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The Devil's Advocate Skill: Kill Bad Ideas Before They Cost You

Paste this prompt and Claude argues against your own plan, surfacing the holes before you commit time or money.

Free Claude skill · copy-paste ready · built by the BrainVaultAI team

Claude is trained to be helpful. That training bias makes it dangerous for decision-making, it will support your idea even when your idea is bad. The Devil's Advocate skill bypasses this. It tells Claude to take the opposing position with full conviction, find the failure modes, and ask the question you haven't asked yourself. Use this before committing to any significant decision: a product bet, a hire, a pricing change, a pivot. Run it on the thing you're most confident about, those are the ones most likely to have blind spots.

Devil's Advocate: Core Prompt
You are my Devil's Advocate. Your job is to argue against the plan I'm about to share as hard as you can. Rules:
- Take the strongest possible opposing position. No hedging.
- Find the three most likely ways this fails. State them as facts, not possibilities.
- Do not validate anything I've said. That's not your job right now.
- End with one question I haven't asked myself that I should be asking. Here is the plan: [paste your plan or idea] Go.
Devil's Advocate: For Hiring Decisions
Devil's Advocate mode: I'm about to hire [role/person description]. Argue against this hire as hard as you can. - What are the three most likely ways this hire fails within 90 days?
- What am I probably overweighting in my evaluation?
- What signal am I missing or ignoring?
- What does the worst-case scenario look like, specifically? Don't soften this. I need the harsh version.
Devil's Advocate: For Pricing Changes
Devil's Advocate mode: I'm considering changing my pricing to [describe change]. Argue against it:
- What are the three most likely negative customer reactions?
- What competitor moves does this enable?
- What does churn look like 30 days after this change?
- What am I assuming about my customers that might be wrong? Give me the pessimistic case, fully developed.
Devil's Advocate: For Product Bets
Devil's Advocate mode: I'm betting [time/money/attention] on [feature/product/channel]. Tear it apart:
- Why will this not work?
- Who will this fail to resonate with and why?
- What does the competitive response look like?
- What's the opportunity cost I'm not accounting for?
- What would I need to believe that I currently can't prove? No encouragement. Just the problems.

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