Full code straight from the tutorial

import { Ai } from '@cloudflare/ai'

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

        const answer = await ai.run(
            '@cf/meta/llama-2-7b-chat-int8',
            {
                inputs: [
                    { role: 'user', content: `What is the square root of 9?` }
                ]
            }
        )

        return new Response(JSON.stringify(answer))
    }
}