This reminds me of something from my ancient past. Back in the early-ish days of Apple, there was a development system called MPW (Macintosh Programmer’s Workshop) which included its own little kludgy shell.
The weird thing about it though was while you could enter commands on the command line like in any shell, you could prefix them with the word commando (presumably a portmanteau of “command” and “window”) and this window would pop up showing various buttons, checkboxes, etc. correponding to command line options. When you ok’d the window, it would generate the command line for you.
I’m rather hazy about how all this worked, but I think there was some sort of template language to define the window layout if you wanted to add commando support for your own tool? And presumeably, as you say, you could restrict what’s possible with the window interface as you deemed fit?