Write once, sound like you: an AI prompt pack for product descriptions and captions

What you'll have in fifteen minutes: a small set of copy-paste prompts that turn a few facts about a product into a clean, on-brand description — and a month of social captions from a single instruction — written in your voice, not robot-brochure voice. No subscription, no design skills, no "content strategy" course.

This is the chore a Singapore owner already reaches for AI to solve — "we always try 'free' stuffs to experiment. Example chatgpt to do write up on product description" (r/askSingapore, Nov 2025) — and merchants elsewhere say the same: product descriptions "used to take up so much of my time" (Shopify merchant review, May 2026). The trick isn't the AI; it's giving it the right instructions so the output sounds like you and doesn't need a rewrite.

Is this for you?

Build it if you sell products online, run social accounts, or write the same kind of blurb again and again and dread it. Skip it if you have a copywriter you trust — though even then these prompts make a decent first draft. This is prompts, not plumbing: there's nothing to switch on and nothing that can break.

What it costs

S$0. Free ChatGPT or free Google Gemini will do everything here. Canva's free plan turns captions into posts if you want visuals (Canva pricing — re-check the free-plan limits, they change). No credit card needed to start any of them. One honest caveat, the same as any free AI tool: don't paste anything confidential, because free tiers may use your inputs to improve the model (see "Your data").

Before you start (2 minutes)

Open free ChatGPT or Gemini — either works; use whichever you already have. That's the whole setup.

Build it, step by step

Step 1 — Teach it your voice (5 minutes, do this once)

This is the step everyone skips and then complains the output is generic. Paste this first:

Here are two things I've written for my business. Study the tone, then wait for my next message. [paste 1–2 of your own good descriptions or posts]

If you have nothing written yet, describe your voice instead: "friendly, plain-spoken, a little cheeky, no marketing buzzwords, Singaporean English is fine."

Step 2 — The product-description prompt (fill in the blanks)

Write a product description for my [type of business] in the voice above. Product: [name]. Facts: [3–5 true bullet points — material, size, who it's for, price, one nice detail]. Keep it under [80] words. Don't invent features I didn't give you. Give me two versions: one warm, one punchy.

Step 3 — A month of captions from one prompt

Give me 20 social captions for [business], in my voice, for [Instagram]. Mix these types: product spotlight, behind-the-scenes, a customer question answered, a light promotion, a local/Singapore seasonal hook. Each under 30 words, with 3 relevant hashtags. No emojis unless they fit naturally.

Step 4 — Turn one post into five (repurpose)

Take this [caption/testimonial/blog paragraph] and rewrite it for: an Instagram caption, a WhatsApp broadcast, a Google Business Profile post, and a short email to my list. Keep my voice; adjust the length and tone for each.

Drop any caption into a free Canva template if you want a matching image.

Test it works (2 minutes)

Run Step 2 on one real product. You should get a description you'd actually use with only light edits. If it reads like a generic brochure, you skipped Step 1 — go feed it your voice and try again.

When it doesn't

• It sounds generic or samey. You didn't give it your voice (Step 1) or enough specific facts. The more true detail you hand it, the less it pads with fluff.
• It invents features your product doesn't have. AI will happily make things up. Only give it true bullet points, and always read before you publish — you're the editor, it's the intern. This matters most for anything about safety, ingredients, or claims.
• Everything comes out too long. Add a hard limit ("under 50 words") and ask for "no preamble, just the description."

Your data

You're pasting product info, not usually personal data, so the PDPA risk is low here. But the same free-AI catch from the receipt playbook applies: on free tiers, these tools may use what you type to improve their models, and a reviewer could see it. So don't paste anything confidential — supplier costs, unreleased plans, customers' personal details. Product facts and public marketing copy are fine.

Switch it off

There's nothing to switch off — these are just prompts you use when you want them. Keep the ones that work in a note; ignore the rest.

What's next

Grab the full prompt pack — it's the first free download in our template library, with a few more prompts than fit here (FAQ answers, review replies, a "rewrite this so it's clearer" fixer). Use it on your ten best-selling products this week. Then, if writing the same customer answers is also eating your time, the WhatsApp quick-replies playbook is the natural next win.

---