The Castagne Editor provides a few Editor Tools to help the creation of the characters. These are located at the bottom of the editor window.
Tools may be changed through the Tool button, and may be expanded with the ^^ button
This tool shows the various compilation errors. You may go to the associated file when possible by double clicking an element.
This tool can show the current state of input, and even overwrite it for various players.
The input viewer will display input for the current main entity of a player.
Input overwriting only works for direct and combination game inputs.
This part is very probably going to be rewritten somewhat for v0.59, so in the meantime you should look at the implementation of the other ones yourself. Some pointers: