Web Search as a Tool in the Vercel AI SDK

// lib/tools.ts — server-only
import { tool } from "ai";
import { z } from "zod";

export const webSearch = tool({
  description:
    "Search the live web. Use for news, prices, and anything published " +
    "after your training cutoff. Write the query in plain words.",
  inputSchema: z.object({
    query: z.string().describe("Plain-language search query"),
    countryCode: z
      .string()
      .length(2)
      .optional()
      .describe("ISO country code to localise results, e.g. US or GB"),
  }),
  execute: async ({ query, countryCode }) => {
    const res = await fetch("https://www.apipick.com/api/search/web", {
      method: "POST",
      headers: {
        "x-api-key": process.env.APIPICK_KEY!,
        "content-type": "application/json",
      },
      body: JSON.stringify({
        query,
        max_num_results: 5,
        ...(countryCode ? { country_code: countryCode } : {}),
      }),
    });
    if (!res.ok) return { error: `search failed: ${res.status}` };
    const data = await res.json();
    return data.results.map((r: any) => ({
      title: r.title,
      url: r.url,
      snippet: r.snippet,
    }));
  },
});

import { generateText, stepCountIs } from "ai";
import { webSearch } from "@/lib/tools";

const { text, steps } = await generateText({
  model: "anthropic/claude-sonnet-5",
  tools: { webSearch },
  stopWhen: stepCountIs(5),        // <- the fix
  system:
    "Ground factual claims in search results and cite the URL. " +
    "If search returns nothing useful, say so rather than guessing.",
  prompt: "What changed in the EU AI Act timeline this year?",
});

// app/api/chat/route.ts
import { streamText, stepCountIs, convertToModelMessages } from "ai";
import { webSearch } from "@/lib/tools";

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

  const result = streamText({
    model: "anthropic/claude-sonnet-5",
    messages: convertToModelMessages(messages),
    tools: { webSearch },
    stopWhen: stepCountIs(5),
    system: "Cite the URL for every factual claim.",
  });

  return result.toUIMessageStreamResponse();
}

export const readPages = tool({
  description:
    "Fetch clean readable text for specific URLs. Call after webSearch " +
    "when a snippet is not enough to answer.",
  inputSchema: z.object({
    urls: z.array(z.string().url()).min(1).max(3),
  }),
  execute: async ({ urls }) => {
    const res = await fetch("https://www.apipick.com/api/extract", {
      method: "POST",
      headers: {
        "x-api-key": process.env.APIPICK_KEY!,
        "content-type": "application/json",
      },
      body: JSON.stringify({ urls }),
    });
    if (!res.ok) return { error: `extract failed: ${res.status}` };
    const data = await res.json();
    return data.results
      .filter((r: any) => r.status === "ok")
      .map((r: any) => ({ url: r.url, content: r.content.slice(0, 6000) }));
  },
});