pref0 + Vercel AI SDK

import { streamText } from "ai";
import { openai } from "@ai-sdk/openai";

const PREF0_API = "https://api.pref0.com";
const PREF0_KEY = process.env.PREF0_API_KEY!;

async function getPreferences(userId: string) {
  const res = await fetch(`${PREF0_API}/v1/profiles/${userId}`, {
    headers: { Authorization: `Bearer ${PREF0_KEY}` },
  });
  const { preferences = [] } = await res.json();
  return preferences
    .filter((p: any) => p.confidence >= 0.5)
    .map((p: any) => `- ${p.key}: ${p.value}`)
    .join("\n");
}

export async function POST(req: Request) {
  const { messages, userId } = await req.json();
  const learned = await getPreferences(userId);

  const result = streamText({
    model: openai("gpt-4o"),
    system: `You are a helpful assistant.\n\nLearned preferences:\n${learned}`,
    messages,
  });

  return result.toDataStreamResponse();
}