diff --git a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorConfiguration.cs b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorConfiguration.cs
index a1b1ba4b487..70356d7d1fa 100644
--- a/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorConfiguration.cs
+++ b/src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/RazorConfiguration.cs
@@ -1,8 +1,12 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
+using System.Threading;
+using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNetCore.Razor.Language;
@@ -21,6 +25,10 @@ public sealed record class RazorConfiguration(
         LanguageServerFlags: null,
         UseConsolidatedMvcViews: true);
 
+    private Checksum? _checksum;
+    internal Checksum Checksum
+        => _checksum ?? InterlockedOperations.Initialize(ref _checksum, CalculateChecksum());
+
     public bool Equals(RazorConfiguration? other)
         => other is not null &&
            LanguageVersion == other.LanguageVersion &&
@@ -39,4 +47,33 @@ public override int GetHashCode()
         hash.Add(LanguageServerFlags);
         return hash;
     }
+
+    internal void AppendChecksum(Checksum.Builder builder)
+    {
+        builder.AppendData(LanguageVersion.Major);
+        builder.AppendData(LanguageVersion.Minor);
+        builder.AppendData(ConfigurationName);
+        builder.AppendData(UseConsolidatedMvcViews);
+
+        if (LanguageServerFlags is null)
+        {
+            builder.AppendNull();
+        }
+        else
+        {
+            builder.AppendData(LanguageServerFlags.ForceRuntimeCodeGeneration);
+        }
+
+        foreach (var extension in Extensions)
+        {
+            builder.AppendData(extension.ExtensionName);
+        }
+    }
+
+    private Checksum CalculateChecksum()
+    {
+        var builder = new Checksum.Builder();
+        AppendChecksum(builder);
+        return builder.FreeAndGetChecksum();
+    }
 }
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace/RazorWorkspaceListenerBase.Work.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace/RazorWorkspaceListenerBase.Work.cs
new file mode 100644
index 00000000000..b6a612b952a
--- /dev/null
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace/RazorWorkspaceListenerBase.Work.cs
@@ -0,0 +1,13 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using Microsoft.CodeAnalysis;
+
+namespace Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace;
+
+public abstract partial class RazorWorkspaceListenerBase
+{
+    internal abstract record Work(ProjectId ProjectId);
+    internal sealed record UpdateWork(ProjectId ProjectId) : Work(ProjectId);
+    internal sealed record RemovalWork(ProjectId ProjectId, string IntermediateOutputPath) : Work(ProjectId);
+}
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace/RazorWorkspaceListenerBase.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace/RazorWorkspaceListenerBase.cs
index 7ab3ecf2a4b..1a1c0e4952c 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace/RazorWorkspaceListenerBase.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace/RazorWorkspaceListenerBase.cs
@@ -3,19 +3,24 @@
 
 using System.Collections.Immutable;
 using System.Diagnostics;
+using Microsoft.AspNetCore.Razor.Telemetry;
 using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis;
 using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace;
 
-public abstract class RazorWorkspaceListenerBase : IDisposable
+public abstract partial class RazorWorkspaceListenerBase : IDisposable
 {
     private static readonly TimeSpan s_debounceTime = TimeSpan.FromMilliseconds(500);
     private readonly CancellationTokenSource _disposeTokenSource = new();
 
     private readonly ILogger _logger;
     private readonly AsyncBatchingWorkQueue<Work> _workQueue;
+    private readonly CompilationTagHelperResolver _tagHelperResolver = new(NoOpTelemetryReporter.Instance);
+
+    // Only modified in the batching work queue so no need to lock for mutation
+    private readonly Dictionary<ProjectId, Checksum?> _projectChecksums = new();
 
     // Use an immutable dictionary for ImmutableInterlocked operations. The value isn't checked, just
     // the existance of the key so work is only done for projects with dynamic files.
@@ -23,11 +28,6 @@ public abstract class RazorWorkspaceListenerBase : IDisposable
 
     private Stream? _stream;
     private Workspace? _workspace;
-    private bool _disposed;
-
-    internal record Work(ProjectId ProjectId);
-    internal record UpdateWork(ProjectId ProjectId) : Work(ProjectId);
-    internal record RemovalWork(ProjectId ProjectId, string IntermediateOutputPath) : Work(ProjectId);
 
     private protected RazorWorkspaceListenerBase(ILogger logger)
     {
@@ -42,22 +42,21 @@ void IDisposable.Dispose()
         if (_workspace is not null)
         {
             _workspace.WorkspaceChanged -= Workspace_WorkspaceChanged;
+            _workspace = null;
         }
 
-        if (_disposed)
+        if (_disposeTokenSource.IsCancellationRequested)
         {
             _logger.LogInformation("Disposal was called twice");
             return;
         }
 
-        _disposed = true;
         _logger.LogInformation("Tearing down named pipe for pid {pid}", Process.GetCurrentProcess().Id);
 
         _disposeTokenSource.Cancel();
         _disposeTokenSource.Dispose();
 
         _stream?.Dispose();
-        _stream = null;
     }
 
     public void NotifyDynamicFile(ProjectId projectId)
@@ -93,7 +92,7 @@ private protected void EnsureInitialized(Workspace workspace, Func<Stream> creat
         }
 
