inversion

inversion is a skill for Claude Code, Codex from martineserios/thebrana. It costs 96 tokens per session (3,668 once invoked), scanned A, a copy of inversion, MIT.

A method for comparing named options against weighted criteria, where more important criteria count more toward the result. It also examines trade-offs and whether changing the weights would change the recommendation.

In plain words
What is it for?
Use it to choose between products, designs, vendors, or other alternatives when cost, speed, quality, constraints, or stakeholder preferences must be balanced.
Why use it?
It makes subjective choices more visible and easier to explain by showing how each option was scored.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument; installed under .agents/ (shared by several agents).

Good fit Use it to choose between products, designs, vendors, or other alternatives when cost, speed, quality, constraints, or stakeholder preferences must be balanced.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/martineserios/thebrana/inversion
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add martineserios/thebrana --skill inversion
Clone the repo
git clone --depth 1 https://github.com/martineserios/thebrana

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for inversion

README.md
[![agentmods](https://agentmods.dev/badge/skills/martineserios/thebrana/inversion/github.svg)](https://agentmods.dev/skills/martineserios/thebrana/inversion)
Your own site
<a href="https://agentmods.dev/skills/martineserios/thebrana/inversion"><img src="https://agentmods.dev/badge/skills/martineserios/thebrana/inversion/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for inversion

Your own site · 80×15
<a href="https://agentmods.dev/skills/martineserios/thebrana/inversion"><img src="https://agentmods.dev/badge/skills/martineserios/thebrana/inversion.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 96 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,668 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00096 $0.03668
Opus 5 $0.00048 $0.01834
Sonnet 5 $0.00019 $0.00734
Haiku 4.5 $0.00010 $0.00367

Measured 8d ago against content hash 8e459f3e8a0c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

inversion scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to inversion — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/inversion/SKILL.md · 530 lines

How it starts

The opening of the file, as written. The whole thing — 530 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Inversion

"Invert, always invert." Apply Carl Jacobi's mathematical principle and Charlie Munger's investing wisdom to solve problems by thinking backward from failure.

When to Use This Skill

  • Goal setting - Define what would guarantee failure, then avoid it
  • Risk analysis - Identify what could destroy your project before starting
  • Decision making - Evaluate choices by examining their worst outcomes
  • Problem solving - When direct approaches aren't working, reverse the question
  • Strategy development - Find competitive advantages by avoiding common mistakes
  • Personal development - Identify habits and behaviors that guarantee failure

Methodology Foundation

Aspect Details
Source Carl Gustav Jacob Jacobi (1804-1851), mathematician; Charlie Munger, investor
Expert Munger credits Jacobi: "Invert, always invert" (from "man muss immer umkehren")
Core Principle Many problems are best solved backward. Instead of asking "How do I succeed?", ask "What would guarantee failure?" then avoid those things.

What Claude Does vs What You Decide

Claude Does You Decide
Structures content frameworks Final messaging
Suggests persuasion techniques Brand voice
Creates draft variations Version selection
Identifies optimization opportunities Publication timing
Analyzes competitor approaches Strategic direction

What This Skill Does

  1. Reveals hidden risks - Surfaces dangers invisible when thinking forward
  2. Simplifies complex problems - Failure paths are often clearer than success paths
  3. Prevents catastrophic mistakes - Avoidance is easier than achievement
  4. Improves decision quality - Forces consideration of downside scenarios
  5. Unlocks creative solutions - Reverse framing reveals new approaches

How to Use

Invert a Goal

Apply Inversion to this goal:
[describe your goal]

What would GUARANTEE failure? What should I avoid at all costs?

Read the full file on GitHub · 530 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 530 lines · 96 tokens per session scan A 8e459f3e8a0c

Subscribe to this mod's changes

inversion is a skill published in the GitHub repository martineserios/thebrana (3 stars, last pushed today), licensed MIT. It adds 96 tokens to every session and 3,668 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to inversion, differing in 0 lines, and is treated as a copy.