# Mentarium Thinking Skills

> Mentarium Thinking Skills: 12 skills that make Claude and ChatGPT think with mental models. Claude skills (SKILL.md) + ChatGPT instructions. One-time $29, in...

Canonical: https://mentarium.io/shop/thinking-skills.md

Claude skills (SKILL.md) + ChatGPT instructions

12 ready-made skills that make Claude and ChatGPT reason with mental models, step by step, and hand you a clean result.

$29

Coming soon

One-time payment. Instant download link by email. 7-day refund, no questions.

## What you get

- 12 Claude skills (SKILL.md) for Claude.ai, the Claude apps and Claude Code
- The same 12 as ChatGPT Custom GPT / Project instructions, plus a knowledge file with the Mentarium frameworks
- Install guide for both, in plain steps
- Personal and team use; edit them as you like

## The 12 skills

1. first-principles: break a problem down to basic truths and rebuild
2. inversion: list how to fail, then turn it into a plan
3. pre-mortem: imagine the project failed and rank the risks
4. second-order: map consequences three levels out
5. bias-audit: check a plan or text against the Bias Radar
6. decision-loop: run a full decision and get a journal-ready summary
7. steelman: build the best version of the other side
8. opportunity-cost: compare paths by what each gives up
9. priority-matrix: Eisenhower + Pareto on your task list
10. five-whys: root cause analysis
11. red-team: attack an idea or a strategy
12. weekly-review: a weekly review run with models

## Save with a bundle

Thinking Skills + Field Guide

$49 · save $-6

 Coming soon

Mentarium Complete

$69 · save $3

 Coming soon

## Questions

### Do I need a paid Claude or ChatGPT plan?

Skills work wherever your Claude plan supports skills; the ChatGPT versions need a plan that lets you create Custom GPTs or Projects. The files are plain Markdown, so you can also paste them into any assistant.

### How is this different from the free Decision Coach?

The Decision Coach is a connector for guided decisions. The skills are 12 separate thinking moves you call by name, they work offline from any account, and you can edit them.

### How do I get the files?

Right after paying you land on your downloads page, and we email you the same private link. Lost it? [Resend it here](https://mentarium.io/downloads).

### Can I get a refund?

Yes, within 7 days of buying, for any reason. Reply to your order email or write to support@mentarium.io.