diff --git a/forge-gui-desktop/src/test/java/forge/net/RevealSyncDeltaTest.java b/forge-gui-desktop/src/test/java/forge/net/RevealSyncDeltaTest.java
new file mode 100644
index 000000000000..6bd805470264
--- /dev/null
+++ b/forge-gui-desktop/src/test/java/forge/net/RevealSyncDeltaTest.java
@@ -0,0 +1,102 @@
+package forge.net;
+
+import forge.ai.AITest;
+import forge.game.Game;
+import forge.game.GameView;
+import forge.game.card.CardView;
+import forge.game.player.Player;
+import forge.game.player.PlayerView;
+import forge.game.zone.ZoneType;
+import forge.gamemodes.net.DeltaPacket;
+import forge.gamemodes.net.server.DeltaSyncManager;
+import forge.trackable.TrackableProperty;
+
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import java.util.Map;
+
+/**
+ * Reusable harness for verifying that host-side game-state changes actually reach a
+ * networked client through the real delta-sync path ({@link DeltaSyncManager}).
+ *
+ * <p>Pattern for tests of this type:
+ * <ol>
+ *   <li>Build an exact board with {@link AITest} helpers (deterministic — no AI, no sockets).</li>
+ *   <li>Take an initial full sync with a fresh {@link DeltaSyncManager} (client is "caught up").</li>
+ *   <li>Mutate the host state (the thing under test).</li>
+ *   <li>Collect the incremental delta and assert the change is present in it — i.e. the client
+ *       would receive it.</li>
+ * </ol>
+ *
+ * <p>The first scenario here is the "own top-library card reveal" sync: a Future Sight controller
+ * must be able to see the revealed top card of their own (hidden) library on their client. This runs
+ * the SAME delta code the iOS/desktop network clients use (default {@code useDeltaSync=true}), but
+ * deterministically and in-process.
+ *
+ * <p>Why a dedicated test: a delta regression that drops a hidden-zone reveal is otherwise
+ * invisible — the periodic network checksums did not walk the Library zone.
+ */
+public class RevealSyncDeltaTest extends AITest {
+
+    /** Find the delta entry (new-object or incremental) for a given trackable id, or null. */
+    private static Map<TrackableProperty, Object> deltaFor(DeltaPacket packet, int cardViewId) {
+        int key = DeltaPacket.makeDeltaKey(DeltaPacket.TYPE_CARD_VIEW, cardViewId);
+        Map<TrackableProperty, Object> d = packet.getObjectDeltas().get(key);
+        if (d == null) {
+            d = packet.getNewObjects().get(key);
+        }
+        return d;
+    }
+
+    @Test
+    public void topLibraryRevealReachesClientDelta() {
+        Game game = initAndCreateGame();
+        Player a = game.getPlayers().get(1); // active player; the "reveal owner"
+
+        // One card in A's (hidden) library — this is the top card Future Sight reveals.
+        addCardToZone("Island", a, ZoneType.Library);
+        game.getAction().checkStateEffects(true);
+
+        GameView gv = game.getView();
+        // Realize the library CardView so it exists in the view graph before the initial sync.
+        CardView topBefore = gv.getPlayers().get(1).getCards(ZoneType.Library).iterator().next();
+        PlayerView aView = gv.getPlayers().get(1);
+        int topId = topBefore.getId();
+
+        Assert.assertFalse(topBefore.canBeShownTo(aView),
+                "Precondition: with no reveal source, A must NOT see its own top library card");
+
+        // 1. Initial full sync — the client is now caught up (no reveal yet).
+        DeltaSyncManager sync = new DeltaSyncManager();
+        sync.collectDeltas(gv);
+
+        // 2. Host-side change under test: Future Sight enters A's battlefield and its continuous
+        //    static grants A may-look on the top library card.
+        addCard("Future Sight", a);
+        game.getAction().checkStateEffects(true);
+
+        // Host truth: A can now see its own top library card.
+        Assert.assertTrue(topBefore.canBeShownTo(aView),
+                "Host state: with Future Sight in play, A should see its own top library card");
+
+        // 3. Collect the incremental delta the client would receive.
+        sync.registerNewObjects(gv);
+        DeltaPacket delta = sync.collectDeltas(gv);
+
+        // 4. The decisive check: does the reveal (PlayerMayLook on the top library CardView)
+        //    actually travel in the delta? If yes, the client syncs the reveal.
+        Map<TrackableProperty, Object> cardDelta = deltaFor(delta, topId);
+        boolean mayLookInDelta = cardDelta != null && cardDelta.containsKey(TrackableProperty.PlayerMayLook);
+
+        System.out.println("[REVEALSYNC] top library CardView id=" + topId
+                + " present-in-delta=" + (cardDelta != null)
+                + " PlayerMayLook-in-delta=" + mayLookInDelta
+                + (cardDelta != null ? " props=" + cardDelta.keySet() : ""));
+
+        Assert.assertTrue(mayLookInDelta,
+                "The top library card's PlayerMayLook reveal must be present in the client delta, "
+                        + "otherwise the owning player never sees their own revealed top card. "
+                        + "cardDelta=" + cardDelta);
+    }
+}
diff --git a/forge-gui/src/main/java/forge/gamemodes/net/NetworkChecksumUtil.java b/forge-gui/src/main/java/forge/gamemodes/net/NetworkChecksumUtil.java
index 95aeaa36f1ec..d5df029c0d28 100644
--- a/forge-gui/src/main/java/forge/gamemodes/net/NetworkChecksumUtil.java
+++ b/forge-gui/src/main/java/forge/gamemodes/net/NetworkChecksumUtil.java
@@ -382,6 +382,7 @@ public static List<TrackableObject> collectChecksumObjects(GameView gameView) {
             addCards(cards, getEffectiveValue(player, TrackableProperty.Graveyard));
             addCards(cards, getEffectiveValue(player, TrackableProperty.Exile));
             addCards(cards, getEffectiveValue(player, TrackableProperty.Command));
+            addCards(cards, getEffectiveValue(player, TrackableProperty.Library));
             cards.sort(Comparator.comparingInt(CardView::getId));
 
             for (CardView card : cards) {