         // Early check for disposal just to reduce any work further
-        if (_disposed)
+        if (_disposeTokenSource.IsCancellationRequested)
         {
             return;
         }
@@ -173,7 +172,7 @@ private void Workspace_WorkspaceChanged(object? sender, WorkspaceChangeEventArgs
         //
         void EnqueueUpdate(Project? project)
         {
-            if (_disposed ||
+            if (_disposeTokenSource.IsCancellationRequested ||
                 project is not
                 {
                     Language: LanguageNames.CSharp
@@ -195,7 +194,7 @@ void RemoveProject(Project project)
         {
             // Remove project is called from Workspace.Changed, while other notifications of _projectsWithDynamicFile
             // are handled with NotifyDynamicFile. Use ImmutableInterlocked here to be sure the updates happen
-            // in a thread safe manner since those are not assumed to be the same thread. 
+            // in a thread safe manner since those are not assumed to be the same thread.
             if (ImmutableInterlocked.TryRemove(ref _projectsWithDynamicFile, project.Id, out var _))
             {
                 var intermediateOutputPath = Path.GetDirectoryName(project.CompilationOutputInfo.AssemblyPath);
@@ -219,50 +218,47 @@ void RemoveProject(Project project)
     /// </remarks>
     private protected async virtual ValueTask ProcessWorkAsync(ImmutableArray<Work> work, CancellationToken cancellationToken)
     {
-        // Capture as locals here. Cancellation of the work queue still need to propogate. The cancellation
-        // token itself represents the work queue halting, but this will help avoid any assumptions about nullability of locals
-        // through the use in this function.
-        var stream = _stream;
-        var solution = _workspace?.CurrentSolution;
-
-        cancellationToken.ThrowIfCancellationRequested();
-
-        // Early bail check for if we are disposed or somewhere in the middle of disposal 
-        if (_disposed || stream is null || solution is null)
+        if (cancellationToken.IsCancellationRequested)
         {
             _logger.LogTrace("Skipping work due to disposal");
             return;
         }
 
+        var stream = _stream.AssumeNotNull();
+        var solution = _workspace.AssumeNotNull().CurrentSolution;
+
         await CheckConnectionAsync(stream, cancellationToken).ConfigureAwait(false);
-        await ProcessWorkCoreAsync(work, stream, solution, _logger, cancellationToken).ConfigureAwait(false);
+        await ProcessWorkCoreAsync(work, stream, solution, cancellationToken).ConfigureAwait(false);
     }
 
-    private static async Task ProcessWorkCoreAsync(ImmutableArray<Work> work, Stream stream, Solution solution, ILogger logger, CancellationToken cancellationToken)
+    private async Task ProcessWorkCoreAsync(ImmutableArray<Work> work, Stream stream, Solution solution, CancellationToken cancellationToken)
     {
         foreach (var unit in work)
         {
             try
             {
-                cancellationToken.ThrowIfCancellationRequested();
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return;
+                }
 
                 if (unit is RemovalWork removalWork)
                 {
-                    await ReportRemovalAsync(stream, removalWork, logger, cancellationToken).ConfigureAwait(false);
+                    await ReportRemovalAsync(stream, removalWork, _logger, cancellationToken).ConfigureAwait(false);
                 }
 
                 var project = solution.GetProject(unit.ProjectId);
                 if (project is null)
                 {
-                    logger.LogTrace("Project {projectId} is not in workspace", unit.ProjectId);
+                    _logger.LogTrace("Project {projectId} is not in workspace", unit.ProjectId);
                     continue;
                 }
 
-                await ReportUpdateProjectAsync(stream, project, logger, cancellationToken).ConfigureAwait(false);
+                await ReportUpdateProjectAsync(stream, project, cancellationToken).ConfigureAwait(false);
             }
             catch (Exception ex) when (ex is not OperationCanceledException)
             {
-                logger.LogError(ex, "Encountered exception while processing unit: {message}", ex.Message);
+                _logger.LogError(ex, "Encountered exception while processing unit: {message}", ex.Message);
             }
         }
 
@@ -272,22 +268,37 @@ private static async Task ProcessWorkCoreAsync(ImmutableArray<Work> work, Stream
         }
         catch (Exception ex)
         {
-            logger.LogError(ex, "Encountered error flusingh stream");
+            _logger.LogError(ex, "Encountered error flushing stream");
         }
     }
 
-    private static async Task ReportUpdateProjectAsync(Stream stream, Project project, ILogger logger, CancellationToken cancellationToken)
+    private async Task ReportUpdateProjectAsync(Stream stream, Project project, CancellationToken cancellationToken)
     {
-        logger.LogTrace("Serializing information for {projectId}", project.Id);
-        var projectInfo = await RazorProjectInfoFactory.ConvertAsync(project, logger, cancellationToken).ConfigureAwait(false);
-        if (projectInfo is null)
+        _logger.LogTrace("Serializing information for {projectId}", project.Id);
+        var projectPath = Path.GetDirectoryName(project.FilePath);
+        if (projectPath is null)
         {
-            logger.LogTrace("Skipped writing data for {projectId}", project.Id);
+            _logger.LogInformation("projectPath is null, skip update for {projectId}", project.Id);
             return;
         }
 
-        stream.WriteProjectInfoAction(ProjectInfoAction.Update);
-        await stream.WriteProjectInfoAsync(projectInfo, cancellationToken).ConfigureAwait(false);
+        var checksum = _projectChecksums.GetOrAdd(project.Id, static _ => null);
+        var projectEngine = RazorProjectInfoHelpers.GetProjectEngine(project, projectPath);
+        var tagHelpers = await _tagHelperResolver.GetTagHelpersAsync(project, projectEngine, cancellationToken).ConfigureAwait(false);
+        var projectInfo = RazorProjectInfoHelpers.TryConvert(project, projectPath, tagHelpers);
+        if (projectInfo is not null)
+        {
+            if (checksum == projectInfo.Checksum)
+            {
+                _logger.LogInformation("Checksum for {projectId} did not change. Skipped sending update", project.Id);
+                return;
+            }
+
+            _projectChecksums[project.Id] = projectInfo.Checksum;
+
+            stream.WriteProjectInfoAction(ProjectInfoAction.Update);
+            await stream.WriteProjectInfoAsync(projectInfo, cancellationToken).ConfigureAwait(false);
+        }
     }
 
