Quickstart

import { generateText, isStepCount } from 'ai';
import { buyFor } from './agentcard';

const histories = new Map<string, any[]>(); // each shopper's earlier messages

export async function answer(shopperId: string, message: string) {
  const turn = buyFor(shopperId).turn(message, {
    sendLink: (link) => deliverLink(shopperId, link), // your code
  });
  const messages = turn.messages(histories.get(shopperId));
  const result = await generateText({
    model: yourModel, // the model you already use
    tools: { buy: turn },
    stopWhen: isStepCount(10), // lets the model read the tool's answer and reply
    messages,
  });
  histories.set(shopperId, [...messages, ...result.responseMessages]); // the next turn starts from here
  return result;
}

import OpenAI from 'openai';
import { buyFor } from './agentcard';

const openrouter = new OpenAI({ baseURL: 'https://openrouter.ai/api/v1', apiKey: process.env.OPENROUTER_API_KEY });
const histories = new Map<string, OpenAI.ChatCompletionMessageParam[]>(); // each shopper's earlier messages

export async function answer(shopperId: string, message: string) {
  const turn = buyFor(shopperId).turn(message, {
    sendLink: (link) => deliverLink(shopperId, link), // your code
  });
  const messages = turn.messages(histories.get(shopperId)) as OpenAI.ChatCompletionMessageParam[];
  const send = async () =>
    (await openrouter.chat.completions.create({ model: 'anthropic/claude-opus-5.5', messages, tools: [turn.openai] })).choices[0].message;

  let reply = await send();
  while (reply.tool_calls?.length) {
    messages.push(reply);
    for (const call of reply.tool_calls) {
      if (call.type !== 'function') continue;
      // turn.handle returns the JSON the model reads, with every link taken out.
      const content = await turn.handle(call.function.arguments).catch((error) => error.message);
      messages.push({ role: 'tool', tool_call_id: call.id, content });
    }
    reply = await send();
  }
  histories.set(shopperId, [...messages, reply]); // the next turn starts from here
  return reply.content; // the model's answer for the shopper
}