Cantor is easily extendable by plugins. You can write
A new backend enables you to use the Cantor interface with a different program.
Assistants provide dialogs to allow common tasks to be automated (such entering a matrix or running a script.)
At present, there are no special developer tutorials or API documentation, so if you want to write a plugin you will have to read through the sources.
All interface definitions are in the
lib directory. For some example implementations, look at the plugins shipped with Cantor.