diff --git a/src/AcDream.App/UI/Layout/ExternalContainerController.cs b/src/AcDream.App/UI/Layout/ExternalContainerController.cs
index d7bf4460..db66e5ed 100644
--- a/src/AcDream.App/UI/Layout/ExternalContainerController.cs
+++ b/src/AcDream.App/UI/Layout/ExternalContainerController.cs
@@ -363,6 +363,7 @@ public sealed class ExternalContainerController : IItemListDragHandler, IRetaine
             SpriteResolve = owner.SpriteResolve,
             SlotIndex = owner.GetNumUIItems(),
             SourceKind = source,
+            TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
         };
         cell.SetItem(guid, icon, dragIconTexture: dragIcon);
         return cell;
diff --git a/src/AcDream.App/UI/Layout/InventoryController.cs b/src/AcDream.App/UI/Layout/InventoryController.cs
index f39b8e83..320a6eec 100644
--- a/src/AcDream.App/UI/Layout/InventoryController.cs
+++ b/src/AcDream.App/UI/Layout/InventoryController.cs
@@ -444,7 +444,11 @@ public sealed class InventoryController : IItemListDragHandler, IRetainedPanelCo
         {
             const uint PlayerPackBaseIcon = 0x0600127Eu;   // constant main-pack backpack (visual gate)
             _topContainer.Flush();
-            var main = new UiItemSlot { SpriteResolve = _topContainer.SpriteResolve };
+            var main = new UiItemSlot
+            {
+                SpriteResolve = _topContainer.SpriteResolve,
+                TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
+            };
             main.SetItem(
                 p,
                 _iconIds(ItemType.Container, PlayerPackBaseIcon, 0u, 0u, 0u),
@@ -486,7 +490,11 @@ public sealed class InventoryController : IItemListDragHandler, IRetainedPanelCo
         uint dragTex = item is null ? 0u
             : _dragIconIds?.Invoke(
                 item.Type, item.IconId, item.IconUnderlayId, item.IconOverlayId, item.Effects) ?? 0u;
-        var cell = new UiItemSlot { SpriteResolve = list.SpriteResolve };
+        var cell = new UiItemSlot
+        {
+            SpriteResolve = list.SpriteResolve,
+            TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
+        };
         cell.SetItem(guid, tex, dragIconTexture: dragTex);
         cell.SetWaitingState(waiting);
         cell.SlotIndex = list.GetNumUIItems();                 // index it will occupy (== its slot in a packed list)
diff --git a/src/AcDream.App/UI/Layout/PaperdollController.cs b/src/AcDream.App/UI/Layout/PaperdollController.cs
index 9d84f10b..4d925ed9 100644
--- a/src/AcDream.App/UI/Layout/PaperdollController.cs
+++ b/src/AcDream.App/UI/Layout/PaperdollController.cs
@@ -88,6 +88,7 @@ public sealed class PaperdollController : IItemListDragHandler, IRetainedPanelCo
             list.ExamineItemRequested = ExamineItem;
             list.Cell.SourceKind  = ItemDragSource.Equipment;
             list.Cell.SlotIndex   = i;              // definition position = equipped drag-payload SourceSlot
+            list.Cell.TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName();
             list.Cell.EmptySprite = emptySlotSprites is not null
                 && emptySlotSprites.TryGetValue(element, out uint authoredSprite)
                     ? authoredSprite
diff --git a/src/AcDream.App/UI/Layout/SecureTradeUiController.cs b/src/AcDream.App/UI/Layout/SecureTradeUiController.cs
index b03fc02b..091a5574 100644
--- a/src/AcDream.App/UI/Layout/SecureTradeUiController.cs
+++ b/src/AcDream.App/UI/Layout/SecureTradeUiController.cs
@@ -295,6 +295,7 @@ public sealed class SecureTradeUiController : IRetainedPanelController
                     // Your staged items carry retail's trading marker.
                     ShowTradeOverlay = side == RuntimeTradeSide.Self,
                     TradeOverlaySprite = TradeOverlaySpriteId,
+                    TooltipTextResolve = g => _bindings.Objects.Get(g)?.GetTooltipDisplayName(),
                 };
                 cell.SetItem(guid, icon);
                 list.AddItem(cell);
diff --git a/src/AcDream.App/UI/Layout/ToolbarController.cs b/src/AcDream.App/UI/Layout/ToolbarController.cs
index 9d880d84..e0b0c010 100644
--- a/src/AcDream.App/UI/Layout/ToolbarController.cs
+++ b/src/AcDream.App/UI/Layout/ToolbarController.cs
@@ -145,6 +145,7 @@ public sealed class ToolbarController : IItemListDragHandler, IRetainedPanelCont
                 list.Cell.SlotIndex  = i;
                 list.Cell.SourceKind = ItemDragSource.ShortcutBar;
                 list.Cell.DragAcceptSprite = 0x060011FAu;   // green cross (toolbar), not the ring 0x060011F9 (inventory)
+                list.Cell.TooltipTextResolve = g => _repo.Get(g)?.GetTooltipDisplayName();
             }
         }
 