     private static Task ReportRemovalAsync(Stream stream, RemovalWork unit, ILogger logger, CancellationToken cancellationToken)
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/ProjectExtensions.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/ProjectExtensions.cs
new file mode 100644
index 00000000000..5bff1fb7f44
--- /dev/null
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/ProjectExtensions.cs
@@ -0,0 +1,38 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+#if !NET
+using System;
+#endif
+
+using System.Diagnostics;
+using Microsoft.AspNetCore.Razor.ProjectSystem;
+using Microsoft.AspNetCore.Razor.Utilities;
+using Microsoft.CodeAnalysis;
+
+namespace Microsoft.AspNetCore.Razor;
+
+internal static class ProjectExtensions
+{
+    public static ProjectKey ToProjectKey(this Project project)
+    {
+        var intermediateOutputPath = FilePathNormalizer.GetNormalizedDirectoryName(project.CompilationOutputInfo.AssemblyPath);
+        return new(intermediateOutputPath);
+    }
+
+    /// <summary>
+    /// Returns <see langword="true"/> if this <see cref="ProjectKey"/> matches the given <see cref="Project"/>.
+    /// </summary>
+    public static bool Matches(this ProjectKey projectKey, Project project)
+    {
+        // In order to perform this check, we are relying on the fact that Id will always end with a '/',
+        // because it is guaranteed to be normalized. However, CompilationOutputInfo.AssemblyPath will
+        // contain the assembly file name, which AreDirectoryPathsEquivalent will shave off before comparing.
+        // So, AreDirectoryPathsEquivalent will return true when Id is "C:/my/project/path/"
+        // and the assembly path is "C:\my\project\path\assembly.dll"
+
+        Debug.Assert(projectKey.Id.EndsWith('/'), $"This method can't be called if {nameof(projectKey.Id)} is not a normalized directory path.");
+
+        return FilePathNormalizer.AreDirectoryPathsEquivalent(projectKey.Id, project.CompilationOutputInfo.AssemblyPath);
+    }
+}
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/ProjectSystem/ProjectWorkspaceState.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/ProjectSystem/ProjectWorkspaceState.cs
index b4c2c9548fb..b775aea7491 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/ProjectSystem/ProjectWorkspaceState.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/ProjectSystem/ProjectWorkspaceState.cs
@@ -5,6 +5,7 @@
 using System.Collections.Immutable;
 using System.Linq;
 using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.Extensions.Internal;
 
@@ -54,4 +55,13 @@ public override int GetHashCode()
 
         return hash.CombinedHash;
     }
+
+    internal void AppendChecksum(Checksum.Builder builder)
+    {
+        builder.AppendData((int)CSharpLanguageVersion);
+        foreach (var tagHelper in TagHelpers)
+        {
+            builder.AppendData(tagHelper.Checksum);
+        }
+    }
 }
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/ProjectSystem/RazorProjectInfo.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/ProjectSystem/RazorProjectInfo.cs
index 86158c6ceb9..d38ddcd1d11 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/ProjectSystem/RazorProjectInfo.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/ProjectSystem/RazorProjectInfo.cs
@@ -1,30 +1,16 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
-using System;
-using System.Buffers;
 using System.Collections.Immutable;
-using System.IO;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
-using MessagePack;
-using MessagePack.Resolvers;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.Serialization;
-using Microsoft.AspNetCore.Razor.Serialization.MessagePack.Resolvers;
+using Microsoft.AspNetCore.Razor.Utilities;
 using Microsoft.CodeAnalysis;
-using Microsoft.Extensions.Internal;
 
 namespace Microsoft.AspNetCore.Razor.ProjectSystem;
 
 internal sealed record class RazorProjectInfo
 {
-    private static readonly MessagePackSerializerOptions s_options = MessagePackSerializerOptions.Standard
-        .WithResolver(CompositeResolver.Create(
-            RazorProjectInfoResolver.Instance,
-            StandardResolver.Instance));
-
     public ProjectKey ProjectKey { get; init; }
     public string FilePath { get; init; }
     public RazorConfiguration Configuration { get; init; }
@@ -33,6 +19,10 @@ internal sealed record class RazorProjectInfo
     public ProjectWorkspaceState ProjectWorkspaceState { get; init; }
     public ImmutableArray<DocumentSnapshotHandle> Documents { get; init; }
 
+    private Checksum? _checksum;
+    internal Checksum Checksum
+        => _checksum ?? InterlockedOperations.Initialize(ref _checksum, ComputeChecksum());
+
     public RazorProjectInfo(
         ProjectKey projectKey,
         string filePath,
@@ -51,46 +41,29 @@ public RazorProjectInfo(
         Documents = documents.NullToEmpty();
     }
 
-    public bool Equals(RazorProjectInfo? other)
-        => other is not null &&
-           ProjectKey == other.ProjectKey &&
-           FilePath == other.FilePath &&
-           Configuration.Equals(other.Configuration) &&
-           RootNamespace == other.RootNamespace &&
-           DisplayName == other.DisplayName &&
-           ProjectWorkspaceState.Equals(other.ProjectWorkspaceState) &&
-           Documents.SequenceEqual(other.Documents);
+    public bool Equals(RazorConfiguration? other)
+        => other is not null && Checksum.Equals(other.Checksum);
 
     public override int GetHashCode()
-    {
-        var hash = HashCodeCombiner.Start();
+        => Checksum.GetHashCode();
 
-        hash.Add(ProjectKey);
-        hash.Add(FilePath);
-        hash.Add(Configuration);
-        hash.Add(RootNamespace);
-        hash.Add(DisplayName);
-        hash.Add(ProjectWorkspaceState);
-        hash.Add(Documents);
-
-        return hash.CombinedHash;
-    }
-
-    public byte[] Serialize()
-        => MessagePackSerializer.Serialize(this, s_options);
-
-    public void SerializeTo(IBufferWriter<byte> bufferWriter)
-        => MessagePackSerializer.Serialize(bufferWriter, this, s_options);
+    private Checksum ComputeChecksum()
+    {
+        var builder = new Checksum.Builder();
 
-    public void SerializeTo(Stream stream)
-        => MessagePackSerializer.Serialize(stream, this, s_options);
+        builder.AppendData(FilePath);
+        builder.AppendData(ProjectKey.Id);
+        builder.AppendData(DisplayName);
+        builder.AppendData(RootNamespace);
 
-    public static RazorProjectInfo? DeserializeFrom(ReadOnlyMemory<byte> buffer)
-        => MessagePackSerializer.Deserialize<RazorProjectInfo>(buffer, s_options);
+        Configuration.AppendChecksum(builder);
+        foreach (var document in Documents)
+        {
+            document.AppendChecksum(builder);
+        }
 
-    public static RazorProjectInfo? DeserializeFrom(Stream stream)
-        => MessagePackSerializer.Deserialize<RazorProjectInfo>(stream, s_options);
+        ProjectWorkspaceState.AppendChecksum(builder);
 
