The skill
One instruction file, SKILL.md, in a folder called thinking-partner. Upload the .zip to Claude or ChatGPT, or add SKILL.md to a ChatGPT Project.
Install it
Claude claude.ai and the desktop app, any plan
- Download the .zip. Don’t unzip it.
- In Settings, under Capabilities, turn on Code execution and file creation (in some versions it’s called Create and edit files). Skills need it.
- Go to Customize, then Skills. Click +, then Create skill, then Upload a skill, and pick the .zip.
- Check it’s switched on in your skills list. Then start a chat and say “Poke holes in this”.
On a Team or Enterprise plan, an owner may need to allow skills first.
Claude Code
- Unzip it into your skills folder, so the file ends up at
~/.claude/skills/thinking-partner/SKILL.md. From your Downloads folder:unzip thinking-partner.zip -d ~/.claude/skills - Start Claude Code and type
/thinking-partner, or just say “Poke holes in this”.
ChatGPT Business, Enterprise, Healthcare and Edu
- Download the .zip.
- In the sidebar, open Plugins, then the Skills tab. Click Create, then Upload from your computer, and pick the .zip.
No upload option? Your workspace admin has to allow skill uploads.
ChatGPT personal plans: Free, Plus, Pro
These plans can’t install skills yet. A Project does the same job.
- Download SKILL.md.
- In the sidebar, start a new Project for it.
- Add SKILL.md to the project’s files.
- In the project’s instructions, write: “Follow the instructions in SKILL.md for every message.”
- Start your chats inside that project.
Say any of these to switch it on: “Poke holes in this” “Challenge this” “Play devil's advocate” “Stress test this” “Pre-mortem this” “Is this a good idea?”
How to use it
- Start a new chat and describe the plan in a few lines: a new hire, a price change, a second van, a new service.
- Say "poke holes in this". It restates your idea in one line, lists what has to be true for it to work, and goes after the weakest part first.
- Push back where it's wrong. It won't fold just because you're firm, but it changes its mind when you give it a reason.
- Close to deciding? Ask for a pre-mortem. It pictures the plan failing six months from now and lists the likely reasons, with the early warning sign for each.
It argues so you think harder. It only knows what you tell it, and the call is yours.