Library skill · Thinkers' principles
Munger-style inversion review
Reviews a plan by inversion: lists how it would surely fail, separates what the business couldn't survive, and checks it through several models, from ideas Charlie Munger described. Use it when before committing to a plan, a launch, a large contract or a purchase.
Not affiliated with or endorsed by Charlie Munger or their companies. About these principles: Charlie Munger's ideas, explained.
AI skill
Have your AI find how your plan would fail before it does
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Works in Claude, ChatGPT, and coding agents. On Team and Business, this library skill in your pod updates itself when we improve it.
When to use it
- Before committing to a plan, a launch, a large contract or a purchase
- A goal everyone agreed on too quickly and nobody has stress-tested
What you give it
- The plan, goal and success measure
- Key facts: money, people, dependencies
- What the team already worries about
- Consequences the business could not survive
What you get
A table of specific failure modes with mechanisms, the places never to go with a rule for each, a multi-model read, and the plan changes with owners.
How it works
- State the goal and success
- Invert it (principle 1)
- Mark the ones you can't survive (principle 2)
- Check the plan against each failure
- Look through other models (principle 3)
- Check quality against price (principle 4), when buying something
- Rewrite the plan
Example
What you give it
We're a 12-person bakery-café chain with 3 shops. Plan: open 4 more shops in 12 months, funded by a 90M yen bank loan. One supplier provides all our flour at a discount. Our head baker trains everyone. Same-store sales grew 8% last year.
What you get back (the start of it)
These are principles Charlie Munger described publicly. Not affiliated with or endorsed by Charlie Munger or their companies. The list of models is ours.
How we'd make sure it fails
| # | Failure | Mechanism | Recoverable? | Plan today |
|---|---|---|---|---|
| 1 | Open all 4 before any is profitable | Loan repayments start while 4 shops lose money | No, if cash runs out [check: loan terms and cash] | Walks into it |
| 2 | Lose the flour supplier | One supplier; the discount hides the dependency | Yes, at higher cost | Walks into it |
| 3 | The head baker can't train 4 new teams | One trainer for 7 shops | Partly: quality drops | Walks into it |
Places we must never go
Running out of cash before new shops break even. Rule: open one shop at a time; the next opens only when the last one covers its own costs [check: months to break even from the first 3 shops].
The rest of this output, the full steps and the checks the AI runs before it answers are in your pod once you add the skill.
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Changelog
- v1.0.2 · · Description: a lowercase letter mid-sentence.
- v1.0.1 · · Example output now opens with the attribution and not-affiliated lines, as the skill's own checks require.
- v1.0.0 · · First release.
Sources
- Poor Charlie's Almanack - Stripe Press (read 2026-11-04)
- Berkshire Hathaway 1996 shareholder letter (Charlie's dictum, inverting) (read 2026-11-04)
- Berkshire Hathaway 2023 shareholder letter (Charlie's 1965 advice) (read 2026-11-04)