Workers AI response

When creating a simple fact generator, I configured it in such a way that the user doesn’t need to ask a question. For example, it’s like a website that generates a new fact every time it’s visited. However, the problem I’m facing is that it generates the same fact every time. How can I introduce randomness into this process?

import { Ai } from './vendor/@cloudflare/ai.js';

export default {
  async fetch(request, env) {
    const ai = new Ai(env.AI);

    let chat = {
      messages: [
        { role: 'system', content: 'You are a friendly assistant.' },
        { role: 'user', content: 'Tell me a fact' }

    const response = await'@cf/meta/llama-2-7b-chat-int8', chat);

    return Response.json(response);