diff --git a/docs/superpowers/plans/2026-06-18-d54-object-item-model.md b/docs/superpowers/plans/2026-06-18-d54-object-item-model.md
index 9bfcee13..080f8988 100644
--- a/docs/superpowers/plans/2026-06-18-d54-object-item-model.md
+++ b/docs/superpowers/plans/2026-06-18-d54-object-item-model.md
@@ -201,9 +201,9 @@ public void TryParse_FullItemFields_Captured()
     var parsed = CreateObject.TryParse(body);
     Assert.NotNull(parsed);
     var p = parsed!.Value;
-    Assert.Equal(250u, p.Value);
+    Assert.Equal(250, p.Value);
     Assert.Equal(7, p.StackSize);
-    Assert.Equal(100u, p.StackSizeMax);
+    Assert.Equal(100, p.StackSizeMax);
     Assert.Equal(42, p.Burden);
     Assert.Equal(24, p.ItemsCapacity);
     Assert.Equal(7, p.ContainersCapacity);
@@ -255,7 +255,7 @@ In `CreateObject.cs`, append these parameters to the `Parsed` record (after `UiE
         uint WeenieClassId = 0,
         int? Value = null,
         int? StackSize = null,
-        uint? StackSizeMax = null,
+        int? StackSizeMax = null,
         int? Burden = null,
         int? ItemsCapacity = null,
         int? ContainersCapacity = null,
@@ -415,7 +415,7 @@ Append to the `EntitySpawn` record (after `uint UiEffects = 0`, change it to `,`
         uint WeenieClassId = 0,
         int? Value = null,
         int? StackSize = null,
-        uint? StackSizeMax = null,
+        int? StackSizeMax = null,
         int? Burden = null,
         int? ItemsCapacity = null,
         int? ContainersCapacity = null,
@@ -557,7 +557,7 @@ public readonly record struct WeenieData(
     uint Effects,
     int? Value,
     int? StackSize,
-    uint? StackSizeMax,
+    int? StackSizeMax,
     int? Burden,
     uint? ContainerId,
     uint? WielderId,
@@ -714,7 +714,7 @@ In `ClientObjectTable.cs`, rename the backing field `_items` → `_objects` (and
         obj.Effects = d.Effects;                                   // D.5.2 contract
         if (d.Value is { } v) obj.Value = v;
         if (d.StackSize is { } s) obj.StackSize = s;
-        if (d.StackSizeMax is { } sm) obj.StackSizeMax = (int)sm;
+        if (d.StackSizeMax is { } sm) obj.StackSizeMax = sm;
         if (d.Burden is { } b) obj.Burden = b;
         if (d.ContainerId is { } c) obj.ContainerId = c;
         if (d.WielderId is { } w) obj.WielderId = w;