diff --git a/PlotLine.Tests/Program.cs b/PlotLine.Tests/Program.cs
index 3d4e6a5..e3665a8 100644
--- a/PlotLine.Tests/Program.cs
+++ b/PlotLine.Tests/Program.cs
@@ -176,6 +176,7 @@ static void ProjectHardDeleteClearsStoryIntelligenceDependenciesInTransaction()
 {
     var root = Path.Combine(AppContext.BaseDirectory, "../../../../PlotLine");
     var repository = File.ReadAllText(Path.Combine(root, "Data/Repositories.cs"));
+    var cascadeMigration = File.ReadAllText(Path.Combine(root, "Sql/159_Phase25D_ManuscriptSourceHardDeleteCascades.sql"));
 
     Assert(repository.Contains("using var transaction = connection.BeginTransaction()", StringComparison.Ordinal), "Project hard delete should be wrapped by a repository transaction.");
     Assert(repository.Contains("ProjectHardDeleteStoryIntelligenceDependencyCleanupSql", StringComparison.Ordinal), "Project hard delete should run scoped Story Intelligence dependency cleanup before the stored procedure.");
@@ -186,6 +187,10 @@ static void ProjectHardDeleteClearsStoryIntelligenceDependenciesInTransaction()
     Assert(repository.Contains("StoryMemoryProcessedSceneResults", StringComparison.Ordinal), "Hard delete cleanup should remove durable story memory scene-result rows.");
     Assert(repository.Contains("StoryMemoryImportPreferences", StringComparison.Ordinal), "Hard delete cleanup should remove durable story memory import rows.");
     Assert(repository.Contains("WHERE ProjectID = @ProjectID", StringComparison.Ordinal), "Hard delete cleanup must be scoped by project id.");
+    Assert(cascadeMigration.Contains("FK_SceneManuscriptSources_Scenes", StringComparison.Ordinal)
+        && cascadeMigration.Contains("REFERENCES dbo.Scenes(SceneID) ON DELETE CASCADE", StringComparison.Ordinal), "Scene manuscript source text should not block permanent scene deletion.");
+    Assert(cascadeMigration.Contains("FK_ManuscriptStructuralChapterSources_Chapters", StringComparison.Ordinal)
+        && cascadeMigration.Contains("REFERENCES dbo.Chapters(ChapterID) ON DELETE CASCADE", StringComparison.Ordinal), "Structural chapter source text should not block permanent chapter deletion.");
 }
 
 static void PermanentProjectDeleteKeepsArchiveAndNameSafetyGates()
diff --git a/PlotLine/Sql/159_Phase25D_ManuscriptSourceHardDeleteCascades.sql b/PlotLine/Sql/159_Phase25D_ManuscriptSourceHardDeleteCascades.sql
new file mode 100644
index 0000000..ac3d387
--- /dev/null
+++ b/PlotLine/Sql/159_Phase25D_ManuscriptSourceHardDeleteCascades.sql
@@ -0,0 +1,64 @@
+SET ANSI_NULLS ON;
+GO
+SET QUOTED_IDENTIFIER ON;
+GO
+
+IF OBJECT_ID(N'dbo.SceneManuscriptSources', N'U') IS NOT NULL
+    AND EXISTS
+    (
+        SELECT 1
+        FROM sys.foreign_keys
+        WHERE name = N'FK_SceneManuscriptSources_Scenes'
+            AND parent_object_id = OBJECT_ID(N'dbo.SceneManuscriptSources')
+            AND delete_referential_action_desc <> N'CASCADE'
+    )
+BEGIN
+    ALTER TABLE dbo.SceneManuscriptSources DROP CONSTRAINT FK_SceneManuscriptSources_Scenes;
+
+    ALTER TABLE dbo.SceneManuscriptSources WITH CHECK
+        ADD CONSTRAINT FK_SceneManuscriptSources_Scenes
+        FOREIGN KEY (SceneID) REFERENCES dbo.Scenes(SceneID) ON DELETE CASCADE;
+END;
+GO
+
+IF OBJECT_ID(N'dbo.SceneManuscriptSources', N'U') IS NOT NULL
+    AND NOT EXISTS
+    (
+        SELECT 1
+        FROM sys.foreign_keys
+        WHERE name = N'FK_SceneManuscriptSources_Scenes'
+            AND parent_object_id = OBJECT_ID(N'dbo.SceneManuscriptSources')
+            AND delete_referential_action_desc = N'CASCADE'
+    )
+    THROW 52010, 'Scene manuscript source hard-delete cascade was not applied.', 1;
+GO
+
+IF OBJECT_ID(N'dbo.ManuscriptStructuralChapterSources', N'U') IS NOT NULL
+    AND NOT EXISTS
+    (
+        SELECT 1
+        FROM sys.foreign_keys
+        WHERE name = N'FK_ManuscriptStructuralChapterSources_Chapters'
+            AND parent_object_id = OBJECT_ID(N'dbo.ManuscriptStructuralChapterSources')
+            AND delete_referential_action_desc = N'CASCADE'
+    )
+    THROW 52011, 'Structural chapter source hard-delete cascade was not applied.', 1;
+GO
+
+IF OBJECT_ID(N'dbo.ManuscriptStructuralChapterSources', N'U') IS NOT NULL
+    AND EXISTS
+    (
+        SELECT 1
+        FROM sys.foreign_keys
+        WHERE name = N'FK_ManuscriptStructuralChapterSources_Chapters'
+            AND parent_object_id = OBJECT_ID(N'dbo.ManuscriptStructuralChapterSources')
+            AND delete_referential_action_desc <> N'CASCADE'
+    )
+BEGIN
+    ALTER TABLE dbo.ManuscriptStructuralChapterSources DROP CONSTRAINT FK_ManuscriptStructuralChapterSources_Chapters;
+
+    ALTER TABLE dbo.ManuscriptStructuralChapterSources WITH CHECK
+        ADD CONSTRAINT FK_ManuscriptStructuralChapterSources_Chapters
+        FOREIGN KEY (ChapterID) REFERENCES dbo.Chapters(ChapterID) ON DELETE CASCADE;
+END;
+GO