Diagnosis before answers
Every submission is analyzed for the misconception behind it — an off-by-one, a wrong variable, a misread data structure — and labeled with the concept involved so mistakes become vocabulary you can reason about.
How CodeLens Works
CodeLens is built on a simple belief: you learn more from understanding one mistake than from copying ten solutions.
Core principles
Progressive hints
Your first hint is a gentle question. Ask again and hints get more concrete. The full conceptual explanation stays behind a deliberate click, because struggling productively is where learning happens.
Honest analysis
CodeLens reviews your code statically. It never claims to have executed your program or states what your code 'prints'. When its analysis is uncertain, it says so.
A typical session
- 1. Choose a problem at your level — beginner, intermediate, or advanced.
- 2. Write Python in the editor and press Analyze My Code.
- 3. Read your diagnosis and first hint. Think. Change something yourself.
- 4. Submit again. Hints escalate only as your attempts show you need them.
- 5. Watch your concept progress and difficulty level adapt on the Progress page.
Current limitations
- Python only (more languages may come later).
- Your code is not executed; correctness is judged by static reasoning against the problem intent.
- Progress is stored in this browser only — clearing site data resets it.