Every AI writing tool can produce a product description in ten seconds, and most of them produce the same one: “Elevate your everyday with our premium, thoughtfully crafted…” Merchants notice. Reviews of Shopify Magic and Sidekick alike say the copy is “rarely publish-ready without editing,” and the usual reaction is to give up on AI copy or to spend the time saved on rewriting.
The generic output is not a model problem. It is a missing-input problem. The tool has never been told what your store sounds like, who buys from you, or which words you would never use, so it defaults to the average of every store it has seen. Give it those three things once and the same tool writes copy that reads like you. This post shows how, with Sidekick, at the level of one product and then a whole catalog.
Why copy goes generic
Three inputs decide whether a description sounds like your store.
Voice. Not “friendly and professional”, which describes everyone, but the specific register: short sentences or long, jokes or none, “you” or “our customers”, British or American spelling, technical or plain. The best sellers you already wrote carry this; a tool that reads them first will match them.
Customer. A tee described for gift buyers leads with sizing confidence and presentation. The same tee for a repeat customer leads with the new colour. If the tool does not know who is reading, it writes for nobody.
Banned words. Every store has a list, whether written down or not. “Elevate”, “unleash”, “premium quality”, “game-changing”, “curated”, “seamless” and exclamation marks are on ours. A tool told to avoid them stops sounding like an advert.
Sidekick reads product data and can read your existing descriptions, so it can infer the first. It cannot infer the second or third. Tell it.
The one-time setup: a brand-voice skill
Save this once as a Sidekick skill and run it at the start of any content session:
Use this brand voice for everything you write in this conversation for [STORE NAME], which sells [PRODUCTS] to [TARGET CUSTOMER]. Tone: [THREE OR FOUR WORDS]. Write like a knowledgeable friend, not a brochure. Short sentences. Concrete nouns and numbers over adjectives. Say what the product does for the customer. Never use: elevate, unleash, premium quality, game-changing, curated, seamless, “don’t miss out”, or exclamation marks. Read two of our best-selling product descriptions first and match their vocabulary. Confirm in one line that the voice is set, then wait.
That is /brand-voice from the library. The “read two best sellers first” line is what makes it work: it anchors the tool to copy you already approved. Sidekick’s memory is per conversation and per user, so run it in each new chat, and share the skill link with anyone else who writes for the store so everyone’s Sidekick sounds the same.
A description structure that sells
Length is not the goal; answering the buyer’s questions in the order they ask them is. The structure we use for every product:
- Opening paragraph, 40 to 60 words, leading with the main benefit. What changes for the customer, not what the product is made of. Materials come next.
- Three to five bullets that turn features into benefits. “Heavyweight 220gsm cotton” becomes “220gsm cotton that holds its shape after fifty washes.” Each bullet one line.
- A “good to know” line. Sizing, care, what is in the box, delivery time. The line that prevents the support email.
- SEO title under 60 characters and meta description under 155. Written at the same time so the page is complete when it goes live.
The prompt that produces it:
Write product copy for [PRODUCT NAME] in our brand voice for [TARGET CUSTOMER]. Open the product and read its title, current description, options, variants, price and metafields. If a detail you need is missing, ask one question, then continue. Write: a first paragraph of 40 to 60 words leading with the main benefit; 3 to 5 bullets that turn features into benefits; a “good to know” line; an SEO title of at most 60 characters; a meta description of at most 155 characters including the product type. Show the draft and ask whether to update the product. Only after a clear yes, update the description, SEO title and meta description. Do not change price, tags or images. Do not invent specifications, certifications or materials.
That is /pdp-copy. Two guardrails in it matter more than the rest: “do not invent” stops the tool adding a certification you do not have, and “ask before updating” means nothing changes on the live product until you have read it.
What to feed it
Sidekick can read the product but not your photos in detail. Anything visual that matters, such as the exact shade, the texture or how it drapes, goes in your answer when it asks, or in the placeholder. If the product came from a supplier with a spec dump, paste the spec and say “use only facts from this.” If the product is personalized or made to order, say so; it changes the “good to know” line and the delivery promise.
Rewriting a whole catalog without losing consistency
One description at a time is fine for launches. For a catalog of two hundred products that all sound like the supplier wrote them, you need a process, not a prompt.
Start with titles. Inconsistent titles make every description harder. /bulk-titles proposes one naming pattern, shows it on five real products, and lists every rename for approval before changing anything. Handles stay the same so links keep working.
Set the voice, then work by collection. Run /brand-voice, then /pdp-copy through one collection at a time, approving each. Collections keep the vocabulary consistent because similar products are written in sequence.
Do twenty, then read ten as a customer. The tenth description will sound like the first if the voice skill is doing its job. If it drifts, tighten the banned-words list and continue.
Add FAQs to the products that generate questions. /product-faq writes five to eight real questions from the product data and your policies, and marks anything it cannot answer as CONFIRM so you fill the gap instead of the tool guessing.
Finish with the SEO fields you skipped. /meta-tags lists what is empty and writes options with character counts.
Magic or Sidekick for this?
Shopify Magic’s sparkle button in the product editor is faster for one blank description while you are already on the page, and it now takes brand-voice settings. Sidekick is better for anything that needs consistency across many products, a customer in mind, or the SEO fields done in the same pass. Most merchants use both; the Sidekick vs Magic comparison lays out when.
A before and after
Supplier copy: “Premium quality cotton t-shirt. Comfortable and stylish. Available in many colours. Perfect for any occasion!”
After /brand-voice and /pdp-copy for a gift buyer: “A tee that still fits after a year of washing. 220gsm organic cotton, pre-shrunk, with a neckline that holds its shape. Made to order in three days and shipped in a box you would happily hand over. Sizes run true; if in doubt, size up. Free returns for 30 days.”
Same product, same tool. The difference is that the second one was told who it was writing for and what not to say. That is the whole trick, and it takes one saved skill.
Mistakes to avoid
Letting the tool invent facts. The single biggest risk of AI product copy is a claim you cannot back: a certification, a material, a country of origin. The “do not invent” guardrail in the prompt handles most of it; you still read every draft before approving, because you are the one who has to honour the claim.
Writing for search engines first. Keyword-stuffed descriptions read badly and, since 2026, convert worse than plain ones with AI shopping assistants quoting product pages to buyers. Write for the person, put the product type and main phrase in the SEO title, and let the description be readable.
One voice for every audience. A wholesale catalog and a gift-buyer product page should not sound the same. Save a second brand-voice skill, /brand-voice-b2b, for trade communications, and switch between them.
Skipping the “good to know” line. That line answers the question that otherwise arrives as a support message. Sizing, care, what is in the box, delivery time: if customers ask it, it belongs on the page.
Rewriting everything at once without reading. Twenty at a time, then read ten as a customer. If the twentieth sounds like the first, continue; if it has drifted, fix the voice skill before the next batch.