app/api/langchain-tools/duckduckgo.ts

import { SafeSearchType, search } from "duck-duck-scrape";
import { convert as htmlToText } from "html-to-text";
import { Tool } from "langchain/tools";

export class DuckDuckGo extends Tool {
 name = "duckduckgo_search";
 maxResults = 4;

 /** @ignore */
 async _call(input: string) {
 const searchResults = await search(input, {
 safeSearch: SafeSearchType.OFF,
 });

 if (searchResults.noResults) {
 return "No good search result found";
 }

 const results = searchResults.results
 .slice(0, this.maxResults)
 .map(({ title, description, url }) => htmlToText(description))
 .join("\n\n");

 return results;
 }

 description =
 "a search engine. useful for when you need to answer questions about current events. input should be a search query.";
}