Vibe Coding Invents Your Pricing. Your Marketing Site Needs a Source of Truth

If you scroll X this week, the vibe-coding argument is still going. One camp says it gets you a demo, not a product. Another jokes that you are too scared to touch the output because everything might break. A quieter complaint is more useful if you are trying to ship a marketing site: a lot of current vibe-coding tools have no source of truth.

That last gap is what blows up after launch.

You paste a one-line brief into a chat. The model returns a polished homepage, a pricing table, three testimonials, and a line about thousands of happy customers. It looks shippable. Then you notice the monthly plan is a number you never provided. The quoted company does not exist. The feature list includes a dashboard you have not built.

The site runs. The facts are fiction.

The failure is architectural, not a bad prompt

A coding agent is excellent at producing markup and components. It is not automatically excellent at remembering what is true about your business.

In a typical vibe-coding loop it goes like this:

1. You describe the company in a prompt.
2. The model fills every gap so the page looks complete.
3. You tidy typography, spacing, and the hero.
4. You start a new chat, or the context window rolls over.
5. The next page — or the next edit — invents a slightly different version of the same company.

There is no durable record of the legal name, the offers, the prices, the claims you will and will not make, who can be quoted, and which URLs already exist. The chat is the database. Chats are a terrible database.

This is why "it runs" is not "it ships" for a marketing site. Shipping means a visitor, a journalist, or an AI answer engine can quote a sentence and you will still stand behind it next month.

Lock the facts before you generate the pages

Before you ask any AI website builder or coding agent to produce a homepage, write down a source of truth a human can review. Keep it boring and specific. If a field is unknown, mark it unknown. A blank section is safer than a fluent lie.

The minimum brief I now refuse to skip

• Legal and brand. Legal entity, public brand name, domain, locations, and the one sentence you use to describe what you sell.
• Offers. Each product or service in one paragraph, who it is for, and what it is not.
• Proof you can defend. Only testimonials, case studies, logos, and metrics you can point to a source for. If you cannot, the section stays empty.
• Commercial facts. Prices, plan names, what is included, what is not, and the refund or trial policy — or an explicit "contact us" if those are not public yet.
• Constraints. Claims the model must never invent: customer counts, awards, "trusted by" logos, performance numbers, invented case studies.
• URLs you already own and want to keep.

Fabricated specifics do not just fail to convert. They get quoted, and then corrected in public.

One knowledge base, many pages

Once those facts live outside the chat, page generation becomes a projection of a record, not a fresh improvisation.

That is the difference between prompting a homepage and operating a site:

• Change a price in one place, and every plan table can be updated from the same record.
• Add a second offer without rewriting the "about" story two different ways.
• Grow a campaign page into a multi-page site without inventing a new company on the services page.

If you are still deciding whether to launch one page or a small site, that choice is about traffic and offers, not about whether the facts are stable. We published a landing page vs website decision table for that call. The source of truth should be the same in either case. Launch on the URL you plan to keep, then add pages as sales and search questions show up.

A four-question test you can run on any tool

Ask the tool, or your own agent workflow, these questions before you trust it with a live domain:

1. Where are the business facts stored after the first prompt?
2. If I start a new chat, does it still know the approved price and the claims I forbade?
3. What does it do when it does not know a number — leave a gap, ask, or invent one?
4. When I correct a fact, do existing pages update from that correction?

If the only memory is the current thread, you do not have a website system. You have a demo generator.

Those questions sit next to the ownership and export checks in our guide to evaluating an AI website builder. The demo will always look fine. The source of truth is what you are left holding after the context window is gone.

What we do in PolyDraft, and what we do not claim

This post is written by the PolyDraft team, so here is the honest version.

When you describe the business or paste an existing public URL, PolyDraft turns your facts, products, goals, and media into a verified knowledge base — the source of truth for every page and later update. Copy is supposed to stay grounded in those reviewed facts. You inspect the complete preview, fix anything that is wrong, and approve what goes live. We do not invent customer results or traffic lifts, and a fact marked unknown should stay blank rather than become a statistic.

That is the product idea: an AI website builder that researches and builds from a record you can review, not from a disposable chat. Whether you start with one page or a full site, the facts should not have to be re-explained — or re-invented — each time you ask for a change.

If you are vibe-coding the site yourself, steal the same pattern. Keep a SOURCE_OF_TRUTH.md (or a small CMS collection) that every prompt is required to read, and treat any fact not in that file as out of bounds.

A short workflow you can use this week

1. Write the brief above. Have a second person who knows the business strike anything they cannot defend.
2. Decide landing page vs website, and reserve the URLs you want to keep.
3. Generate the first preview only after the brief is approved.
4. Reject any invented metric, logo, or quote on sight. Do not leave it to "fix later."
5. Make one factual change — a price, a service name — and confirm every affected page updates from the same record.
6. Only then publish.

Vibe coding can still be the fastest way to get a layout. It is a bad place to store the truth about a company.