Polish naver-news: preflight, link canonicalization, /health docs (#143)

Address the three non-blocking items flagged in the round 1/2 reviews. All were explicitly deferred by the reviewer as "follow-up if the maintainer wants" — picking them up now so the feature lands with a tighter surface. 1) Preflight 400 for start + display - 1 > 1000 Naver's official news endpoint only exposes the first 1000 items (start 1..1000, display 1..100). Asking for start=1000 & display=100 would send a request that silently returns no usable items, wasting an upstream quota call. Reject the combination before calling upstream with a 400 bad_request and a message that tells the caller which item the request would have needed and what the cap is. Boundary values (start + display - 1 === 1000) are still accepted. 2) Canonical link dedup The previous dedup key was link.toLowerCase(), which failed to merge the same article when Naver's redirect URLs differed only by query-param order, trailing slash, host-name casing, or fragment. Added canonicalizeLinkForDedup() which parses the URL, sorts search params by key, strips a single trailing pathname slash, drops the fragment, and lowercases the result — conservative on purpose so different paths or different query values stay as distinct articles. The visible items[].link value is still the original URL returned by Naver; only the dedup key is canonicalized. 3) Clarify the naverSearchApiConfigured vs naverNewsApiConfigured split The two flags currently evaluate the same boolean, but their semantic contracts differ: naverSearchApiConfigured reports "are the Naver Open API keys configured" (which is advisory for the shopping route since shopping has a BFF fallback), while naverNewsApiConfigured reports "is the news route operational end-to-end" (no fallback — 503 when false). Hoist the shared expression into a local, and add a `/health 업스트림 플래그 의미` section to packages/k-skill-proxy/README.md documenting the split. Also update naver-news-search SKILL.md and docs/features/naver-news-search.md to mention the new preflight and the canonical-link dedup behavior. TDD verification: added 4 new node:test cases exercising the boundary, overflow, and URL-dedup paths; ran the full k-skill-proxy workspace suite (202/202 pass) plus the root `npm run ci` (exit 0). Manual QA on a proxy started from this commit reproduces every round-1 case plus the new preflight: start=1000 & display=100 → 400 bad_request before upstream; start=1000 & display=1 and start=901 & display=100 → 503 (or 200/401 depending on keys), confirming the boundary passes preflight.
2026-06-24 02:04:11 +00:00 · 2026-04-22 13:17:51 +09:00 · 2026-04-22 13:17:51 +09:00 · 71d577b24d
commit 71d577b24d
parent ffcd8a5a13
7 changed files with 260 additions and 39 deletions
--- a/.changeset/naver-news-search.md
+++ b/.changeset/naver-news-search.md
@ -2,4 +2,4 @@
 "k-skill-proxy": minor
 ---

