on_generate_tags function inside geanyctags.c file have hard-coded commands for usage of ctags for all platforms, which limits it's flexibility. https://github.com/geany/geany-plugins/blob/bc4dc07e4deb694b647977791a23af67... I'd love to fix it, but unfortunately my C, GTK and geany development skills are less than desirable to do so in any manner. :/