diff --git a/docs/PROJECT-STRUCTURE.md b/docs/PROJECT-STRUCTURE.md
index 8fae564..4f31df9 100644
--- a/docs/PROJECT-STRUCTURE.md
+++ b/docs/PROJECT-STRUCTURE.md
@@ -158,7 +158,9 @@ through project references rather than compiling duplicate linked sources. The f
 audio-timeline alignment, movie-surface registry, and RIFF/WAVE sanitizer; only the `Himegari` and
 `Age.Engine.Tests` assemblies receive explicit friend access to that internal API. FFmpeg native interop and the
 asynchronous/paced decoder also live here; the `Age.MovieCorpusGate` tool receives friend access to the native
-frame-source seam and references this project rather than compiling an interop source link.
+frame-source seam and references this project rather than compiling source links. Reusable movie-corpus discovery,
+decode-gate, and report contracts live here as well; `tools/movie-corpus-gate/Program.cs` remains only the
+command-line entry point and output writer.
 
 `godot/GodotAdvHost.cs` retains cross-domain host coordination. Its partial-class companion
 `godot/GodotAdvHost.AdvText.cs` owns live/retained ADV text, surface glyph rasterization and caching,
diff --git a/docs/remake-architecture-and-roadmap.md b/docs/remake-architecture-and-roadmap.md
index 6a1bfeb..19c178c 100644
--- a/docs/remake-architecture-and-roadmap.md
+++ b/docs/remake-architecture-and-roadmap.md
@@ -848,6 +848,13 @@ do not mix mechanical moves with semantic changes.
    failure handling, and teardown remain unchanged. Engine, Godot, and corpus-gate builds plus runtime validation
    remain green.
 
+   The fourth bounded build-graph slice moved the unchanged reusable movie-corpus discovery, decode-gate, and
+   report implementation from `tools/movie-corpus-gate/` into `Age.Engine.Frontend`. The tool retains only its
+   command-line entry point and consumes the internal gate through its existing friend/project boundary; tests use
+   the same production implementation through their project reference. The final cross-project production `.cs`
+   source link is gone, completing the planned build-graph ownership cleanup. Engine, Godot, and corpus-gate
+   builds plus runtime validation remain green.
+
 5. **Close repository-policy and storage gaps.** Add an explicit project license, third-party notices and
    checksums/provenance for committed binaries, consistent editor/build policy, a pinned .NET SDK, and a
    CI entry point built on the same validation driver. Remove the empty workspace-root `.git` directory and
@@ -1201,10 +1208,10 @@ layer's rendering diverges from ADV; save layout.
 ---
 
 ## 8. Immediate next step
-Begin step 4 of the **codebase consolidation** maintenance slice: make the build graph express source ownership
-without changing behavior. Move the reusable `MovieCorpusGate.cs` implementation from
-`tools/movie-corpus-gate/` into `Age.Engine.Frontend` next. Leave the tool's `Program.cs` as its command-line entry
-point, remove the final test source link, preserve the internal friend boundary, and verify that no production
-`.cs` files are compiled through cross-project links.
+Begin step 5 of the **codebase consolidation** maintenance slice with a non-destructive repository-policy and
+storage audit. Inventory current license/notice state, committed third-party binaries and provenance, editor/build
+policy, SDK pinning, CI entry points, repository roots/ignored output nests, and remote/backup configuration.
+Report exact gaps and a bounded implementation order before choosing a license, changing external state, deleting
+or compacting repositories, or removing any ignored output.
 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/tools/movie-corpus-gate/MovieCorpusGate.cs b/engine/Age.Engine.Frontend/MovieCorpusGate.cs
similarity index 100%
rename from tools/movie-corpus-gate/MovieCorpusGate.cs
rename to engine/Age.Engine.Frontend/MovieCorpusGate.cs
diff --git a/engine/Age.Engine.Tests/Age.Engine.Tests.csproj b/engine/Age.Engine.Tests/Age.Engine.Tests.csproj
index 4744193..d22ec7e 100644
--- a/engine/Age.Engine.Tests/Age.Engine.Tests.csproj
+++ b/engine/Age.Engine.Tests/Age.Engine.Tests.csproj
@@ -24,7 +24,6 @@
     <ProjectReference Include="..\Age.Engine\Age.Engine.csproj" />
     <ProjectReference Include="..\Age.Engine.Frontend\Age.Engine.Frontend.csproj" />
     <ProjectReference Include="..\Age.Engine.Text.Windows\Age.Engine.Text.Windows.csproj" />
-    <Compile Include="..\..\tools\movie-corpus-gate\MovieCorpusGate.cs" Link="MovieCorpusGate.cs" />
   </ItemGroup>
 
 </Project>