-Add `/v1/naver-news/search` route plus matching `naver-news-search` skill. Proxies the official Naver Search Open API news endpoint (`openapi.naver.com/v1/search/news.json`), reuses the existing `NAVER_SEARCH_CLIENT_ID`/`NAVER_SEARCH_CLIENT_SECRET` credentials, and keeps the user-facing credential surface empty ("불필요"). Strips `<b>` highlight tags and decodes HTML entities in titles/descriptions, parses RFC822 `pubDate` into ISO-8601, deduplicates results by `link`, caches successes for 5 minutes (failures are not cached), and exposes `naverNewsApiConfigured` on `/health`. Closes #143.
+Add `/v1/naver-news/search` route plus matching `naver-news-search` skill. Proxies the official Naver Search Open API news endpoint (`openapi.naver.com/v1/search/news.json`), reuses the existing `NAVER_SEARCH_CLIENT_ID`/`NAVER_SEARCH_CLIENT_SECRET` credentials, and keeps the user-facing credential surface empty ("불필요"). Strips `<b>` highlight tags and decodes HTML entities in titles/descriptions, parses RFC822 `pubDate` into ISO-8601, deduplicates results by canonicalized `link` (query-param order, trailing slash, host casing and fragments are ignored; different paths or query values are preserved), caches successes for 5 minutes (failures are not cached), and exposes `naverNewsApiConfigured` on `/health`. The route rejects `start + display - 1 > 1000` with a `400 bad_request` preflight before calling upstream, so requests outside Naver's 1000-item search window fail fast with a clear message instead of returning empty results. Closes #143.
--- a/docs/features/naver-news-search.md
+++ b/docs/features/naver-news-search.md
@ -38,7 +38,7 @@ description: k-skill-proxy 경유 네이버 검색 Open API 뉴스 검색으로
 | --- | --- | --- | --- |
 | `q` / `query` / `keyword` | string | (필수) | 검색어. 2글자 이상 |
 | `display` / `limit` / `size` | int | 10 | 반환 건수. 1 ~ 100 으로 clamp |
-| `start` / `offset` | int | 1 | 검색 시작 위치(1-indexed). 최대 1000 |
+| `start` / `offset` | int | 1 | 검색 시작 위치(1-indexed). 최대 1000. `start + display - 1 > 1000` 이면 proxy 가 업스트림 호출 전에 `400 bad_request` 로 거절 |
 | `sort` | string | `sim` | `sim`(관련도순) 또는 `date`(최신순). 그 외 값은 `sim` fallback |

 ## 기본 호출
@ -125,7 +125,8 @@ curl -fsS --get 'http://127.0.0.1:4020/v1/naver-news/search' \

 - 사용자 요구가 "오늘", "최신" 이면 `sort=date` 로 호출하는 것이 보통 더 만족스럽다.
 - `display` 가 클수록 네이버 API 쿼터를 빨리 소모한다. 기본 10 에서 벗어날 필요 없는 경우가 많다.
- `start + display` 조합이 1000 을 넘는 위치는 네이버 API 가 결과를 돌려주지 않는다. 아주 오래된 기사를 찾을 때는 검색어를 좁히는 것이 낫다.
+- `start + display - 1` 이 1000 을 넘는 조합(예: `start=1000&display=100`)은 proxy가 업스트림 호출 전에 `400 bad_request`(`"start + display exceeds Naver's 1000-item search window"`) 로 거절한다. 네이버 API 는 1000번째 아이템까지만 열람 가능하므로, 더 오래된 기사를 찾을 때는 검색어를 좁히는 것이 낫다.
+- 뉴스 `link` 중복 제거는 쿼리 파라미터 순서와 trailing slash 를 무시한 **canonical URL** 기준으로 수행된다(`?a=1&b=2` 와 `?b=2&a=1` 은 같은 기사로 간주). 실제 페이로드의 `link` 필드는 네이버가 돌려준 원문 그대로 노출한다.
 - `pub_date` 는 RFC822 형식, `pub_date_iso` 는 UTC ISO-8601 이다. 사용자에게 보여줄 때는 KST(UTC+9) 로 변환한다.
 - proxy route 는 public/read-only/no-auth 이며 5분 캐시 + 분당 60 회 rate limit 으로 남용을 막는다.
 - 기사 원문 풀텍스트가 필요하면 이 스킬로는 얻을 수 없다. 사용자가 링크를 직접 방문하도록 안내한다.
--- a/naver-news-search/SKILL.md
+++ b/naver-news-search/SKILL.md
@ -58,7 +58,7 @@ curl -fsS --get "${KSKILL_PROXY_BASE_URL:-https://k-skill-proxy.nomadamas.org}/v

 - `q` 또는 `query` — 검색어. 2글자 이상.
 - `display` — 반환 건수. 기본 10, 범위 1~100.
- `start` — 검색 시작 위치(1-indexed). 기본 1, 최대 1000. `start + display` 는 네이버 API 상 최대 1000 까지만 접근 가능하다.
+- `start` — 검색 시작 위치(1-indexed). 기본 1, 최대 1000. **`start + display - 1` 은 1000 을 넘을 수 없다**: 예를 들어 `start=1000 & display=100` 은 `1099`번째 아이템을 요구하므로 proxy가 업스트림 호출 전에 `400 bad_request`("start + display exceeds Naver's 1000-item search window")로 거절한다. 아주 오래된 기사를 찾으려면 검색어를 좁히는 것이 낫다.
 - `sort` — `sim`(유사도 순, 기본값) 또는 `date`(최신순). 그 외 값은 `sim` 으로 fallback.

