I'd say you should still work toward whatever your own interest with the tool is. If it seems like too much work, make a list of all the functionality you want,

I'd say you should still work toward whatever your own interest with the tool is. If it seems like too much work, make a list of all the functionality you want, figure out the easiest way to implement each, and work on the least-effort/highest-reward things first. And do whatever feels fun!