-    public static ValueTask<RazorProjectInfo> DeserializeFromAsync(Stream stream, CancellationToken cancellationToken)
-        => MessagePackSerializer.DeserializeAsync<RazorProjectInfo>(stream, s_options, cancellationToken);
+        return builder.FreeAndGetChecksum();
+    }
 }
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace/RazorProjectInfoFactory.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/RazorProjectInfoHelpers.cs
similarity index 68%
rename from src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace/RazorProjectInfoFactory.cs
rename to src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/RazorProjectInfoHelpers.cs
index c99a25ec283..ff0a4dc7ab6 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace/RazorProjectInfoFactory.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/RazorProjectInfoHelpers.cs
@@ -1,9 +1,12 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Immutable;
 using System.Diagnostics.CodeAnalysis;
-using System.Runtime.InteropServices;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.AspNetCore.Razor.ProjectEngineHost;
@@ -15,60 +18,43 @@
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.Diagnostics;
 using Microsoft.CodeAnalysis.Razor;
-using Microsoft.Extensions.Logging;
 
-namespace Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace;
+namespace Microsoft.AspNetCore.Razor;
 
-internal static class RazorProjectInfoFactory
+internal static class RazorProjectInfoHelpers
 {
-    private static readonly StringComparison s_stringComparison;
-
-    static RazorProjectInfoFactory()
-    {
-        s_stringComparison = RuntimeInformation.IsOSPlatform(OSPlatform.Linux)
-            ? StringComparison.Ordinal
-            : StringComparison.OrdinalIgnoreCase;
-    }
-
-    public static async Task<RazorProjectInfo?> ConvertAsync(Project project, ILogger? logger, CancellationToken cancellationToken)
+    public static RazorProjectInfo? TryConvert(
+        Project project,
+        string projectPath,
+        ImmutableArray<TagHelperDescriptor> tagHelpers)
     {
-        var projectPath = Path.GetDirectoryName(project.FilePath);
-        if (projectPath is null)
-        {
-            logger?.LogInformation("projectPath is null, skip conversion for {projectId}", project.Id);
-            return null;
-        }
-
-        var intermediateOutputPath = Path.GetDirectoryName(project.CompilationOutputInfo.AssemblyPath);
-        if (intermediateOutputPath is null)
-        {
-            logger?.LogInformation("intermediatePath is null, skip conversion for {projectId}", project.Id);
-            return null;
-        }
-
-        // First, lets get the documents, because if there aren't any, we can skip out early
         var documents = GetDocuments(project, projectPath);
 
         // Not a razor project
         if (documents.Length == 0)
         {
-            if (project.DocumentIds.Count == 0)
-            {
-                logger?.LogInformation("No razor documents for {projectId}", project.Id);
-            }
-            else
-            {
-                logger?.LogTrace("No documents in {projectId}", project.Id);
-            }
-            
             return null;
         }
 
+        var options = project.AnalyzerOptions.AnalyzerConfigOptionsProvider;
+        var (razorConfiguration, rootNamespace) = ComputeRazorConfigurationOptions(options);
+
         var csharpLanguageVersion = (project.ParseOptions as CSharpParseOptions)?.LanguageVersion ?? LanguageVersion.Default;
+        var projectWorkspaceState = ProjectWorkspaceState.Create(tagHelpers, csharpLanguageVersion);
 
-        var options = project.AnalyzerOptions.AnalyzerConfigOptionsProvider;
-        var configuration = ComputeRazorConfigurationOptions(options, logger, out var defaultNamespace);
+        return new RazorProjectInfo(
+            projectKey: project.ToProjectKey(),
+            filePath: project.FilePath.AssumeNotNull(),
+            razorConfiguration,
+            rootNamespace,
+            displayName: project.Name,
+            projectWorkspaceState,
+            documents);
+    }
 
+    public static async Task<ProjectWorkspaceState?> GetWorkspaceStateAsync(Project project, RazorConfiguration configuration, string? defaultNamespace, string projectPath, CancellationToken cancellationToken)
+    {
+        var csharpLanguageVersion = (project.ParseOptions as CSharpParseOptions)?.LanguageVersion ?? LanguageVersion.Default;
         var fileSystem = RazorProjectFileSystem.Create(projectPath);
 
         var defaultConfigure = (RazorProjectEngineBuilder builder) =>
@@ -92,19 +78,35 @@ static RazorProjectInfoFactory()
         var resolver = new CompilationTagHelperResolver(NoOpTelemetryReporter.Instance);
         var tagHelpers = await resolver.GetTagHelpersAsync(project, engine, cancellationToken).ConfigureAwait(false);
 
-        var projectWorkspaceState = ProjectWorkspaceState.Create(tagHelpers, csharpLanguageVersion);
+        return ProjectWorkspaceState.Create(tagHelpers, csharpLanguageVersion);
+    }
 
-        return new RazorProjectInfo(
-            projectKey: new ProjectKey(intermediateOutputPath),
-            filePath: project.FilePath!,
-            configuration: configuration,
-            rootNamespace: defaultNamespace,
-            displayName: project.Name,
-            projectWorkspaceState: projectWorkspaceState,
-            documents: documents);
+    public static RazorProjectEngine GetProjectEngine(Project project, string projectPath)
+    {
+        var options = project.AnalyzerOptions.AnalyzerConfigOptionsProvider;
+        var (configuration, rootNamespace) = ComputeRazorConfigurationOptions(options);
+        var csharpLanguageVersion = (project.ParseOptions as CSharpParseOptions)?.LanguageVersion ?? LanguageVersion.Default;
+        var fileSystem = RazorProjectFileSystem.Create(projectPath);
+        var defaultConfigure = (RazorProjectEngineBuilder builder) =>
+        {
+            if (rootNamespace is not null)
+            {
+                builder.SetRootNamespace(rootNamespace);
+            }
+
+            builder.SetCSharpLanguageVersion(csharpLanguageVersion);
+            builder.SetSupportLocalizedComponentNames(); // ProjectState in MS.CA.Razor.Workspaces does this, so I'm doing it too!
+        };
+
+        var engineFactory = ProjectEngineFactories.DefaultProvider.GetFactory(configuration);
+
+        return engineFactory.Create(
+            configuration,
+            fileSystem,
+            configure: defaultConfigure);
     }
 