 응답 주요 필드:
@ -91,7 +91,7 @@ curl -fsS --get "${KSKILL_PROXY_BASE_URL:-https://k-skill-proxy.nomadamas.org}/v

 ## Failure modes

- `400 bad_request` — 검색어 누락, 2글자 미만, 허용되지 않는 파라미터. 에러 메시지를 그대로 사용자에게 노출한다.
+- `400 bad_request` — 검색어 누락, 2글자 미만, 허용되지 않는 파라미터, 혹은 `start + display - 1 > 1000` 조합(네이버 1000-item search window 초과). 에러 메시지를 그대로 사용자에게 노출한다.
 - `503 upstream_not_configured` — 프록시 서버에 `NAVER_SEARCH_CLIENT_ID`/`NAVER_SEARCH_CLIENT_SECRET` 가 없는 경우. 운영자가 키를 등록해야 한다. 사용자에게는 "잠시 후 다시 시도해 주세요" 정도로 안내한다.
 - `401 upstream_error` — 프록시 서버의 Client ID/Secret 이 잘못된 경우(`errorCode: 024`). 운영자가 재발급해야 한다.
 - `429 upstream_error` — 네이버 검색 API 일일 쿼터(25,000 호출/일) 초과(`errorCode: 010`). 재시도 루프는 금지. 잠시 후 다시 시도하도록 안내한다.
--- a/packages/k-skill-proxy/README.md
+++ b/packages/k-skill-proxy/README.md
@ -28,6 +28,16 @@
 - `GET /v1/lh-notice/search` — LH 청약 공고 목록(`DATA_GO_KR_API_KEY`)
 - `GET /v1/lh-notice/detail` — LH 청약 공고 상세(`DATA_GO_KR_API_KEY`)

+## `/health` 업스트림 플래그 의미
+
+`/health` 의 `upstreams` 는 각 라우트의 **운영 가능 여부**를 보고하며, 같은 환경변수를 공유하는 라우트라도 **폴백 유무에 따라 의미가 달라진다**:
+
+- `naverShoppingConfigured` — 네이버 쇼핑 라우트는 공개 BFF JSON fallback 이 있어서 **항상 `true`** 다. 키가 없어도 public BFF 경로로 응답이 나간다.
+- `naverSearchApiConfigured` — 네이버 검색 Open API 키(`NAVER_SEARCH_CLIENT_ID` + `NAVER_SEARCH_CLIENT_SECRET`) 설정 여부. 네이버 쇼핑 라우트는 이 값이 `true` 면 공식 API 를 선호하고, `false` 면 BFF fallback 으로 자동 전환한다. 즉 이 플래그는 **쇼핑 쪽에서는 advisory** 다.
+- `naverNewsApiConfigured` — 네이버 뉴스 라우트의 **운영 가능 여부**. 뉴스에는 fallback 이 없어서 키가 없으면 뉴스 라우트는 `503 upstream_not_configured` 를 돌려준다.
+
+`naverSearchApiConfigured` 와 `naverNewsApiConfigured` 는 같은 환경변수에 의존하므로 현재 boolean 값은 항상 일치하지만, **의미(semantic contract)는 다르다**: 전자는 "공식 키가 있는지" 를, 후자는 "뉴스 라우트가 실제로 응답을 돌려줄 수 있는지" 를 보고한다. 향후 검색 키가 분리되거나 fallback 정책이 바뀌어도 이 두 플래그는 분리된 채 유지된다.
+
 ## 환경변수

