4. Answer from policies

import {
  Agent, InMemoryVectorStore, KnowledgeBase, OpenAIEmbedding, openai,
} from "@agentium/core";

const knowledge = new KnowledgeBase({
  name: "Store policies",
  vectorStore: new InMemoryVectorStore(new OpenAIEmbedding()),
});
const agent = new Agent({
  name: "support",
  model: openai(process.env.OPENAI_MODEL ?? "gpt-6.1-sol"),
  instructions: "Search store policies before answering. Cite document IDs. If evidence is missing, say so.",
  tools: [knowledge.asTool({
    toolName: "search_policies",
    topK: 2,
    formatResults: (results) => results.map((item) => `[${item.id}] ${item.content}`).join("\n\n"),
  })],
});

try {
  await knowledge.addDocuments([
    { id: "returns", content: "Unopened items can be returned within 30 days of delivery. Refunds require staff approval." },
    { id: "shipping", content: "Standard shipping takes 3–5 business days. Order tracking provides the delivery estimate." },
  ]);
  const result = await agent.run("Can I return an unopened item after 14 days?");
  if (result.status !== "completed") throw new Error(`Run ended: ${result.status}`);
  console.log(result.text);
} finally {
  try { await agent.close(); } finally { await knowledge.close(); }
}