-    private static RazorConfiguration ComputeRazorConfigurationOptions(AnalyzerConfigOptionsProvider options, ILogger? logger, out string defaultNamespace)
+    public static (RazorConfiguration razorConfiguration, string rootNamespace) ComputeRazorConfigurationOptions(AnalyzerConfigOptionsProvider options)
     {
         // See RazorSourceGenerator.RazorProviders.cs
 
@@ -119,18 +121,17 @@ private static RazorConfiguration ComputeRazorConfigurationOptions(AnalyzerConfi
         if (!globalOptions.TryGetValue("build_property.RazorLangVersion", out var razorLanguageVersionString) ||
             !RazorLanguageVersion.TryParse(razorLanguageVersionString, out var razorLanguageVersion))
         {
-            logger?.LogTrace("Using default of latest language version");
             razorLanguageVersion = RazorLanguageVersion.Latest;
         }
 
         var razorConfiguration = new RazorConfiguration(razorLanguageVersion, configurationName, Extensions: [], UseConsolidatedMvcViews: true);
 
-        defaultNamespace = rootNamespace ?? "ASP"; // TODO: Source generator does this. Do we want it?
+        rootNamespace ??= "ASP"; // TODO: Source generator does this. Do we want it?
 
-        return razorConfiguration;
+        return (razorConfiguration, rootNamespace);
     }
 
-    internal static ImmutableArray<DocumentSnapshotHandle> GetDocuments(Project project, string projectPath)
+    public static ImmutableArray<DocumentSnapshotHandle> GetDocuments(Project project, string projectPath)
     {
         using var documents = new PooledArrayBuilder<DocumentSnapshotHandle>();
 
@@ -168,7 +169,7 @@ internal static ImmutableArray<DocumentSnapshotHandle> GetDocuments(Project proj
     private static string GetTargetPath(string documentFilePath, string normalizedProjectPath)
     {
         var targetFilePath = FilePathNormalizer.Normalize(documentFilePath);
-        if (targetFilePath.StartsWith(normalizedProjectPath, s_stringComparison))
+        if (targetFilePath.StartsWith(normalizedProjectPath, FilePathComparison.Instance))
         {
             // Make relative
             targetFilePath = documentFilePath[normalizedProjectPath.Length..];
@@ -182,14 +183,14 @@ private static string GetTargetPath(string documentFilePath, string normalizedPr
 
     private static bool TryGetFileKind(string filePath, [NotNullWhen(true)] out string? fileKind)
     {
-        var extension = Path.GetExtension(filePath.AsSpan());
+        var extension = Path.GetExtension(filePath);
 
-        if (extension.Equals(".cshtml", s_stringComparison))
+        if (extension.Equals(".cshtml", FilePathComparison.Instance))
         {
             fileKind = FileKinds.Legacy;
             return true;
         }
-        else if (extension.Equals(".razor", s_stringComparison))
+        else if (extension.Equals(".razor", FilePathComparison.Instance))
         {
             fileKind = FileKinds.GetComponentFileKindFromFilePath(filePath);
             return true;
@@ -213,11 +214,9 @@ private static bool TryGetRazorFileName(string? filePath, [NotNullWhen(true)] ou
         const string generatedRazorExtension = $".razor{suffix}";
         const string generatedCshtmlExtension = $".cshtml{suffix}";
 
-        var path = filePath.AsSpan();
-
         // Generated files have a path like: virtualcsharp-razor:///e:/Scratch/RazorInConsole/Goo.cshtml__virtual.cs
-        if (path.StartsWith(prefix, StringComparison.OrdinalIgnoreCase) &&
-            (path.EndsWith(generatedRazorExtension, s_stringComparison) || path.EndsWith(generatedCshtmlExtension, s_stringComparison)))
+        if (filePath.StartsWith(prefix, StringComparison.OrdinalIgnoreCase) &&
+            (filePath.EndsWith(generatedRazorExtension, FilePathComparison.Instance) || filePath.EndsWith(generatedCshtmlExtension, FilePathComparison.Instance)))
         {
             // Go through the file path normalizer because it also does Uri decoding, and we're converting from a Uri to a path
             // but "new Uri(filePath).LocalPath" seems wasteful
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Serialization/DocumentSnapshotHandle.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Serialization/DocumentSnapshotHandle.cs
index 9b4bafb1f27..f848b283680 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Serialization/DocumentSnapshotHandle.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Serialization/DocumentSnapshotHandle.cs
@@ -1,6 +1,16 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
+using Microsoft.AspNetCore.Razor.Utilities;
+
 namespace Microsoft.AspNetCore.Razor.Serialization;
 
