You can save your custom tools so you can reuse them in other GeoGebra constructions. In the Tools Menu, select Manage Tools to open this dialog. Then, select the custom tool you want to save from the appearing list. Click on button Save As… in order to save your custom tool on your computer.
This dialog also allows you to remove or modify tools. If you decide to modify a tool, new GeoGebra window appears. The input objects are listed as free objects in it. If you have done finishing your changes, you can save the tool via option Create new tool in Tools Menu. Keep the old name to overwrite the tool. To overwrite a tool which was already used, the types of input and output objects must stay the same.