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Vibe codingHardvc-g509
Subject Ai code reviewLevel Senior–Staff~20 minCommon in Networking & APIs interviewsIndustries Software development, Technology

Question

An AI agent wrote this SQS-triggered Lambda (TypeScript) to charge customers from an order queue. Finance reports occasional duplicate charges. The code looks correct. Find the root cause and the fix.

ts
export const handler = async (event: SQSEvent) => {  for (const record of event.Records) {    const order = JSON.parse(record.body);    await stripe.charges.create({      amount: order.amountCents,      currency: "usd",      customer: order.customerId,    });    await db.orders.update({ id: order.id }, { status: "charged" });  }};
What a strong answer looks like

Treat the AI’s output as a draft to verify, not an answer to trust. Name the specific flaw and the input that triggers it, say how you’d catch it — tests, edge cases, reading critically — and how you’d re-prompt or decompose to get it right.

Learn the concepts
Describe your solution

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.