First time I played, I couldn't figure out how to close the spell book — I realized this time that there's a white arrow on the light yellow page. 
Maybe putting the spell UI on the bottom of the screen, toolbar style, instead of covering the middle, would make it easier (and juicier) to see what the spell you just chose did.

I didn't play long enough to have valuable opinions on the game loop — except that I felt like I soft-locked myself by buying the Spinner too early and not knowing how to turn it off, so I couldn't do the spell that takes threads anymore (Spinner kept eating my threads.) EDIT: Oh, I see you're planning to change that.

The spirit's animation feels a little mechanical but I do like the leaning and the overshoot!

I  like this concept and want to see how you develop it further! Cheers!

Love the art, it's pretty cute, and the music is very soothing and it's something I would expect from a chill idle game.

My only issue is that clicking on the spellbook and map also sends your spirit there, I would've liked that the UI elements are not "click-through". Maybe the game should even be paused while choosing what to pick, as I felt like I'm missing out on collecting while deciding, it kinda clashed with the chill feeling the game was providing (although, that could just be my issue since everything is infinite and I'm technically not losing anything - it just feels like I am).

Other than that, I liked it overall and even though I don't usually play (or prefer) idle games, I played this to the end :)