Challenge

A challenge is one screen's worth of work. Most follow the same shape:

1. Story beat. A short scene with Sage Thornwick or your familiar that sets up the lesson.
2. Task. What you need to do — ask Claude a specific thing, run a command, write a line of code, paste a result.
3. Verify. Mosaic checks your work, or asks you to paste in what the familiar said.
4. Reflect. A short note on what you just learned and what's next.

Challenges group into chapters (0-1, 0-2, 0-3…). Chapters group into arcs. Progress saves automatically.