diff --git a/SVSim.UnitTests/Wire/ItemAcquireHistoryWireShape.cs b/SVSim.UnitTests/Wire/ItemAcquireHistoryWireShape.cs
new file mode 100644
index 0000000..ce60370
--- /dev/null
+++ b/SVSim.UnitTests/Wire/ItemAcquireHistoryWireShape.cs
@@ -0,0 +1,46 @@
+using System.Text.Json;
+using SVSim.EmulatedEntrypoint.Models.Dtos.ItemAcquireHistory;
+
+namespace SVSim.UnitTests.Wire;
+
+public class ItemAcquireHistoryWireShape
+{
+    [Test]
+    public void Response_serialization_matches_prod_capture_keys()
+    {
+        var response = new ItemAcquireHistoryInfoResponse
+        {
+            Histories =
+            {
+                new ItemAcquireHistoryEntryDto
+                {
+                    RewardType = "9",
+                    RewardDetailId = "0",
+                    RewardCount = "20",
+                    AcquireType = "1",
+                    AcquireTime = "2026-06-09 16:59:44",
+                    Message = "Daily Bonus: Day 2",
+                },
+            },
+        };
+
+        var options = new JsonSerializerOptions
+        {
+            PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,
+            DefaultIgnoreCondition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingNull,
+        };
+        var json = JsonSerializer.Serialize(response, options);
+
+        // Prod capture line ~93 (formatted for diff legibility):
+        var expected = "{\"histories\":[{" +
+            "\"reward_type\":\"9\"," +
+            "\"reward_detail_id\":\"0\"," +
+            "\"reward_count\":\"20\"," +
+            "\"acquire_type\":\"1\"," +
+            "\"acquire_time\":\"2026-06-09 16:59:44\"," +
+            "\"message\":\"Daily Bonus: Day 2\"" +
+            "}]}";
+
+        Assert.That(json, Is.EqualTo(expected));
+    }
+}