diff --git a/SVSim.UnitTests/Controllers/AdminControllerTests.cs b/SVSim.UnitTests/Controllers/AdminControllerTests.cs
index 87f6b84..37796b8 100644
--- a/SVSim.UnitTests/Controllers/AdminControllerTests.cs
+++ b/SVSim.UnitTests/Controllers/AdminControllerTests.cs
@@ -342,4 +342,62 @@ public class AdminControllerTests
         Assert.That(stored.Decks, Is.Empty,
             "Default-deck cloning was removed; a fresh viewer with no imported decks has none.");
     }
+
+    [Test]
+    public async Task ImportViewer_binds_new_fields_from_literal_client_json()
+    {
+        using var factory = new SVSimTestFactory();
+        const ulong steamId = 76_561_198_111_222_340UL;
+        long viewerId = await factory.SeedViewerAsync(steamId: steamId);
+        await factory.SeedOwnedItemAsync(viewerId, itemId: 70001, count: 0); // register item master
+
+        int classId, leaderSkinId; long sleeveId;
+        using (var scope = factory.Services.CreateScope())
+        {
+            var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+            classId = (await db.Classes.FirstAsync()).Id;
+            sleeveId = (await db.Sleeves.FirstAsync()).Id;
+            leaderSkinId = (await db.LeaderSkins.FirstAsync()).Id;
+        }
+
+        string json = $$"""
+        {
+          "steam_id": {{steamId}},
+          "owned_cards": [ { "card_id": 10001001, "count": 2, "is_protected": true } ],
+          "items": [ { "item_id": 70001, "count": 4 } ],
+          "decks": [ {
+            "deck_format": 1,
+            "deck_no": 2,
+            "deck_name": "Wire Deck",
+            "class_id": {{classId}},
+            "sleeve_id": {{sleeveId}},
+            "leader_skin_id": {{leaderSkinId}},
+            "is_random_leader_skin": 0,
+            "card_id_array": [10001001, 10001002]
+          } ]
+        }
+        """;
+
+        using var client = factory.CreateClient();
+        using var content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");
+        var response = await client.PostAsync("/admin/import_viewer", content);
+
+        Assert.That(response.StatusCode, Is.EqualTo(HttpStatusCode.OK),
+            await response.Content.ReadAsStringAsync());
+
+        using var scope2 = factory.Services.CreateScope();
+        var db2 = scope2.ServiceProvider.GetRequiredService<SVSimDbContext>();
+        var stored = await db2.Viewers
+            .Include(v => v.Cards).ThenInclude(c => c.Card)
+            .Include(v => v.Items).ThenInclude(i => i.Item)
+            .Include(v => v.Decks)
+            .FirstAsync(v => v.Id == viewerId);
+
+        Assert.That(stored.Cards.Any(c => c.Card.Id == 10001001L && c.Count == 2 && c.IsProtected), Is.True,
+            "owned_cards snake_case keys must bind (card_id/count/is_protected).");
+        Assert.That(stored.Items.Any(i => i.Item.Id == 70001 && i.Count == 4), Is.True,
+            "items snake_case keys must bind (item_id/count).");
+        Assert.That(stored.Decks.Any(d => d.Name == "Wire Deck" && d.Format == Format.Rotation), Is.True,
+            "decks snake_case keys must bind (deck_format/deck_no/class_id/card_id_array/...).");
+    }
 }