The user has great flexibility in controlling the tool since a Tcl interpreter is built in. This means that new code can be incorporated at runtime, program state can be queried and modified, and even replacement of program procedures is possible.

The objects are modeled using incr Tcl. Thus the objects themselves are Tcl commands that can be executed to get or configure object data or to run the object's methods. A user can write code and create new objects if so desired.

A Command input line is provided at the bottom of the user interface so that Tcl commands can be run while using the GUI. A window is provided to assist in the loading and management of code packages.

A number of sample packages, with all source code, is provided in the download package to assist the user in writing add-ons.