Most AI explains things to you, you nod along, and a week later it's gone. Jane Street, the trading firm famous for brutal interviews, open-sourced a tutor skill that does the opposite: it quizzes you to find your real level, teaches by asking one question at a time, and only marks a skill as learned after you prove it twice. It's past 1,000 GitHub stars in its first six days.
Here's what it does, how to use it in the free Claude chat or in Claude Code, and the catch.
What it does for you
- A placement quiz first: 3-5 questions from easy to hard, so it starts where you actually are. It teaches nothing until that's done.
- One question at a time. When you're wrong, it asks a narrower question that shows you the hole in your reasoning, and only explains after 2-3 tries.
- A skill map: the topic is split into 4-10 parts, each scored 0 (never heard of it) to 5 (could teach it), with progress bars after every change.
- Strict grading: a level goes up only after 2+ separate checks, at least one from memory. No flattery.
- Surprise review: it re-tests earlier parts without warning and drops your level if you've forgotten.
- A final mixed test across everything. The course ends only when every part is at 4 out of 5.
Free, for your email
Get the full setup steps + the copy-paste setup prompt
The rest of this guide (4 more sections, 1 copy-paste prompt) opens right here. The setup prompt, one paste into Claude that sets it all up, comes by email only. Use your real address.
Unlocks: Setup in the free Claude chat (no code) · Setup in Claude Code · The catch · Sources
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