The Exact Prompts I Use to Go From Idea to Live Product in a Weekend

Act as a skeptical, well-informed critic of this idea: [describe idea in 2-3 sentences]. Tell me: who already solves this problem, how well, and what would make someone switch from what they use now. Then tell me the three most likely reasons this fails within 6 months. Don't soften it and don't suggest fixes yet — just tell me if this is worth building.

I'm building [one-sentence description]. Scaffold the smallest possible version that proves the core flow works end to end — the main thing a user does, and nothing else. Use [Next.js + Vercel, or your stack]. Skip auth, skip styling, skip edge cases. I want to be able to click through the main flow today.

Add [auth / a Postgres schema for X / Stripe checkout — pick what's next] to this app. Walk me through what you're adding and why before you write it, then implement it. Flag anywhere you're making an assumption about how I want this to work instead of just picking one silently.

You are a security engineer trying to break into this app, not review it politely. Go after auth, session handling, payment logic, and anything that touches another user's data. Assume I made mistakes. List every way you could get in, escalate access, or avoid paying that shouldn't be possible, ranked by severity, with the exact fix for each.

Set up Stripe so a customer can subscribe, upgrade, downgrade, cancel, and get refunded without emailing me. Handle the webhook events for subscription status changes and keep the database in sync. Tell me what happens if a webhook fails or arrives out of order.

Here's what changed in the app this week: [list]. Here's what I noticed users doing that I didn't expect: [list, or "nothing yet"]. What's the highest-risk thing in this app right now that I haven't tested?