I had discolsed my DIY tool for GR-KURUMI as OSS with BSD lite license. You may use them AS-IS with MacOSX. If you use Linux, you may need to modify sthe source codes a little.
(1) Terminal tool for printf debug with GR-KURUMI, KR-COTTON, etc.
https://github.com/digiponta/TERM4GR-KURUMI
(2) Program Writing tool to GR-KURUMI, GHR-COTTON, etc.
https://github.com/digiponta/VSW2GR-KURUMI
Of course, Yon can modify their source codes without notifying to me.