Chapter 8 of 15

How to stop the AI from inventing prices in customer service

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Blocking made-up prices, promised deadlines and discounts.

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CertuAI free manual · Updated September 23, 2026 · Written by Bernardo Villela, CEO of CertuAI · see the whole manual

Summary in 3 facts

Short answer Three layers: a clear instruction in the business text, a check in your code before sending and a handoff to a person when the subject is money outside the price list.
Instruction with an exit: "if the price is not on the list, say you will confirm and write <<CHAMAR HUMANO>>".
Check in the code: a price outside the table never reaches the customer.

How do you stop the AI from inventing a price or promising a deadline?

Short answer

Three layers: a clear instruction in the business text, a check in your code before sending and a handoff to a person when the subject is money outside the price list.

The three layers

Instruction with an exit: "if the price is not on the list, say you will confirm and write <<CHAMAR HUMANO>>".
Check in the code: a price outside the table never reaches the customer.
A person for every expensive question. Promise a callback, never a price.

src/index.jsjavascript

const PRECOS_PERMITIDOS = ['80', '120', '250']; // os mesmos do texto do negocio

function respostaSegura(texto) {
  const valores = texto.match(/R\$\s?([\d.]+)/g) ?? [];
  for (const bruto of valores) {
    if (!PRECOS_PERMITIDOS.includes(bruto.replace(/[^\d]/g, ''))) return false;
  }
  return !/desconto|abatimento|fa[cç]o por|deixo por/i.test(texto);
}

Where people get burned

Don't ask the AI to judge whether it can answer. The check lives in the code.

Frequently asked question

Which temperature should you use?

Between 0.3 and 0.5. Above 0.8 the AI starts inventing things.

And where CertuAI comes in

CertuAI already comes with this check built in.

Build an agent for free

Continue the manual

In short

The three layers that stop an AI agent from inventing a price, promising a deadline or giving a discount: instruction, a check in the code and a handoff to a human.