Prompt · Writing
Product description prompt
Producing listing copy at volume where an invented feature is a returns problem and, in several jurisdictions, a legal one.
Write a product description.
<facts>
{{facts}}
</facts>
Audience: {{audience}}
Length: {{length}} words.
Rules:
- Use only the facts above. Do not add features, materials, certifications, compatibility claims or origin. If a fact is absent, it does not exist.
- Lead with the problem it solves, not with the product name.
- Turn each specification into what it means for the buyer — but only where the fact supports the claim. "IP67" becomes "survives being dropped in a sink"; it does not become "indestructible".
- One concrete detail beats three adjectives.
Never use: revolutionary, game-changing, cutting-edge, seamless, elevate, unleash, must-have, perfect for anyone.
If the facts are too thin to write {{length}} words honestly, write less and list what you would need. Do not pad.What to fill in
{{facts}}- Specifications, materials, dimensions, what it does. Bullet points are fine. The output can only be as good as this list is complete.
{{audience}}- Who buys it and what they compare it against.
{{length}}- A number. 60 for a listing, 150 for a page.
Why it is written this way
Every rule in the prompt is there because of a specific failure it prevents. Knowing which is which is what lets you adapt it instead of only pasting it.
The fact constraint is the whole prompt
Commerce copy is where invention is most expensive. A model that adds "dishwasher safe" because it fits the rhythm creates returns, complaints and, in the EU, a misleading-commercial-practice exposure. Everything else here is optimisation; this rule is the product.
The banned list is literal
These words appear because they are the highest-probability continuations, not because they describe anything. Naming them specifically works far better than asking for "no marketing fluff", which the model will agree to and then ignore.
Benefit translation is bounded
"Turn specs into benefits" alone licenses exaggeration. Adding "only where the fact supports the claim" keeps the useful transformation and removes the overreach.
Short is allowed
A word count with thin facts is an instruction to invent. Permission to under-deliver and say why converts a fabrication into a content gap you can fill.
The version most people write, and what it costs
Write an engaging product description for: {{facts}}"Elevate your everyday routine with this game-changing essential." It invents a feature or two to reach a satisfying length, uses every banned word, and describes a product category rather than this product. At scale you get a thousand listings that could be swapped between products without anyone noticing.
What it still gets wrong
- It cannot verify your facts. Wrong input produces confidently wrong copy.
- Regulated categories — health claims, supplements, financial products, cosmetics — need review against the specific rules of each market. No prompt substitutes for that.
- At volume, output converges. Vary the fact ordering and emphasis or a hundred descriptions will share a structure.
Check it before you ship it
- Prompt LinterStructural review of a prompt: what is costing you money and what will fail.
- Few-Shot Example FormatterPairs in, formatted examples out. Four formats, priced.
- LLM API Cost CalculatorRequests per month in, dollars out. Input, cached input and output priced separately.
To build one of these from scratch for a task not covered here, the prompt generator assembles the same structure — delimiters, output contract, edge cases — from an expert-authored blueprint, and the prompt review checklist is what to run over the result.