diff --git a/docs/PROJECT-STRUCTURE.md b/docs/PROJECT-STRUCTURE.md
index a7149b3..b897687 100644
--- a/docs/PROJECT-STRUCTURE.md
+++ b/docs/PROJECT-STRUCTURE.md
@@ -182,6 +182,9 @@ decoded pixels.
 shared by VM presentation, graphics hosts, Godot, and tests.
 `engine/Age.Engine/Model/InputContracts.cs` owns neutral ADV auto-wait state and fullwidth text-edit request/result
 records shared by input hosts, timing policy, VM dispatch, Godot, and tests.
+`engine/Age.Engine/Model/AdvPresentationContracts.cs` owns neutral ADV wait-indicator configuration shared by VM
+dispatch, retained presentation, hosts, Godot, and tests. `engine/Age.Engine/Model/DiagnosticContracts.cs` owns
+the neutral synchronous diagnostic message transported between VM dispatch, diagnostic hosts, Godot, and tests.
 
 `engine/Age.Engine/Model/GfxState.cs` retains cross-domain retained-graphics coordination.
 `engine/Age.Engine/Model/GfxState.Contracts.cs` owns its public render, transition, diagnostic, persistence,
diff --git a/docs/remake-architecture-and-roadmap.md b/docs/remake-architecture-and-roadmap.md
index 04c65ff..d9e9aca 100644
--- a/docs/remake-architecture-and-roadmap.md
+++ b/docs/remake-architecture-and-roadmap.md
@@ -815,6 +815,13 @@ do not mix mechanical moves with semantic changes.
    twenty-three ADV members, required implementations, overload/default chains, existing hosts, and transport
    record locations remain behaviorally unchanged. Runtime validation remains green.
 
+   The eleventh bounded contract slice moved the unchanged `AdvWaitIndicatorConfig` and `DiagnosticMessage`
+   declarations from `Hosting` into domain-specific `Model` contract files. The retained wait-indicator presenter
+   no longer imports `Hosting`; two host-local consumers gained `Model` imports, and one test dropped its obsolete
+   fully qualified hosting name. Record shape, frame selection, diagnostic presentation, and runtime behavior
+   remain unchanged. This completes the planned runtime-contract split and neutral transport cleanup. Runtime
+   validation remains green.
+
 4. **Make the build graph express source ownership.** Stop linking production `.cs` files from `godot/` and
    `tools/movie-corpus-gate/` into `Age.Engine.Tests`. Extract the platform-neutral frontend/movie/diagnostic
    code into a small production project referenced by Godot, tests, and the corpus gate. Retain both existing
@@ -1173,10 +1180,9 @@ layer's rendering diverges from ADV; save layout.
 ---
 
 ## 8. Immediate next step
-Continue step 3 of the **codebase consolidation** maintenance slice: clarify runtime contracts without changing
-behavior or the aggregate host accepted by the VM. With diagnostic, lifecycle, audio, and movie contracts
-established beneath `IHost`, shared graphics/input transport neutral, and graphics/input/ADV contracts now
-separated, move the unchanged `AdvWaitIndicatorConfig` and `DiagnosticMessage` declarations from `Hosting` to
-`Model` next. Preserve all consumers while removing the remaining transport declarations from interface files.
+Begin step 4 of the **codebase consolidation** maintenance slice: make the build graph express source ownership
+without changing behavior. Introduce the production project boundary for platform-neutral frontend helpers now
+linked directly from `godot/` into `Age.Engine.Tests`, starting with the diagnostic/options helper cluster. Replace
+source links with project references while retaining both existing solution files and Godot export behavior.
 Concrete playthrough blockers may still preempt this bounded maintenance work; the consolidation effort does
 not replace Phase B gameplay validation or the open cross-platform gates.
diff --git a/engine/Age.Engine.Tests/AdvTextOpsTests.cs b/engine/Age.Engine.Tests/AdvTextOpsTests.cs
index 82af3e5..bb3b323 100644
--- a/engine/Age.Engine.Tests/AdvTextOpsTests.cs
+++ b/engine/Age.Engine.Tests/AdvTextOpsTests.cs
@@ -384,7 +384,7 @@ public class AdvTextOpsTests
 
         new VirtualMachine(script, table, host).Run();
 
-        Assert.Equal(new Age.Engine.Hosting.AdvWaitIndicatorConfig(1, 385, 140, 12, 0, 0, 30, 27, 12, 48),
+        Assert.Equal(new AdvWaitIndicatorConfig(1, 385, 140, 12, 0, 0, 30, 27, 12, 48),
                      Assert.Single(host.WaitIndicators));
     }
 
diff --git a/engine/Age.Engine/Hosting/CaptureHost.cs b/engine/Age.Engine/Hosting/CaptureHost.cs
index 1c953d1..817b54c 100644
--- a/engine/Age.Engine/Hosting/CaptureHost.cs
+++ b/engine/Age.Engine/Hosting/CaptureHost.cs
@@ -1,3 +1,5 @@
+using Age.Engine.Model;
+
 namespace Age.Engine.Hosting;
 public sealed class CaptureHost : IHost
 {
diff --git a/engine/Age.Engine/Hosting/IAdvHost.cs b/engine/Age.Engine/Hosting/IAdvHost.cs
index 1835a3d..1d9d5c6 100644
--- a/engine/Age.Engine/Hosting/IAdvHost.cs
+++ b/engine/Age.Engine/Hosting/IAdvHost.cs
@@ -2,21 +2,6 @@ using Age.Engine.Model;
 
 namespace Age.Engine.Hosting;
 
