🆕 程式碼

1. src/day24_qrewrite.js
   // src/day24_qrewrite.js
   import { openai } from "./aiClient.js";
   import { answerWithRAG } from "./day16_rag_store.js";

/**

• 查詢重寫：給定原始問題，產生 3–5 個等價或相關問法
  */
  export async function rewriteQueries(originalQ) {
  const res = await openai.chat.completions.create({
  model: "gpt-4o-mini",
  temperature: 0.3,
  messages: [
  { role: "system", content: "你是查詢重寫器，請將問題改寫成多個等價問法，維持原意。" },
  { role: "user", content: 問題：${originalQ}\n請輸出一個 JSON 陣列，例如 ["問法1","問法2",...]，不要多餘說明。 }
  ]
  });
  try {
  return JSON.parse(res.choices[0].message.content);
  } catch {
  return [originalQ];
  }
  }

/**

• Query Rewrite 檢索：多路召回 + 去重
  */
  export async function retrieveWithQRewrite({ tenant, ns, query, topK = 6 }) {
  const queries = await rewriteQueries(query);
  const seen = new Map();
  const results = [];

for (const q of queries) {
const { sources } = await answerWithRAG({ tenant, ns, query: q, topK });
for (const s of sources) {
if (!seen.has(s.id)) {
seen.set(s.id, s);
results.push(s);
}
}
}

// 按 score 排序，取前 topK
results.sort((a, b) => (b.score || 0) - (a.score || 0));
return results.slice(0, topK);
}

2. app/api/kb/[tenant]/[ns]/ask/route.js（新增策略）

只貼新增的分支，保留 Day 19 / 23 的 default & section 分支：

import { retrieveWithQRewrite } from "../../../../../src/day24_qrewrite.js";

...

if (strategy === "qrewrite") {
const chunks = await retrieveWithQRewrite({ tenant, ns, query: q, topK: 6 });
const ctxText = chunks.map((h,i)=># 片段${i+1}（${h.docId}｜${h.id.split("#")[1]}）\n${h.text}).join("\n\n");

const res = await openai.chat.completions.create({
  model:"gpt-4o-mini", temperature:0.2,
  messages:[
    { role:"system", content:"你是嚴謹的客服知識庫助理，僅依據提供片段回答；不足請說明。" },
    { role:"user", content:`問題：${q}\n\n片段：\n${ctxText}\n\n請用繁體中文回答。` }
  ]
});
const answer = res.choices?.[0]?.message?.content?.trim() || "沒有找到足夠資訊。";

return NextResponse.json({ ok:true, strategy:"qrewrite", answer, sources: chunks });

}

3. app/studio/page.tsx（新增策略選項）
   <select className="select select-bordered select-sm" value={strategy} onChange={e=>setStrategy(e.target.value as any)}>