 - `AIR_KOREA_OPEN_API_KEY` — 프록시 서버 쪽 AirKorea upstream key
--- a/packages/k-skill-proxy/src/naver-news.js
+++ b/packages/k-skill-proxy/src/naver-news.js
@ -5,6 +5,7 @@ const MAX_DISPLAY = 100;
 const DEFAULT_START = 1;
 const MIN_START = 1;
 const MAX_START = 1000;
+const MAX_SEARCH_WINDOW = 1000;
 const ALLOWED_SORTS = new Set(["sim", "date"]);

 function parseInteger(value, fallback) {
@ -64,6 +65,22 @@ function normalizeUrl(value) {
  return null;
 }

+function canonicalizeLinkForDedup(link) {
+  try {
+    const u = new URL(link);
+    const params = [...u.searchParams.entries()];
+    params.sort(([a], [b]) => (a < b ? -1 : a > b ? 1 : 0));
+    u.search = params.length ? new URLSearchParams(params).toString() : "";
+    if (u.pathname.length > 1 && u.pathname.endsWith("/")) {
+      u.pathname = u.pathname.replace(/\/+$/, "") || "/";
+    }
+    u.hash = "";
+    return u.toString().toLowerCase();
+  } catch {
+    return String(link).toLowerCase();
+  }
+}
+
 function parsePubDateIso(rfc822) {
  if (!rfc822) {
    return null;
@ -89,10 +106,21 @@ function normalizeNaverNewsSearchQuery(query) {
  const requestedSort = trimOrNull(query.sort) || "sim";
  const sort = ALLOWED_SORTS.has(requestedSort) ? requestedSort : "sim";

+  const display = clamp(rawDisplay, MIN_DISPLAY, MAX_DISPLAY);
+  const start = clamp(rawStart, MIN_START, MAX_START);
+
+  if (start + display - 1 > MAX_SEARCH_WINDOW) {
+    throw new Error(
+      `start + display exceeds Naver's ${MAX_SEARCH_WINDOW}-item search window ` +
+        `(start=${start} + display=${display} would fetch item ${start + display - 1}, ` +
+        `max accessible item is ${MAX_SEARCH_WINDOW}). Narrow the search or reduce start/display.`
+    );
+  }
+
  return {
    query: q,
-    display: clamp(rawDisplay, MIN_DISPLAY, MAX_DISPLAY),
-    start: clamp(rawStart, MIN_START, MAX_START),
+    display,
+    start,
    sort
  };
 }
@ -127,7 +155,7 @@ function normalizeNaverNewsSearchPayload(
    const pubDate = trimOrNull(item.pubDate);
    const pubDateIso = parsePubDateIso(pubDate);

-    const dedupKey = link.toLowerCase();
+    const dedupKey = canonicalizeLinkForDedup(link);
    if (seenLinks.has(dedupKey)) {
      continue;
    }
--- a/packages/k-skill-proxy/src/server.js
+++ b/packages/k-skill-proxy/src/server.js
@ -1276,32 +1276,35 @@ function buildServer({ env = process.env, provider = null, now = () => new Date(
    }
  });