-public readonly record struct AdvWaitIndicatorConfig(
-    int LayoutSlot, int X, int Y, int SurfaceSlot,
-    int SourceX, int SourceY, int CellWidth, int CellHeight,
-    int TerminalFrame, long FramePeriodMs)
-{
-    /// <summary>Select the current atlas frame. TerminalFrame is the exclusive native upper bound,
-    /// so SYSTEM4's value 12 addresses the twelve cells 0 through 11.</summary>
-    public int FrameAt(long elapsedMs)
-    {
-        int frameCount = System.Math.Max(1, TerminalFrame);
-        long period = System.Math.Max(1, FramePeriodMs);
-        return (int)(System.Math.Max(0, elapsedMs) / period % frameCount);
-    }
-}
-
 public interface IAdvHost
 {
     void ShowText(int offset, string text);
diff --git a/engine/Age.Engine/Hosting/IDiagnosticHost.cs b/engine/Age.Engine/Hosting/IDiagnosticHost.cs
index 0a6d63a..85f327a 100644
--- a/engine/Age.Engine/Hosting/IDiagnosticHost.cs
+++ b/engine/Age.Engine/Hosting/IDiagnosticHost.cs
@@ -1,3 +1,5 @@
+using Age.Engine.Model;
+
 namespace Age.Engine.Hosting;
 
 public interface IDiagnosticHost
diff --git a/engine/Age.Engine/Hosting/IHost.cs b/engine/Age.Engine/Hosting/IHost.cs
index 5dc52f7..5619085 100644
--- a/engine/Age.Engine/Hosting/IHost.cs
+++ b/engine/Age.Engine/Hosting/IHost.cs
@@ -1,8 +1,5 @@
 namespace Age.Engine.Hosting;
 
-/// <summary>A synchronous AGE-owned diagnostic prompt after native body/context formatting.</summary>
-public readonly record struct DiagnosticMessage(string Caption, string Text);
-
 public interface IHost : IDiagnosticHost, ILifecycleHost, IAudioHost, IMovieHost, IGraphicsHost, IInputHost,
                          IAdvHost
 {
diff --git a/engine/Age.Engine/Model/AdvPresentationContracts.cs b/engine/Age.Engine/Model/AdvPresentationContracts.cs
new file mode 100644
index 0000000..eb2c4d3
--- /dev/null
+++ b/engine/Age.Engine/Model/AdvPresentationContracts.cs
@@ -0,0 +1,16 @@
+namespace Age.Engine.Model;
+
+public readonly record struct AdvWaitIndicatorConfig(
+    int LayoutSlot, int X, int Y, int SurfaceSlot,
+    int SourceX, int SourceY, int CellWidth, int CellHeight,
+    int TerminalFrame, long FramePeriodMs)
+{
+    /// <summary>Select the current atlas frame. TerminalFrame is the exclusive native upper bound,
+    /// so SYSTEM4's value 12 addresses the twelve cells 0 through 11.</summary>
+    public int FrameAt(long elapsedMs)
+    {
+        int frameCount = System.Math.Max(1, TerminalFrame);
+        long period = System.Math.Max(1, FramePeriodMs);
+        return (int)(System.Math.Max(0, elapsedMs) / period % frameCount);
+    }
+}
diff --git a/engine/Age.Engine/Model/DiagnosticContracts.cs b/engine/Age.Engine/Model/DiagnosticContracts.cs
new file mode 100644
index 0000000..56ca2ba
--- /dev/null
+++ b/engine/Age.Engine/Model/DiagnosticContracts.cs
@@ -0,0 +1,4 @@
+namespace Age.Engine.Model;
+
+/// <summary>A synchronous AGE-owned diagnostic prompt after native body/context formatting.</summary>
+public readonly record struct DiagnosticMessage(string Caption, string Text);
diff --git a/engine/Age.Engine/Text/RetainedAdvWaitIndicatorPresentation.cs b/engine/Age.Engine/Text/RetainedAdvWaitIndicatorPresentation.cs
index a928df3..ff315d2 100644
--- a/engine/Age.Engine/Text/RetainedAdvWaitIndicatorPresentation.cs
+++ b/engine/Age.Engine/Text/RetainedAdvWaitIndicatorPresentation.cs
@@ -1,4 +1,3 @@
-using Age.Engine.Hosting;
 using Age.Engine.Model;
 
 namespace Age.Engine.Text;