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name: devils-twin description: "The strongest possible case AGAINST what you just wrote — argued to win, not to check a box. Use when a document is about to ship and everyone around it already agrees: the twin writes the opposition's best memo (not a critique of yours), so you meet the real counter-argument before your audience does. Produces the opposing memo, the map of which of your claims it defeats/dents/leaves standing, and the pre-emption paragraph worth adding."

Devil's Twin

Critique finds weaknesses in your argument. The twin does something scarier: it writes the other side's argument, from their premises, at full strength — the memo your smartest opponent would circulate an hour after yours. If your document survives its twin, it will survive the meeting.

Required Inputs

• The document — full text. The twin argues against the strongest version of what you wrote, so it must see all of it.
• Who would oppose this in real life (optional but sharpening) — the CFO, the incumbent team, the sceptical customer, the regulator. The twin adopts their premises, not a generic contrarian's.

How the Twin Argues

• It starts from the opponent's values (their scoreboard, their risks), not from negations of yours — real opposition is a different worldview, not your worldview with "not" inserted.
• It concedes your strongest point early — sophisticated opponents do; conceding makes the rest of their case credible.
• It uses your own evidence where possible — the most damaging counter-memos re-read your data and reach the other conclusion.
• It is written to persuade your shared audience, in the register of your organisation — a memo, not a rant.

Output Format

1. The opposing memo (400-600 words) — standalone, signed by the persona ("Memo from the office of the CFO"), good enough that a reader wouldn't know which document you commissioned.
2. The battle map — your document's key claims, each marked: 💀 defeated (the twin's counter is simply better) / 🩸 dented (survives with repairs) / 🛡 held (the twin couldn't touch it) — with one line of why.
3. The pre-emption — the single paragraph to ADD to your document that answers the twin's best point before anyone makes it, drafted in your document's voice.
4. The honest verdict — one line: ship as is, repair first, or the twin's case is actually right (say so; it happens, and it's the cheapest place to find out).

Quality Checks

• The memo argues FROM the opponent's premises — deleting "not" from your claims would not reconstruct it
• It concedes at least one of your points — full-spectrum opposition is a strawman wearing a suit
• At least one of your claims is marked 💀 or the twin explains why your case is unusually airtight (rare; suspicious)
• The pre-emption paragraph is drop-in ready — your voice, your document's structure, no "as some may argue" throat-clearing
• If the twin's case is stronger overall, the verdict says so plainly

Anti-Patterns

• Do not write a critique with quotations — the deliverable is the opposition's own memo, structure and all
• Do not make the twin stupid to make you feel good — a weak twin is worse than none; it inoculates you against the wrong argument
• Do not have the twin invent facts — it may reinterpret your evidence and add commonly-known context, never fabricate data
• Do not skip the verdict to stay diplomatic — "repair first" beats a polite shrug
• Do not use the twin on documents whose audience is hostile already — it's for consensus rooms, where nobody else will say this

Example Trigger Phrases

• "Argue against this as hard as you can."
• "Write the opposition's best memo."
• "Everyone agrees with this doc: what's the strongest case against it?"
• "Make the case that we should not do this."