When ChatGPT forgets you're using GDScript and sends code with spaces instead of tabs again, you can use this tool to convert the default 4 spaces to a tab character (also normalizes line ending types to Windows.)
Originally created it as a Python script with unit tests, then figured it'd be less effort to use it if it were just a webpage, so I can both bookmark it and leave it open in a tab. You can find the Python version in this repo too, in case you're curious.