# The AI made my price-increase email "more compelling." It also invented a 40% cost jump. > An AI made a coffee roaster's price-increase email sound great, and slipped in a cost jump she never gave it. We tested a How I AI workflow that makes the AI argue with your draft first. By Jordan Menlo · Published October 25, 2026 Section: Markets & Main Street › Small Business · Series: AI Prompts, Reviewed (https://mcafax.com/notebook/prompts) Canonical: https://mcafax.com/notebook/ai-prompt-review-business-writing Source: MCAFax, The Broker's Notebook (https://mcafax.com/notebook). MCAFax is not a lender or a law firm. --- "Due to a 40% rise in green coffee costs, new pricing takes effect with your next order." That line went into **Marisol's** price-increase email after she asked an AI to make it more compelling. **Marisol owns Lantern Hill Roasters (a made-up coffee roaster)**, and she sells wholesale beans to 12 local cafes. It read great. She almost hit send. Her real green coffee cost went up about 17%, not 40%. And she had promised her cafes 30 days' notice. Ask the AI to argue with your email, not to polish it. **AI Prompts, Reviewed** takes one prompt or workflow from How I AI, Claire Vo's show where guests share their screens and walk through how they really use AI. We run it on a small-business job, score it, and tell you what we'd change. **Credit:** Based on "How to Use AI as a Sparring Partner to Improve Your Business Writing," a workflow from How I AI (hosted by Claire Vo, written up by the ChatPRD team), shown by Hilary Gridley, Head of Core Product at WHOOP, in the episode "How I AI: Hilary Gridley's Playbook for Scaling Yourself with Custom GPTs." [Read the original workflow on How I AI](https://www.chatprd.ai/how-i-ai/workflows/how-to-use-ai-as-a-sparring-partner-to-improve-your-business-writing). [Watch the full episode](https://www.chatprd.ai/how-i-ai/scaling-yourself-as-a-manager-with-custom-gpts). Guest site: none listed on the How I AI workflow page. ## What the original does In the episode, Hilary gives ChatGPT her own messy newsletter draft. She asks it to say her thesis back, then how to make it more compelling, then what blind spots she has. She writes the final version herself. The written workflow has 4 steps: - Write the first draft yourself, then have the AI restate the claim, evidence and the action you want, without rewriting. - Ask for ways to make the point stronger, without adding facts. - Have the AI act as a skeptic and find weak claims, missing evidence and counterarguments. - Pick a structure, revise in your own words, and check every fact, quote and promise. The line we'd tape to the monitor: **"Do not be agreeable and do not rewrite."** ## The test Everything here is made up. Lantern Hill Roasters sells to 12 cafes that order **410** pounds a week in total. - Old wholesale price: **$11.50** a pound - New price: **$12.75** a pound, a raise of **$1.25** - Why: green coffee up **$0.80** a pound (from **$4.80** to **$5.60**), bags up **$0.20**, delivery up **$0.25** - Start date: orders placed on or after December 1, about 30 days out Marisol's rough draft was honest but vague. It said "a modest increase" and "rising costs." **Run 1, the shortcut:** "Make this price increase email more compelling and professional." The new version was smooth and confident. It also added a **40%** cost rise she never gave it, swapped her December 1 date for "your next order," and cut the line thanking cafes for sticking with her. A made-up number and a broken promise aren't polish. They're what a cafe owner forwards to a competitor. ## The rerun **Run 2:** same tool, our prompt below. It locks the facts, restates before it edits, and argues like the customer. The restate step caught the first problem. Asked to say the email back, the AI couldn't name the new price or the start date, because her draft never stated them. The skeptic step caught the second. It played her biggest account, a cafe buying **60** pounds a week, and asked what the raise costs them. The math: **60 x $1.25 = $75** a week, or **$3,900** a year. That's a number a cafe owner will notice, so the email needs a real reason. Her real reason added up exactly: **$0.80 + $0.20 + $0.25 = $1.25**. Green coffee alone went from **$4.80** to **$5.60**, and **$0.80 / $4.80** is about **17%**. Then the stakes. Across all **410** pounds, the raise brings in **410 x $1.25 = $512.50** a week. Losing that one big cafe would cost **60 x $12.75 = $765** a week in sales. That's more than the whole increase. Marisol rewrote the email herself. It states the old and new price, the December 1 date, the three cost lines, and an offer to call the big accounts first. She phoned the **60**-pound cafe before sending anything. ## Verdict: 8/10 **Strengths:** the restate step shows you what your email actually says, not what you meant. The skeptic step is the one most owners skip. And it keeps the final words yours. **Weakness:** it's built for a newsletter writer working on an argument. Owners write emails with prices, dates and promises, and the original doesn't tell the AI which facts it may never touch. **Founder tweak:** list your locked facts at the top, make the AI play your biggest customer, and compare every number and date after each pass. ## Copy the MCAFax version This is our own rewrite, not the original. **[Copy the original from Hilary Gridley on How I AI](https://www.chatprd.ai/how-i-ai/workflows/how-to-use-ai-as-a-sparring-partner-to-improve-your-business-writing).** ``` I own [business type]. Below is my draft of [email or letter] to [who gets it]. I want the reader to [action you want, for example, accept a new price and keep ordering]. LOCKED FACTS. Never change, add to, or round these: Price or amount: [$]. Date: [date]. Promises I made: [list]. My real reasons and numbers: [list each with its source]. Step 1. Do not rewrite yet. Say back in plain words what my draft asks for. Name the reason I give and the action I want. List anything a reader can't find, like a missing price, date or reason. Step 2. Play my most important reader: [describe them, for example, my biggest customer]. Ask the 5 hardest questions they would ask. Do the money math from their side. Step 3. Point to the weakest sentences and say why each one is weak. Do not add any fact, number or reason I didn't give you. Step 4. Suggest 2 short ways to order the email. Explain each in one line. Step 5. List every number, date and promise in my draft. Confirm each one matches LOCKED FACTS, and flag anything that doesn't. I will write the final version myself. ``` Paste into any AI chat tool, then write the final email in your own words. ## Before you send it 1. Put the exact price, date and reason in the email, not "a modest increase." 2. Check every number and date against your own notes after each AI pass. 3. Do the customer's math, and call your biggest accounts first. 4. Read it out loud, and cut anything you wouldn't say on the phone. 5. When the new prices reach invoices, keep follow-ups polite with our [invoice payment reminders prompt](https://mcafax.com/notebook/prompts/invoice-payment-reminders). More owner prompts: [browse the MCAFax prompt library](https://mcafax.com/notebook/prompts). ## Questions readers ask **What tool does the original workflow use?** ChatGPT. The guest pastes in her own rough draft and asks follow-up questions in the same chat. **Why did the first AI version add a fake number?** A request to make something "more compelling" invites the AI to add proof. If you don't give it a real number, it may make one up. **What is a skeptic pass?** A follow-up that asks the AI to find weak claims, missing evidence and the questions a doubtful reader would ask, without rewriting anything. **Should I let AI write my customer emails for me?** Use it to find gaps and test your reasons, then write the final words yourself. You're the one the customer will call. **How do I stop the AI from changing my prices or dates?** List them as locked facts at the top of the prompt, and check each one again after every pass. **Is it safe to paste customer details into an AI tool?** Leave out names, account numbers and anything private. The draft works fine with "my biggest cafe" in place of a name.