diff --git a/artifacts/api-server/tests/executive-meetings.test.mjs b/artifacts/api-server/tests/executive-meetings.test.mjs
index fc153bf8..54819262 100644
--- a/artifacts/api-server/tests/executive-meetings.test.mjs
+++ b/artifacts/api-server/tests/executive-meetings.test.mjs
@@ -663,6 +663,28 @@ test("Reorder: POST /reorder renumbers a full day to 1..N and inherits slot time
     "audit new_value.order must echo the new ordering");
 });
 
+test("Reorder: rejects orderedIds containing duplicates with code duplicate_ids", async () => {
+  // Even though full-day membership would otherwise be satisfied, sending the
+  // same id twice must be refused so we never assign the same dailyNumber to
+  // two distinct rows during the two-phase renumber.
+  const reorderDate = "2050-04-04";
+  const a = await api(adminCookie, "POST", "/api/executive-meetings", {
+    titleAr: "أ", titleEn: "A", meetingDate: reorderDate,
+  });
+  const A = await a.json(); created.meetingIds.push(A.id);
+  const b = await api(adminCookie, "POST", "/api/executive-meetings", {
+    titleAr: "ب", titleEn: "B", meetingDate: reorderDate,
+  });
+  const B = await b.json(); created.meetingIds.push(B.id);
+  const r = await api(adminCookie, "POST",
+    "/api/executive-meetings/reorder",
+    { meetingDate: reorderDate, orderedIds: [A.id, A.id, B.id] });
+  assert.equal(r.status, 400);
+  const body = await r.json();
+  assert.equal(body.code, "duplicate_ids",
+    "duplicate ids must be reported with the duplicate_ids code");
+});
+
 test("Reorder: rejects an incomplete-day request (orderedIds missing some)", async () => {
   const reorderDate = "2050-02-20";
   const a = await api(adminCookie, "POST", "/api/executive-meetings", {