This tool takes your textbox mashing as an input and gives you detailed statistics on how you did to help you improve. The tool continues to receive input even after losing focus, so you can mash in the Undertale game window and it will still be picked up by the tool.

NOTE: Your antivirus might pick up on this file because of the way it works. I can provide the source code on request, and I'll try to get a github page at some point.