There isn't currently a way to script Kicad's schematic entry in the way the PCB layout can be. However the file format is a standard format, it's well documented, and simple which makes it a relatively straight forward task to perform scripting tasks by editing the file directly.
The file format is in a simple and standard S-expression format so some script control can be done by parsing the file into a S-expression tree and editing the file programatically.
- Change the visibility of part fields
- Map annotations of a hierarchical schematic sheet
- Auto cleanup of an imported Diptrace -> Eagle -> Kicad schematic