From prompt to Excel custom function in 30 seconds
xllify is a packaging tool and runtime that allows functions written in Luau and Python to be used as high-performance custom functions in your Microsoft Excel workbooks. In a bizarre collision of 1990s style development (the Excel C SDK) and 2025 era AI, I’ve been experimenting with having a Claude agent write Excel custom functions for xllify! As Excel itself is now fat and 40 years old, it could be donning ill-fitting running gear and developing an irrational interest in coffee beans....