diff --git a/src/LibraryManager.Contracts/LibraryInstallationGoalState.cs b/src/LibraryManager.Contracts/LibraryInstallationGoalState.cs
index cac93d2d..4d9f4809 100644
--- a/src/LibraryManager.Contracts/LibraryInstallationGoalState.cs
+++ b/src/LibraryManager.Contracts/LibraryInstallationGoalState.cs
@@ -14,9 +14,10 @@ public class LibraryInstallationGoalState
         /// <summary>
         /// Initialize a new goal state from the desired installation state.
         /// </summary>
-        public LibraryInstallationGoalState(ILibraryInstallationState installationState)
+        public LibraryInstallationGoalState(ILibraryInstallationState installationState, Dictionary<string, string> installedFiles)
         {
             InstallationState = installationState;
+            InstalledFiles = installedFiles;
         }
 
         /// <summary>
@@ -27,7 +28,7 @@ public LibraryInstallationGoalState(ILibraryInstallationState installationState)
         /// <summary>
         /// Mapping from destination file to source file
         /// </summary>
-        public IDictionary<string, string> InstalledFiles { get; } = new Dictionary<string, string>();
+        public IDictionary<string, string> InstalledFiles { get; }
 
         /// <summary>
         /// Returns whether the goal is in an achieved state - that is, all files are up to date.
diff --git a/src/LibraryManager/Providers/BaseProvider.cs b/src/LibraryManager/Providers/BaseProvider.cs
index bc6fc2ea..496572ef 100644
--- a/src/LibraryManager/Providers/BaseProvider.cs
+++ b/src/LibraryManager/Providers/BaseProvider.cs
@@ -235,7 +235,6 @@ public async Task<OperationResult<LibraryInstallationGoalState>> GetInstallation
 
         private OperationResult<LibraryInstallationGoalState> GenerateGoalState(ILibraryInstallationState desiredState, ILibrary library)
         {
-            var goalState = new LibraryInstallationGoalState(desiredState);
             List<IError> errors = null;
 
             if (string.IsNullOrEmpty(desiredState.DestinationPath))
@@ -253,6 +252,7 @@ private OperationResult<LibraryInstallationGoalState> GenerateGoalState(ILibrary
                 outFiles = FileGlobbingUtility.ExpandFileGlobs(desiredState.Files, library.Files.Keys);
             }
 
+            Dictionary<string, string> installFiles = new();
             if (library.GetInvalidFiles(outFiles.ToList()) is IReadOnlyList<string> invalidFiles
                 && invalidFiles.Count > 0)
             {
@@ -275,9 +275,8 @@ private OperationResult<LibraryInstallationGoalState> GenerateGoalState(ILibrary
                 string sourceFile = GetCachedFileLocalPath(desiredState, outFile);
                 sourceFile = FileHelpers.NormalizePath(sourceFile);
 
-                // TODO: make goalState immutable
                 // map destination back to the library-relative file it originated from
-                goalState.InstalledFiles.Add(destinationFile, sourceFile);
+                installFiles.Add(destinationFile, sourceFile);
             }
 
             if (errors is not null)
@@ -285,6 +284,7 @@ private OperationResult<LibraryInstallationGoalState> GenerateGoalState(ILibrary
                 return OperationResult<LibraryInstallationGoalState>.FromErrors([.. errors]);
             }
 
+            var goalState = new LibraryInstallationGoalState(desiredState, installFiles);
             return OperationResult<LibraryInstallationGoalState>.FromSuccess(goalState);
         }
 
diff --git a/test/Microsoft.Web.LibraryManager.Vsix.Test/Shared/LibraryCommandServiceTest.cs b/test/Microsoft.Web.LibraryManager.Vsix.Test/Shared/LibraryCommandServiceTest.cs
index 3713b70c..990a6de8 100644
--- a/test/Microsoft.Web.LibraryManager.Vsix.Test/Shared/LibraryCommandServiceTest.cs
+++ b/test/Microsoft.Web.LibraryManager.Vsix.Test/Shared/LibraryCommandServiceTest.cs
@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.IO;
 using System.Text;
 using System.Threading;
@@ -34,8 +35,11 @@ public async Task UninstallAsync_DeletesFilesFromDisk()
                 Files = new[] { "test.js" },
                 DestinationPath = "testDestination",
             };
-            var testGoalState = new LibraryInstallationGoalState(testInstallationState);
-            testGoalState.InstalledFiles.Add(Path.Combine(mockInteraction.WorkingDirectory, "testDestination", "test.js"), Path.Combine(mockInteraction.WorkingDirectory, "test.js"));
+            Dictionary<string, string> installedFiles = new()
+            {
+                { Path.Combine(mockInteraction.WorkingDirectory, "testDestination", "test.js"), Path.Combine(mockInteraction.WorkingDirectory, "test.js")}
+            };
+            var testGoalState = new LibraryInstallationGoalState(testInstallationState, installedFiles);
             var mockDependencies = new Dependencies(mockInteraction, new IProvider[]
             {
                 new Mocks.Provider(mockInteraction)