Build the ugly version first
My first version of any tool is ugly on purpose. Plain text, no styling, no extra features. I want to know the core idea works before I spend a minute making it look nice.
A pretty tool that doesn't solve the real problem is worse than an ugly one that does, because the polish tricks you into trusting it too soon. Starting ugly also makes each coding session shorter and easier to check, since there's less surface area for something to quietly go wrong. Once the plain version proves itself against real use, then it's worth asking for a cleaner look.
Try this today: strip your next tool idea down to the smallest plain version that could possibly work, build only that, and prove it handles a real case before asking for anything extra.