-internal record DocumentSnapshotHandle(string FilePath, string TargetPath, string FileKind);
+internal record DocumentSnapshotHandle(string FilePath, string TargetPath, string FileKind)
+{
+    internal void AppendChecksum(Checksum.Builder builder)
+    {
+        builder.AppendData(FilePath);
+        builder.AppendData(TargetPath);
+        builder.AppendData(FileKind);
+    }
+}
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Serialization/RazorMessagePackSerializer.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Serialization/RazorMessagePackSerializer.cs
new file mode 100644
index 00000000000..d708d6500bb
--- /dev/null
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Serialization/RazorMessagePackSerializer.cs
@@ -0,0 +1,42 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using System;
+using System.Buffers;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using MessagePack;
+using MessagePack.Resolvers;
+using Microsoft.AspNetCore.Razor.Serialization.MessagePack.Resolvers;
+
+namespace Microsoft.AspNetCore.Razor.Serialization;
+
+internal static class RazorMessagePackSerializer
+{
+    private static readonly MessagePackSerializerOptions s_options = MessagePackSerializerOptions.Standard
+        .WithResolver(CompositeResolver.Create(
+            RazorProjectInfoResolver.Instance,
+            StandardResolver.Instance));
+
+    public static byte[] Serialize<T>(T instance)
+        => MessagePackSerializer.Serialize(instance, s_options);
+
+    public static void SerializeTo<T>(T instance, IBufferWriter<byte> bufferWriter)
+        => MessagePackSerializer.Serialize(bufferWriter, instance, s_options);
+
+    public static void SerializeTo<T>(T instance, Stream stream)
+        => MessagePackSerializer.Serialize(stream, instance, s_options);
+
+    public static T? DeserializeFrom<T>(ReadOnlyMemory<byte> buffer)
+        => MessagePackSerializer.Deserialize<T>(buffer, s_options);
+
+    public static T? DeserializeFrom<T>(ReadOnlySequence<byte> buffer)
+        => MessagePackSerializer.Deserialize<T>(buffer, s_options);
+
+    public static T? DeserializeFrom<T>(Stream stream)
+        => MessagePackSerializer.Deserialize<T>(stream, s_options);
+
+    public static ValueTask<T> DeserializeFromAsync<T>(Stream stream, CancellationToken cancellationToken)
+        => MessagePackSerializer.DeserializeAsync<T>(stream, s_options, cancellationToken);
+}
diff --git a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Utilities/StreamExtensions.NetCore.cs b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Utilities/StreamExtensions.NetCore.cs
index 81abc7a2a16..855306bca98 100644
--- a/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Utilities/StreamExtensions.NetCore.cs
+++ b/src/Razor/src/Microsoft.AspNetCore.Razor.ProjectEngineHost/Utilities/StreamExtensions.NetCore.cs
@@ -2,6 +2,7 @@
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
 using Microsoft.AspNetCore.Razor.ProjectSystem;
+using Microsoft.AspNetCore.Razor.Serialization;
 using System;
 using System.Buffers;
 using System.Diagnostics;
@@ -73,9 +74,16 @@ public static Task<string> ReadProjectInfoRemovalAsync(this Stream stream, Cance
         return stream.ReadStringAsync(encoding: null, cancellationToken);
     }
 
+    public static async Task WriteWithSizeAsync<T>(this Stream stream, T value, CancellationToken cancellationToken)
+    {
+        var bytes = RazorMessagePackSerializer.Serialize(value);
+        WriteSize(stream, bytes.Length);
+        await stream.WriteAsync(bytes, 0, bytes.Length, cancellationToken).ConfigureAwait(false);
+    }
+
     public static async Task WriteProjectInfoAsync(this Stream stream, RazorProjectInfo projectInfo, CancellationToken cancellationToken)
     {
-        var bytes = projectInfo.Serialize();
+        var bytes = RazorMessagePackSerializer.Serialize(projectInfo);
         WriteSize(stream, bytes.Length);
         await stream.WriteAsync(bytes, 0, bytes.Length, cancellationToken).ConfigureAwait(false);
     }
@@ -90,7 +98,7 @@ public static async Task WriteProjectInfoAsync(this Stream stream, RazorProjectI
         // The array may be larger than the bytes read so make sure to trim accordingly.
         var projectInfoMemory = projectInfoBytes.AsMemory(0, sizeToRead);
 
-        return RazorProjectInfo.DeserializeFrom(projectInfoMemory);
+        return RazorMessagePackSerializer.DeserializeFrom<RazorProjectInfo>(projectInfoMemory);
     }
 
     public static void WriteSize(this Stream stream, int length)
diff --git a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/Extensions.cs b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/Extensions.cs
index 34b050477a0..f27ab8f9a04 100644
--- a/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/Extensions.cs
+++ b/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/ProjectSystem/Extensions.cs
@@ -1,15 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT license. See License.txt in the project root for license information.
 
-#if !NET
-using System;
-#endif
-
-using System.Diagnostics;
 using Microsoft.AspNetCore.Razor;
-using Microsoft.AspNetCore.Razor.ProjectSystem;
 using Microsoft.AspNetCore.Razor.Serialization;
-using Microsoft.AspNetCore.Razor.Utilities;
 
 namespace Microsoft.CodeAnalysis.Razor.ProjectSystem;
 
@@ -17,26 +10,4 @@ internal static class Extensions
 {
     public static DocumentSnapshotHandle ToHandle(this IDocumentSnapshot snapshot)
         => new(snapshot.FilePath.AssumeNotNull(), snapshot.TargetPath.AssumeNotNull(), snapshot.FileKind.AssumeNotNull());
-
-    public static ProjectKey ToProjectKey(this Project project)
-    {
-        var intermediateOutputPath = FilePathNormalizer.GetNormalizedDirectoryName(project.CompilationOutputInfo.AssemblyPath);
-        return new(intermediateOutputPath);
-    }
-
-    /// <summary>
-    /// Returns <see langword="true"/> if this <see cref="ProjectKey"/> matches the given <see cref="Project"/>.
-    /// </summary>
-    public static bool Matches(this ProjectKey projectKey, Project project)
-    {
-        // In order to perform this check, we are relying on the fact that Id will always end with a '/',
-        // because it is guaranteed to be normalized. However, CompilationOutputInfo.AssemblyPath will
-        // contain the assembly file name, which AreDirectoryPathsEquivalent will shave off before comparing.
-        // So, AreDirectoryPathsEquivalent will return true when Id is "C:/my/project/path/"
-        // and the assembly path is "C:\my\project\path\assembly.dll"
-
-        Debug.Assert(projectKey.Id.EndsWith('/'), $"This method can't be called if {nameof(projectKey.Id)} is not a normalized directory path.");
-
-        return FilePathNormalizer.AreDirectoryPathsEquivalent(projectKey.Id, project.CompilationOutputInfo.AssemblyPath);
-    }
 }
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/ProjectSystem/FallbackProjectManager.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/ProjectSystem/FallbackProjectManager.cs
index 09130e8cb44..2803a39d311 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/ProjectSystem/FallbackProjectManager.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/ProjectSystem/FallbackProjectManager.cs
@@ -5,6 +5,7 @@
 using System.ComponentModel.Composition;
 using System.IO;
 using System.Threading;
+using Microsoft.AspNetCore.Razor;
 using Microsoft.AspNetCore.Razor.ProjectSystem;
 using Microsoft.AspNetCore.Razor.Telemetry;
 using Microsoft.AspNetCore.Razor.Utilities;
diff --git a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/VsSolutionUpdatesProjectSnapshotChangeTrigger.cs b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/VsSolutionUpdatesProjectSnapshotChangeTrigger.cs
index c1e9de5988f..55ba43f16f7 100644
--- a/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/VsSolutionUpdatesProjectSnapshotChangeTrigger.cs
+++ b/src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/VsSolutionUpdatesProjectSnapshotChangeTrigger.cs
@@ -6,6 +6,7 @@
 using System.Linq;
 using System.Runtime.InteropServices;
 using System.Threading;
+using Microsoft.AspNetCore.Razor;
 using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Microsoft.CodeAnalysis.Razor.Workspaces;
 using Microsoft.VisualStudio.Razor.Extensions;
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace.Test/RazorProjectInfoSerializerTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace.Test/RazorProjectInfoSerializerTest.cs
index 465d490de1f..a56d2cf705a 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace.Test/RazorProjectInfoSerializerTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace.Test/RazorProjectInfoSerializerTest.cs
@@ -21,7 +21,7 @@ public void GeneratedDocument()
                     .WithFilePath("virtualcsharp-razor:///e:/Scratch/RazorInConsole/Goo.cshtml__virtual.cs")
                     .Project;
 