-  app.get("/health", async () => ({
-    ok: true,
-    service: config.proxyName,
-    port: config.port,
-    upstreams: {
-      airKoreaConfigured: Boolean(config.airKoreaApiKey),
-      kmaOpenApiConfigured: Boolean(config.kmaOpenApiKey),
-      blueRibbonConfigured: Boolean(config.blueRibbonSessionId),
-      seoulOpenApiConfigured: Boolean(config.seoulOpenApiKey),
-      hrfcoConfigured: Boolean(config.hrfcoApiKey),
-      opinetConfigured: Boolean(config.opinetApiKey),
-      molitConfigured: Boolean(config.molitApiKey),
-      lhNoticeConfigured: Boolean(config.molitApiKey),
-      data4libraryConfigured: Boolean(config.data4libraryAuthKey),
-      foodsafetyKoreaConfigured: Boolean(config.foodsafetyKoreaApiKey),
-      neisSchoolMealConfigured: Boolean(config.keduInfoKey),
-      krxConfigured: Boolean(config.krxApiKey),
-      naverShoppingConfigured: true,
-      naverSearchApiConfigured: Boolean(config.naverSearchClientId && config.naverSearchClientSecret),
-      naverNewsApiConfigured: Boolean(config.naverSearchClientId && config.naverSearchClientSecret)
-    },
-    auth: {
-      tokenRequired: false
-    },
-    timestamp: new Date().toISOString()
-  }));
+  app.get("/health", async () => {
+    const naverSearchKeysPresent = Boolean(config.naverSearchClientId && config.naverSearchClientSecret);
+    return {
+      ok: true,
+      service: config.proxyName,
+      port: config.port,
+      upstreams: {
+        airKoreaConfigured: Boolean(config.airKoreaApiKey),
+        kmaOpenApiConfigured: Boolean(config.kmaOpenApiKey),
+        blueRibbonConfigured: Boolean(config.blueRibbonSessionId),
+        seoulOpenApiConfigured: Boolean(config.seoulOpenApiKey),
+        hrfcoConfigured: Boolean(config.hrfcoApiKey),
+        opinetConfigured: Boolean(config.opinetApiKey),
+        molitConfigured: Boolean(config.molitApiKey),
+        lhNoticeConfigured: Boolean(config.molitApiKey),
+        data4libraryConfigured: Boolean(config.data4libraryAuthKey),
+        foodsafetyKoreaConfigured: Boolean(config.foodsafetyKoreaApiKey),
+        neisSchoolMealConfigured: Boolean(config.keduInfoKey),
+        krxConfigured: Boolean(config.krxApiKey),
+        naverShoppingConfigured: true,
+        naverSearchApiConfigured: naverSearchKeysPresent,
+        naverNewsApiConfigured: naverSearchKeysPresent
+      },
+      auth: {
+        tokenRequired: false
+      },
+      timestamp: new Date().toISOString()
+    };
+  });

  app.get("/B552584/:service/:operation", async (request, reply) => {
    const { service, operation } = request.params;
--- a/packages/k-skill-proxy/test/naver-news.test.js
+++ b/packages/k-skill-proxy/test/naver-news.test.js
@ -15,10 +15,20 @@ test("normalizeNaverNewsSearchQuery validates q/query and clamps display/start/s
  assert.throws(() => normalizeNaverNewsSearchQuery({ q: "a" }), /at least 2/);

  assert.deepEqual(
-    normalizeNaverNewsSearchQuery({ query: "  인공지능  ", display: "999", start: "9999", sort: "date" }),
+    normalizeNaverNewsSearchQuery({ query: "  인공지능  ", display: "999", start: "1", sort: "date" }),
    {
      query: "인공지능",
      display: 100,
+      start: 1,
+      sort: "date"
+    }
+  );
+
+  assert.deepEqual(
+    normalizeNaverNewsSearchQuery({ query: "주식", display: "1", start: "9999", sort: "date" }),
+    {
+      query: "주식",
+      display: 1,
      start: 1000,
      sort: "date"
    }
@ -55,16 +65,60 @@ test("normalizeNaverNewsSearchQuery validates q/query and clamps display/start/s
  );
 });