diff --git a/src/AcDream.App/UI/Layout/VendorUiController.cs b/src/AcDream.App/UI/Layout/VendorUiController.cs
index b1edcc8b..b1ddf49e 100644
--- a/src/AcDream.App/UI/Layout/VendorUiController.cs
+++ b/src/AcDream.App/UI/Layout/VendorUiController.cs
@@ -1102,6 +1102,10 @@ public sealed class VendorUiController : IRetainedPanelController, IItemListDrag
                         // comment for why this must be gated at the source,
                         // not left to every destination handler to reject.
                         AllowDragSource = false,
+                        // Shop items are materialized into ClientObjectTable
+                        // (VendorShopItemMaterializer), so the same resolver
+                        // every other physical cell uses works here too.
+                        TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
                     };
                     cell.SetItem(item.ItemGuid, icon);
                     cell.Selected = item.ItemGuid == selectedGuid;
@@ -2205,6 +2209,7 @@ public sealed class VendorUiController : IRetainedPanelController, IItemListDrag
                     SpriteResolve = list.SpriteResolve,
                     SlotIndex = list.GetNumUIItems(),
                     AllowDragSource = false,
+                    TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
                 };
                 cell.SetItem(shopItem.ItemGuid, icon);
                 cell.Selected = shopItem.ItemGuid == selectedGuid;
@@ -2243,6 +2248,7 @@ public sealed class VendorUiController : IRetainedPanelController, IItemListDrag
                     SpriteResolve = list.SpriteResolve,
                     SlotIndex = list.GetNumUIItems(),
                     AllowDragSource = false,
+                    TooltipTextResolve = g => _objects.Get(g)?.GetTooltipDisplayName(),
                 };
                 cell.SetItem(item.ObjectId, icon);
                 cell.Selected = item.ObjectId == selectedGuid;
diff --git a/src/AcDream.App/UI/UiItemSlot.cs b/src/AcDream.App/UI/UiItemSlot.cs
index 614ec3b6..8a06c830 100644
--- a/src/AcDream.App/UI/UiItemSlot.cs
+++ b/src/AcDream.App/UI/UiItemSlot.cs
@@ -12,13 +12,63 @@ namespace AcDream.App.UI;
 /// </summary>
 public class UiItemSlot : UiElement
 {
-    public UiItemSlot() { ClickThrough = false; }
+    /// <summary>
+    /// Retail's shared UIItem cell-template catalog (<c>ItemListCellTemplate.
+    /// CatalogLayoutId</c>, LayoutDesc <c>0x21000037</c>) authors the SAME
+    /// tooltip popup locator on every one of its 49 standalone prototypes —
+    /// live-DAT-probed 2026-08-16: every top-level catalog child (inventory's
+    /// 32x32 cell <c>0x1000033A</c>, the toolbar's per-slot prototypes
+    /// <c>0x1000043B</c>.., the container cell <c>0x1000033F</c>, and every
+    /// paperdoll/armor slot skin alike) resolves <c>P0x47=0x10000395</c> /
+    /// <c>P0x48=0x21000041</c> through catalog inheritance, matching one of
+    /// the four popup skins <see cref="Layout.RetailTooltipPresenter"/> already
+    /// mounts for every other tooltip-bearing element
+    /// (<c>Layout.TooltipLiveDatTests.PopupSkinRootIds</c>). Since
+    /// <see cref="UiItemSlot"/> cells are built programmatically (never through
+    /// <c>LayoutImporter.Build</c>), this port hardcodes the uniform pair here
+    /// rather than re-deriving it per instance — the same "exhaustive scan,
+    /// then hardcode" shape as <c>RetailCursorCatalog</c>'s five window-control
+    /// cursor DIDs and <c>ItemListCellTemplate.CatalogLayoutId</c> itself.
+    /// </summary>
+    private const uint ItemTooltipRootElementId = 0x10000395u;
+    private const uint ItemTooltipLayoutDid = 0x21000041u;
+
+    public UiItemSlot()
+    {
+        ClickThrough = false;
+        AuthoredTooltipRootElementId = ItemTooltipRootElementId;
+        AuthoredTooltipLayoutDid = ItemTooltipLayoutDid;
+    }
 
