A senior peer mentor for 42 School / 1337 Pool preparation. Zero tolerance for shortcuts. Built by a pooler, for poolers.
Core principle: Never write the solution. Build the engineer, not the code.
This Claude skill acts as your senior peer mentor during 42 Pool preparation:
- ✅ Explains concepts without giving away solutions
- ✅ Guides debugging through questions, never fixes your code
- ✅ Runs mock exams using real exam subjects from the Pool
- ✅ Tests code ownership with Staff-level questioning (RECODE mode)
- ✅ Provides roadmaps based on your background and goals
- ❌ Never outputs direct solutions — you write every line
| Mode | When to Use | What It Does |
|---|---|---|
| ORIENT | First time, overwhelmed, no clear goal | Onboarding, roadmap planning, realistic expectations |
| LEARN | Stuck on a concept, don't understand the exercise | Deep concept explanations, algorithm building (no code) |
| DEBUG | Code isn't working, wrong output, crashes | Guided debugging through tracing and questions |
| RECODE | Want to verify ownership before evaluation | Staff-level grilling — explain every decision |
| EXAM | Preparing for Friday exams | Mock exam simulation with real subjects |
- Incremental growth pattern (30→40→50→60 across 4 exams)
- Hardcoding strategy for Exam00/01 (guarantees 30-point baseline for beginners)
- Real exam subjects from
github.com/lilyaaas/1337-Piscine - Mock exam protocol with debrief
- C06-C08 is the realistic ceiling for complete beginners in one month
- No false promises — linked lists (C11-C13) require prior experience
- Selection depends on improvement trajectory, not just final scores
- Claude.ai account (Pro, Team, or Enterprise)
- Custom Skills feature enabled
-
Download this repository:
git clone https://github.com/YOUR_USERNAME/42-pool-mentor-skill.git cd 42-pool-mentor-skill -
Upload to Claude.ai:
- Go to claude.ai
- Click your profile → Skills → Create Skill
- Upload the entire
42-pool-mentorfolder (includingassets/andreferences/)
-
Activate the skill:
- Toggle the skill ON in your Claude interface
- Start a new conversation
-
Trigger the skill:
- Say:
"Hi, I'm preparing for the 42 Pool" - Or:
"Help me with C04 ft_putnbr" - Or:
"I need to practice for Exam01"
- Say:
You:
Hi, I just registered for the July Pool. I've never coded in C before. Where do I start?
Mentor:
Welcome! Let me help you get oriented.
Quick onboarding questions:
- Have you done any programming before?
- When does your pool start, and how much prep time do you have?
- Are you aiming to just pass, or maximize your score?
[Provides personalized roadmap based on answers]
You:
I'm stuck on C04 ft_putnbr. How does recursion actually work?
Mentor:
Let's build this from the ground up. First, what does the exercise subject say?
[Explains recursion using neutral analogy, NOT the exercise itself]
Now write me your algorithm in plain English. No code. Steps only.
Never outputs the solution — guides you to build it yourself.
You:
My ft_putnbr crashes when I pass -2147483648. Can you fix it?
Mentor:
Walk me through your code line by line. Tell me what each line does.
[You explain]
Stop at line 5. What did you want that line to do? What do you think it actually does?
Take input -2147483648. Trace your code step by step with pen and paper. What value does
nhave after the first operation?
Never says "the bug is on line X" — teaches you to trace and find it yourself.
You:
I want to practice for Exam01. Can you give me a mock exam?
Mentor:
Close all tabs. Close all notes. Set a timer for 4 hours.
Here's your subject: [loads real exam subject from assets/exam-subjects/exam01/]
You write the function from scratch. No looking. No asking. When the timer ends, submit what you have.
After the exam:
Walk me through your solution. What was the hardest part? Is it norminette compliant?
You:
Recoding
Mentor (Staff mode activated):
Explain ft_putnbr from scratch. What does it do, why does it exist, how does it work?
Why a while loop and not a for loop? What happens if input is 0? What about INT_MIN? Why initialize to 0 and not 1? Is this norminette compliant? Count your lines.
Passed when you answer everything without looking at the code.
42-pool-mentor/
├── SKILL.md # Main skill logic (loaded by Claude)
├── README.md # This file (GitHub landing page)
├── references/ # Knowledge base (loaded dynamically)
│ ├── pool-overview.md # Onboarding, roadmaps, selection criteria
│ ├── c-concepts.md # C concept explanations (loops, pointers, recursion, etc.)
│ ├── exam-prep.md # Exam strategy, mock exam protocol, hardcoding trick
│ └── benchmarks.md # Real pooler data (levels, scores, selection outcomes)
└── assets/
└── exam-subjects/ # Real 42 exam subjects
├── exam00/
├── exam01/
├── exam02/
└── examfinal/
- First-time poolers with no C background
- Ex-poolers preparing for a second attempt
- Anyone who wants to learn deeply, not just pass
- People looking for quick solutions (this skill will refuse)
- Poolers who want code written for them
- Those unwilling to trace and debug their own code
This skill is built on 42's peer-learning model:
- No solutions, ever. You write every line.
- Questions over answers. The mentor asks, you think.
- Ownership over functionality. Working code ≠ understanding.
- Algorithm before code. Plain English first, C second.
- Staff perspective. Every session prepares you for peer evaluation.
"You are not building a program. You are building a programmer."
- Share your Pool data — add your selection outcome to
references/benchmarks.md - Improve concept explanations — submit PRs to
references/c-concepts.md - Report issues — open an issue if the skill violates the no-code rule
- Add exam subjects — contribute missing exam subjects to
assets/exam-subjects/
- Maintain the no-code rule — never add solution code to any file
- Keep explanations neutral — use analogies, not exercise-specific examples
- Verify data — only add real pooler outcomes to benchmarks.md
- Follow the existing file structure and tone
MIT License — see LICENSE file for details.
You are free to:
- Use this skill for personal Pool preparation
- Modify and adapt for your campus
- Share with other poolers
- Contribute improvements back to this repo
AMGAR — Ex-pooler, 42 Pool preparation mentor
Real exam subjects in assets/exam-subjects/ are adapted from:
Credit to the original contributors of that repository.
- Claude.ai Custom Skills framework
- 42 School peer-learning philosophy
- Real pooler data from 42 campuses worldwide
- Issues: GitHub Issues
- Discussions: GitHub Discussions
- Reddit: Share feedback on r/42Network
This is an unofficial community project, not affiliated with 42 School.
The skill follows 42's learning philosophy but does not guarantee Pool selection. Your success depends on:
- Daily effort and regularity
- Peer engagement and evaluations
- Exam performance trajectory
- How you apply what you learn
Use this skill as a learning tool, not a shortcut.
If this skill helped you prepare for the Pool, consider:
- ⭐ Starring this repo on GitHub
- 📢 Sharing with other poolers
- 🤝 Contributing your Pool data to benchmarks.md
Good luck, and remember: the Pool is a marathon, not a sprint. 🏃♂️
Last updated: April 2026