-test("normalizeNaverNewsSearchQuery aliases keyword and caps start+display at 1000 window", () => {
+test("normalizeNaverNewsSearchQuery accepts keyword as an alias for q/query", () => {
  assert.deepEqual(
-    normalizeNaverNewsSearchQuery({ keyword: "스타트업", display: "50", start: "1000" }),
+    normalizeNaverNewsSearchQuery({ keyword: "스타트업" }),
    {
      query: "스타트업",
-      display: 50,
-      start: 1000,
+      display: 10,
+      start: 1,
      sort: "sim"
    }
  );
+
+  assert.deepEqual(
+    normalizeNaverNewsSearchQuery({ keyword: "반도체", display: "20", start: "5", sort: "date" }),
+    {
+      query: "반도체",
+      display: 20,
+      start: 5,
+      sort: "date"
+    }
+  );
+});
+
+test("normalizeNaverNewsSearchQuery rejects start+display combinations exceeding Naver's 1000-item window", () => {
+  // Boundary values that are still valid (start + display - 1 === 1000 or below) must pass.
+  assert.deepEqual(
+    normalizeNaverNewsSearchQuery({ q: "경계", start: "1000", display: "1" }),
+    { query: "경계", display: 1, start: 1000, sort: "sim" }
+  );
+  assert.deepEqual(
+    normalizeNaverNewsSearchQuery({ q: "경계", start: "901", display: "100" }),
+    { query: "경계", display: 100, start: 901, sort: "sim" }
+  );
+  assert.deepEqual(
+    normalizeNaverNewsSearchQuery({ q: "경계", start: "500", display: "100" }),
+    { query: "경계", display: 100, start: 500, sort: "sim" }
+  );
+
+  // One past the boundary (start + display - 1 > 1000) must throw preflight 400.
+  assert.throws(
+    () => normalizeNaverNewsSearchQuery({ q: "초과", start: "902", display: "100" }),
+    /1000-item|window|Naver/i
+  );
+  assert.throws(
+    () => normalizeNaverNewsSearchQuery({ q: "초과", start: "1000", display: "2" }),
+    /1000-item|window|Naver/i
+  );
+  assert.throws(
+    () => normalizeNaverNewsSearchQuery({ q: "초과", start: "1000", display: "100" }),
+    /1000-item|window|Naver/i
+  );
+  assert.throws(
+    () => normalizeNaverNewsSearchQuery({ q: "초과", start: "950", display: "60" }),
+    /1000-item|window|Naver/i
+  );
 });

 test("buildNaverNewsSearchUrl constructs the official Naver Search news endpoint URL", () => {
@ -186,6 +240,99 @@ test("normalizeNaverNewsSearchPayload skips items without title or link and dedu
  assert.equal(result.items[0].title, "정상 기사");
 });

