API) reference details the object interfaces for schematic objects such as schematic documents and schematic design objects. The Schematic API is defined in the RT_Schematic unit which is embedded in the scripting engine or added explicity in the Uses clause on a unit in a server project.
Schematic API, Schematic Object Model and Functions
The Schematic API consists of the Schematic Object model and Schematic API functions. The Schematic API is supported by the Schematic Editor in Altium Designer. The Schematic design object interfaces and methods are available to use in your scripts in all script languages that Altium Designer supports.