-        var documents = RazorProjectInfoFactory.GetDocuments(project, "temp");
+        var documents = RazorProjectInfoHelpers.GetDocuments(project, "temp");
 
         Assert.Single(documents);
     }
@@ -35,7 +35,7 @@ public void AdditionalDocument()
 
         project = workspace.CurrentSolution.GetProject(project.Id)!;
 
-        var documents = RazorProjectInfoFactory.GetDocuments(project, "temp");
+        var documents = RazorProjectInfoHelpers.GetDocuments(project, "temp");
 
         Assert.Single(documents);
     }
@@ -53,7 +53,7 @@ public void AdditionalAndGeneratedDocument()
             .WithFilePath("virtualcsharp-razor:///e:/Scratch/RazorInConsole/Another.cshtml__virtual.cs")
             .Project;
 
-        var documents = RazorProjectInfoFactory.GetDocuments(project, "temp");
+        var documents = RazorProjectInfoHelpers.GetDocuments(project, "temp");
 
         Assert.Single(documents);
     }
@@ -71,7 +71,7 @@ public void AdditionalNonRazorAndGeneratedDocument()
             .WithFilePath("virtualcsharp-razor:///e:/Scratch/RazorInConsole/Another.cshtml__virtual.cs")
             .Project;
 
-        var documents = RazorProjectInfoFactory.GetDocuments(project, "temp");
+        var documents = RazorProjectInfoHelpers.GetDocuments(project, "temp");
 
         Assert.Single(documents);
     }
@@ -85,7 +85,7 @@ public void NormalDocument()
             .WithFilePath("e:/Scratch/RazorInConsole/Goo.cs")
             .Project;
 
-        var documents = RazorProjectInfoFactory.GetDocuments(project, "temp");
+        var documents = RazorProjectInfoHelpers.GetDocuments(project, "temp");
 
         Assert.Empty(documents);
     }
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace.Test/RazorWorkspaceListenerTest.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace.Test/RazorWorkspaceListenerTest.cs
index 8fe48a38dce..d57248e9043 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace.Test/RazorWorkspaceListenerTest.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.ExternalAccess.RoslynWorkspace.Test/RazorWorkspaceListenerTest.cs
@@ -256,6 +256,57 @@ public async Task TestSerialization()
         Assert.Equal(intermediateDirectory, await readerStream.ReadProjectInfoRemovalAsync(CancellationToken.None));
     }
 
+    [Fact]
+    public async Task CSharpDocumentAdded_DoesNotUpdate()
+    {
+        using var workspace = new AdhocWorkspace(CodeAnalysis.Host.Mef.MefHostServices.DefaultHost);
+
+        using var listener = new TestRazorWorkspaceListener();
+        listener.EnsureInitialized(workspace);
+
+        var project = workspace.AddProject("TestProject", LanguageNames.CSharp);
+        listener.NotifyDynamicFile(project.Id);
+
+        await listener.WaitForDebounceAsync();
+
+        Assert.Equal(1, listener.SerializeCalls[project.Id]);
+        Assert.Equal(1, listener.WorkspaceChangedEvents);
+
+        var document = project.AddDocument("TestDocument", "class TestDocument { }");
+        Assert.True(workspace.TryApplyChanges(document.Project.Solution));
+
+        // We can't wait for debounce here, because it won't happen, but if we don't wait for _something_ we won't know
+        // if the test fails, so a delay is annoyingly necessary.
+        await Task.Delay(500);
+
+        Assert.Equal(2, listener.WorkspaceChangedEvents);
+        Assert.Equal(1, listener.SerializeCalls[project.Id]);
+    }
+
+    [Fact]
+    public async Task RazorFileAdded_DoesUpdate()
+    {
+        using var workspace = new AdhocWorkspace(CodeAnalysis.Host.Mef.MefHostServices.DefaultHost);
+
+        using var listener = new TestRazorWorkspaceListener();
+        listener.EnsureInitialized(workspace);
+
+        var project = workspace.AddProject("TestProject", LanguageNames.CSharp);
+        listener.NotifyDynamicFile(project.Id);
+
+        await listener.WaitForDebounceAsync();
+
+        Assert.Equal(1, listener.SerializeCalls[project.Id]);
+        Assert.Equal(1, listener.WorkspaceChangedEvents);
+
+        workspace.AddDocument(DocumentInfo.Create(DocumentId.CreateNewId(project.Id), @"Page.razor", filePath: @"C:\test\Page.razor"));
+
+        await listener.WaitForDebounceAsync();
+
+        Assert.Equal(2, listener.WorkspaceChangedEvents);
+        Assert.Equal(2, listener.SerializeCalls[project.Id]);
+    }
+
     private class TestRazorWorkspaceListener : RazorWorkspaceListenerBase
     {
         private ConcurrentDictionary<ProjectId, int> _serializeCalls = new();
@@ -265,6 +316,7 @@ private class TestRazorWorkspaceListener : RazorWorkspaceListenerBase
 