+test("normalizeNaverNewsSearchPayload dedupes links that differ only in query-param order, trailing slash, or host casing", () => {
+  const result = normalizeNaverNewsSearchPayload(
+    {
+      lastBuildDate: "Mon, 22 Apr 2026 00:00:00 +0900",
+      total: 5,
+      start: 1,
+      display: 5,
+      items: [
+        {
+          title: "원본 기사",
+          originallink: "https://publisher.example.com/42",
+          link: "https://news.example.com/articles/42?a=1&b=2",
+          description: "본문",
+          pubDate: "Mon, 22 Apr 2026 00:00:00 +0900"
+        },
+        {
+          title: "쿼리 파라미터 순서만 다른 중복",
+          originallink: "https://publisher.example.com/42-b",
+          link: "https://news.example.com/articles/42?b=2&a=1",
+          description: "본문",
+          pubDate: "Mon, 22 Apr 2026 00:00:00 +0900"
+        },
+        {
+          title: "trailing slash 만 다른 중복",
+          originallink: "https://publisher.example.com/42-c",
+          link: "https://news.example.com/articles/42/?a=1&b=2",
+          description: "본문",
+          pubDate: "Mon, 22 Apr 2026 00:00:00 +0900"
+        },
+        {
+          title: "host 대소문자·fragment 만 다른 중복",
+          originallink: "https://publisher.example.com/42-d",
+          link: "https://NEWS.example.com/articles/42?a=1&b=2#comments",
+          description: "본문",
+          pubDate: "Mon, 22 Apr 2026 00:00:00 +0900"
+        },
+        {
+          title: "진짜 다른 기사",
+          originallink: "https://publisher.example.com/43",
+          link: "https://news.example.com/articles/43?a=1&b=2",
+          description: "본문",
+          pubDate: "Mon, 22 Apr 2026 00:00:00 +0900"
+        }
+      ]
+    },
+    { query: "중복", display: 10, start: 1, sort: "sim" }
+  );
+
+  assert.equal(result.items.length, 2);
+  assert.equal(result.items[0].title, "원본 기사");
+  assert.equal(result.items[1].title, "진짜 다른 기사");
+});
+
+test("normalizeNaverNewsSearchPayload preserves items that differ by path or by a non-redundant query param", () => {
+  const result = normalizeNaverNewsSearchPayload(
+    {
+      lastBuildDate: "Mon, 22 Apr 2026 00:00:00 +0900",
+      total: 3,
+      start: 1,
+      display: 3,
+      items: [
+        {
+          title: "첫 번째",
+          originallink: "https://publisher.example.com/1",
+          link: "https://news.example.com/articles/42?a=1",
+          description: "본문",
+          pubDate: "Mon, 22 Apr 2026 00:00:00 +0900"
+        },
+        {
+          title: "다른 쿼리 값",
+          originallink: "https://publisher.example.com/2",
+          link: "https://news.example.com/articles/42?a=2",
+          description: "본문",
+          pubDate: "Mon, 22 Apr 2026 00:00:00 +0900"
+        },
+        {
+          title: "다른 경로",
+          originallink: "https://publisher.example.com/3",
+          link: "https://news.example.com/articles/42/related?a=1",
+          description: "본문",
+          pubDate: "Mon, 22 Apr 2026 00:00:00 +0900"
+        }
+      ]
+    },
+    { query: "서로다른", display: 10, start: 1, sort: "sim" }
+  );
+
+  assert.equal(result.items.length, 3);
+  assert.equal(result.items[0].title, "첫 번째");
+  assert.equal(result.items[1].title, "다른 쿼리 값");
+  assert.equal(result.items[2].title, "다른 경로");
+});
+
 test("normalizeNaverNewsSearchPayload handles missing optional fields gracefully", () => {
  const result = normalizeNaverNewsSearchPayload(
    {
@ -248,6 +395,38 @@ test("naver news search endpoint returns 503 when proxy credentials are missing"
  assert.match(body.message, /NAVER_SEARCH_CLIENT_ID/);
 });

+test("naver news search endpoint returns 400 preflight when start+display exceeds Naver's 1000-item window", async (t) => {
+  const originalFetch = global.fetch;
+  let fetchCount = 0;
+  global.fetch = async () => {
+    fetchCount += 1;
+    return new Response("{}", { status: 200, headers: { "content-type": "application/json" } });
+  };
+
+  const app = buildServer({
+    env: {
+      NAVER_SEARCH_CLIENT_ID: "client-id",
+      NAVER_SEARCH_CLIENT_SECRET: "client-secret",
+      KSKILL_PROXY_CACHE_TTL_MS: "60000"
+    }
+  });
+
+  t.after(async () => {
+    global.fetch = originalFetch;
+    await app.close();
+  });
+
+  const response = await app.inject({
+    method: "GET",
+    url: "/v1/naver-news/search?q=%EC%82%BC%EC%84%B1%EC%A0%84%EC%9E%90&start=1000&display=100"
+  });
+  assert.equal(response.statusCode, 400);
+  const body = response.json();
+  assert.equal(body.error, "bad_request");
+  assert.match(body.message, /1000-item|window|Naver/i);
+  assert.equal(fetchCount, 0, "must not call upstream when preflight fails");
+});
+
 test("naver news search endpoint proxies to official API with correct headers and params", async (t) => {
  const originalFetch = global.fetch;
  const fetchCalls = [];