AI Guides › Step-by-step guides
By Nigel Guy · 8 min read
Most people open an AI app builder, type one excited sentence and press enter. Something appears within a minute — screens, buttons, a login box — and it feels like progress. It is a demo: the builder guessed what data you need, who can see it and what you charge for, and every guess is now baked into code you will spend credits unpicking. The builder was never the weak link; the missing plan was.
The rule: no build prompt until you have a written build brief that a stranger could build from — screens, data, access and money, with the scope already cut.
This guide uses Claude to write and stress-test that brief, then Blink (blink.new) to build from it. Blink's own documentation recommends the same order: its reference page on Agent and Plan modes says "plan first, build second".
| You need | Cost at time of writing | Notes |
|---|---|---|
| A Claude account (claude.ai) | Free plan works; Pro is $20 a month billed monthly (roughly £15 before VAT) | Pricing page shows US dollars; check the UK price at checkout |
| A Blink account (blink.new) | Free: 5 credits a day, capped at 30 a month | Free gives you a preview URL only — no production publishing |
| Blink Starter | $25 a month (roughly £19) | Needed to publish to production and use a custom domain |
| Blink Pro | $50 a month (roughly £37) | Blink's docs list server-side APIs, webhooks and in-app code editing at Pro and above |
| A Stripe account | Stripe charges per transaction, not a subscription | Only if your app takes payments |
Blink bills in US dollars; check its pricing page before you commit.
Open a new chat in Claude and paste this prompt.
You are a product planner who writes specifications for no-code AI app builders. I am not a developer.
My app idea: [ONE SENTENCE DESCRIBING THE APP]
Who will use it: [TYPE OF USER]
How I plan to charge, if at all: [FREE / ONE-OFF PAYMENT / SUBSCRIPTION / NOT SURE]
Goal: a written build brief, not code, that an AI app builder could follow without asking me anything.
Work in this order:
1. If anything above is missing or vague, ask me up to five short questions first and wait for my answers. Do not guess.
2. List every screen, in the order a new user meets them, with what the user sees and does on each.
3. List the data to store: one table per kind of thing, its fields with types, and how tables link to each other.
4. Mark each screen and each table as public, signed-in only, or owner-only (a user sees only their own records).
5. State whether payments are needed, which kind, and exactly what a payment unlocks.
6. Define the smallest first version that is still genuinely usable. Move everything else to a "Later" list.
Output format: Markdown with the headings Screens, Data, Access, Payments, First version, Later. Use plain English and tables where they help.
Before you reply, check: does every screen use data defined in Data? Does every table have an access rule? Have you moved anything non-essential to Later? Fix any gaps first.
Fill in: your idea, your user and your charging model in the three brackets.
A brief written in one pass usually skips the unglamorous cases. In the same chat, run this:
Act as a sceptical reviewer of the build brief above. Your job is to find what will break once real people use it.
Check for, and list under each heading:
- Missing states: empty lists, failed payments, cancelled subscriptions, deleted accounts, forgotten passwords.
- Access mistakes: any place one user could see or change another user's data.
- Scope creep: anything in First version that is not needed for [THE ONE THING A USER MUST BE ABLE TO DO].
- Ambiguity: any sentence an app builder could reasonably read two ways.
Then produce a revised brief in the same format, with a short "Changes" list at the top. If a fix depends on a decision only I can make, ask me rather than choosing for me.
Fill in: the single action that makes your app worth opening.
Save the final brief somewhere outside both tools — a document or note. It is now your source of truth.
Sign up at blink.new (no card is needed for Free). Before you send anything, find the Agent/Plan toggle in the toolbar below the input box and switch to Plan — it shows a green glow. Plan mode answers and designs without writing code, and Blink says it costs significantly less than Agent mode. (Some older Blink help pages call this Chat mode.)
Paste the brief, or attach it as a file, with this:
This is the build brief for a new app. Do not build anything yet.
1. Restate the app in three sentences so I can confirm you have understood it.
2. Propose the database tables and fields you would create, and say which column identifies the record's owner.
3. List any part of the brief you find unclear or contradictory, and ask me about each one.
4. Propose the order you would build it in, smallest working slice first.
Wait for my confirmation before switching to building.
Correct anything it gets wrong now, while it is cheap.
Flip the toggle to Agent (or say "go ahead" and approve the switch card Blink shows). Build in this order, one prompt per slice, checking the preview at your *.sites.blink.new address after each:
Blink's prompting guide recommends building by component, not all at once. To see what a message cost, click the info icon on the AI's reply. Every completed task creates a version; the clock icon in the chat panel (or Project Settings → Versions) lets you restore an earlier one if a slice goes wrong.
Do not take "it has a login" as proof the data is private. In Blink, go to Workspace Settings → Security:
owner_id instead of user_id, set it here.Never paste a secret key (blnk_sk_...) into the chat or into front-end code; Blink's security page says it bypasses all security rules.
Ask Agent mode to add Stripe using the Payments section of your brief, word for word. Blink's SaaS guide says to walk the whole journey in Stripe test mode first: hit the paid limit, upgrade, and confirm the feature unlocks without a page refresh, then check the "Manage Subscription" link opens Stripe's customer portal.
I could not confirm Blink's exact menu path for connecting a Stripe account from its public docs at time of writing, so follow the steps Blink gives you in the editor, and ask it in Plan mode which keys go where before you paste anything.
When the preview behaves, click Publish (top right). The first publish asks you to choose an expected monthly traffic tier. Production needs Starter or above.