MastoBrainz bridges the gap between your music and Mastodon. It harnesses the data from ListenBrainz, a platform that logs and shares your music listening habits, to seamlessly update your Mastodon profile with your currently playing track or the last piece of music you enjoyed.
Just did this a few hours ago. I don't see anything in my timeline and I listened to a full album since then. It works. I misunderstood what the tool does. I was looking in my timeline to see if there's something posted.
I keep getting an error saying "You can't have two different pieces of information in one place.", which I assume is something to do with the fact that you can also have it link to twitch, but I have the twitch functionality disabled