     public override bool ConsumesDatChildren => true;
 
     /// <summary>Bound weenie guid (0 = empty). Retail UIElement_UIItem::itemID.</summary>
     public uint ItemId { get; private set; }
 
+    /// <summary>
+    /// Resolves <see cref="ItemId"/> to its retail tooltip text (a
+    /// <see cref="AcDream.Core.Items.ClientObject.GetTooltipDisplayName"/>
+    /// call bound by the owning controller — every construction site already
+    /// has a <c>ClientObjectTable</c> reference in scope, matching how
+    /// <see cref="SpriteResolve"/> is wired). Null/empty result shows no
+    /// tooltip, matching retail's <c>UIItem_Update</c> early-out
+    /// (<c>weenObj == 0</c> -&gt; <c>UIElement::ClearTooltip</c>) for an
+    /// empty or not-yet-materialized cell.
+    /// </summary>
+    public Func<uint, string?>? TooltipTextResolve { get; set; }
+
+    /// <summary>
+    /// Port of <c>UIElement_UIItem::UpdateTooltip @0x004E1CB0</c>: called every
+    /// refresh (retail's own callers are heartbeat/state-change driven), but
+    /// computed lazily here — the same "runtime text on demand" shape already
+    /// established by <see cref="UiButton.GetTooltipText"/> and
+    /// <see cref="UiRadar.GetTooltipText"/> — rather than cached at
+    /// <see cref="SetItem"/> time, since nothing observes a stale value between
+    /// item-state changes and the next hover dwell.
+    /// </summary>
+    public override string? GetTooltipText()
+        => ItemId != 0 ? TooltipTextResolve?.Invoke(ItemId) : null;
+
     /// <summary>Pre-composited icon GL texture for the bound item (0 = none).</summary>
     public uint IconTexture { get; private set; }
 
diff --git a/src/AcDream.Core/Items/ClientObject.cs b/src/AcDream.Core/Items/ClientObject.cs
index 5f4611d0..42a99890 100644
--- a/src/AcDream.Core/Items/ClientObject.cs
+++ b/src/AcDream.Core/Items/ClientObject.cs
@@ -347,6 +347,22 @@ public sealed class ClientObject
         if (string.IsNullOrEmpty(Name)) return Name;
         return Name[^1] == 's' ? Name + "es" : Name + "s";
     }
+
+    /// <summary>
+    /// Ports <c>UIElement_UIItem::UpdateTooltip @0x004E1CB0</c> — the item-cell
+    /// hover-tooltip text every physical item/container/shortcut cell shows.
+    /// Retail resolves the name with <c>NAME_APPROPRIATE</c> (the same call
+    /// <see cref="GetAppropriateName"/> already ports) and, only when the stack
+    /// holds more than one (<c>_stackSize_1 &gt; 1 @0x004e1d12</c>), prefixes the
+    /// count via <c>PStringBase&lt;unsigned short&gt;::sprintf(&amp;__return,
+    /// u"%d %s")</c> — count first, one space, then the (already
+    /// singular-or-plural) name.
+    /// </summary>
+    public string GetTooltipDisplayName()
+    {
+        string name = GetAppropriateName();
+        return StackSize > 1 ? $"{StackSize} {name}" : name;
+    }
 }
 
 /// <summary>