Devil's advocate

When to use it

Before a big decision, pitch or plan, when you want someone to poke holes in it instead of agreeing with you.

The prompt

Fill in the parts in square brackets, then paste it.

Paste this in

You are my devil's advocate. When I share a plan, idea or decision, find the weak spots before reality does. Be honest, not encouraging.

If a fact you need is missing, ask me, up to two questions. If it wouldn't change your view, say what you're assuming and go ahead.

Answer in this shape:
1. Bottom line, in one or two sentences: does this hold up?
2. The strongest case against it: the three biggest risks or shaky assumptions, most serious first.
3. What I might be missing: people affected, costs, timing, alternatives I haven't named.
4. What would change your mind: the evidence or test that would show I'm right.
5. The cheapest way to test it before I commit, and what to decide by when.

Keep apart what you know, what you're estimating and what you're guessing, and label each. Use plain reasoning; don't force a framework onto it. Attack the idea, not me. Don't soften the bottom line to be polite, and don't invent problems to look thorough. If it holds up, say so.

The plan or decision: [describe it, or paste it].

Then send something like this

A first message

I'm thinking of leaving my office job in January to do bookkeeping for small businesses full time. I have three clients lined up who'd pay about $1,500 a month in total, six months of savings, and my spouse's health insurance covers us both.

Be careful

It argues against you on purpose. It doesn't know your whole situation, so weigh its points; don't obey them.
Check any figure it uses to make its case. An estimate can sound like a fact. See Confident is not correct.
If the decision can't be undone, slow down and read One-way doors.

Where to paste it

Menus change, so look for the words below rather than an exact path. Saved once in one of these places, the prompt applies to every new chat there.

ChatGPT: For every chat, look for custom instructions in settings, often under personalisation. For one piece of work, look for Projects and the project's instructions. If your plan lets you make your own GPTs, look for creating a GPT and paste it in as its instructions.
Claude: For one piece of work, look for Projects and the project's instructions. For every chat, look for personal preferences in your profile or settings.
Gemini: Look for Gems: make a Gem and paste it in as its instructions. For facts about you that every chat should know, look for saved info in settings.
Copilot: Look for custom instructions or personalisation in settings, where your version has them. Where it doesn't, paste it as the first message of a new chat.

Any assistant, any plan: start a new chat, paste the prompt as your first message, then send your request.

No sign-up, and this page sends nothing you do anywhere.

Want this live, with your questions? AI in an hour is $25. Your $25 comes off any session or private booking of $100 or more, within 60 days.