         public ConcurrentDictionary<ProjectId, int> SerializeCalls => _serializeCalls;
         public ConcurrentDictionary<ProjectId, int> RemoveCalls => _removeCalls;
+        public int WorkspaceChangedEvents { get; private set; }
 
         public TestRazorWorkspaceListener()
             : base(NullLoggerFactory.Instance.CreateLogger(""))
@@ -274,6 +326,7 @@ public TestRazorWorkspaceListener()
         public void EnsureInitialized(Workspace workspace)
         {
             EnsureInitialized(workspace, static () => Stream.Null);
+            workspace.WorkspaceChanged += (s, a) => { WorkspaceChangedEvents++; };
         }
 
         private protected override ValueTask ProcessWorkAsync(ImmutableArray<Work> work, CancellationToken cancellationToken)
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.ProjectEngineHost.Test/ProjectInfoChecksumTests.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.ProjectEngineHost.Test/ProjectInfoChecksumTests.cs
new file mode 100644
index 00000000000..66cfd0297ac
--- /dev/null
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.ProjectEngineHost.Test/ProjectInfoChecksumTests.cs
@@ -0,0 +1,97 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Razor.Language;
+using Microsoft.AspNetCore.Razor.ProjectSystem;
+using Microsoft.AspNetCore.Razor.Serialization;
+using Microsoft.AspNetCore.Razor.Test.Common;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Razor.ProjectEngineHost.Test;
+
+public class ProjectInfoChecksumTests
+{
+    [Fact]
+    public void CheckSame()
+    {
+        var info1 = CreateInfo();
+        var info2 = CreateInfo();
+
+        Assert.Equal(info1.Checksum, info2.Checksum);
+    }
+
+    [Fact]
+    public void Change_ProjectKey()
+    {
+        var info1 = CreateInfo();
+        var info2 = info1 with { ProjectKey = new ProjectKey("Test2") };
+
+        Assert.NotEqual(info1.Checksum, info2.Checksum);
+    }
+
+    [Fact]
+    public void Change_FilePath()
+    {
+        var info1 = CreateInfo();
+        var info2 = info1 with { FilePath = @"C:\test\test2.csproj" };
+
+        Assert.NotEqual(info1.Checksum, info2.Checksum);
+    }
+
+    [Fact]
+    public void Change_RootNamespace()
+    {
+        var info1 = CreateInfo();
+        var info2 = info1 with { RootNamespace = "TestNamespace2" };
+
+        Assert.NotEqual(info1.Checksum, info2.Checksum);
+    }
+
+    [Fact]
+    public void Change_DisplayName()
+    {
+        var info1 = CreateInfo();
+        var info2 = info1 with { DisplayName = "Test2 (tfm)" };
+
+        Assert.NotEqual(info1.Checksum, info2.Checksum);
+    }
+
+    [Fact]
+    public void Change_Configuration()
+    {
+        var info1 = CreateInfo();
+        var info2 = info1 with { Configuration = new RazorConfiguration(RazorLanguageVersion.Latest, "TestConfiguration2", []) };
+
+        Assert.NotEqual(info1.Checksum, info2.Checksum);
+    }
+
+    [Fact]
+    public void Change_ProjectWorkspaceState()
+    {
+        var info1 = CreateInfo();
+        var info2 = info1 with { ProjectWorkspaceState = ProjectWorkspaceState.Create(RazorTestResources.BlazorServerAppTagHelpers, CodeAnalysis.CSharp.LanguageVersion.CSharp10) };
+
+        Assert.NotEqual(info1.Checksum, info2.Checksum);
+    }
+
+    [Fact]
+    public void Change_Documents()
+    {
+        var info1 = CreateInfo();
+        var info2 = info1 with { Documents = info1.Documents.Add(new DocumentSnapshotHandle(@"C:\test\home.razor", @"C:\test\lib\net8.0", FileKinds.Component)) };
+
+        Assert.NotEqual(info1.Checksum, info2.Checksum);
+    }
+
+    RazorProjectInfo CreateInfo()
+    {
+        return new RazorProjectInfo(
+            new ProjectKey("Test"),
+            @"C:\test\test.csproj",
+            new RazorConfiguration(RazorLanguageVersion.Latest, "TestConfiguration", []),
+            "TestNamespace",
+            "Test (tfm)",
+            ProjectWorkspaceState.Create(RazorTestResources.BlazorServerAppTagHelpers, CodeAnalysis.CSharp.LanguageVersion.Latest),
+            []);
+    }
+}
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.ProjectEngineHost.Test/RazorConfigurationChecksumTests.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.ProjectEngineHost.Test/RazorConfigurationChecksumTests.cs
new file mode 100644
index 00000000000..67845df4c5c
--- /dev/null
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.ProjectEngineHost.Test/RazorConfigurationChecksumTests.cs
@@ -0,0 +1,65 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT license. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Razor.Language;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Razor.ProjectEngineHost.Test;
+
+public class RazorConfigurationChecksumTests
+{
+    [Fact]
+    public void CheckSame()
+    {
+        var config1 = GetConfiguration();
+        var config2 = GetConfiguration();
+
+        Assert.Equal(config1.Checksum, config2.Checksum);
+    }
+
+    [Fact]
+    public void Change_RazorLanguageVersion()
+    {
+        var config1 = GetConfiguration();
+        var config2 = config1 with { LanguageVersion = RazorLanguageVersion.Version_2_1 };
+
+        Assert.NotEqual(config1.Checksum, config2.Checksum);
+    }
+
+    [Fact]
+    public void Change_ConfigurationName()
+    {
+        var config1 = GetConfiguration();
+        var config2 = config1 with { ConfigurationName = "Configuration2" };
+
+        Assert.NotEqual(config1.Checksum, config2.Checksum);
+    }
+
+    [Fact]
+    public void Change_Extensions()
+    {
+        var config1 = GetConfiguration();
+        var config2 = config1 with { Extensions = config1.Extensions.Add(new RazorExtension("TestExtension2")) };
+
+        Assert.NotEqual(config1.Checksum, config2.Checksum);
+    }
+
+    [Fact]
+    public void Change_UseConsolidatedMvcViews()
+    {
+        var config1 = GetConfiguration();
+        var config2 = config1 with { UseConsolidatedMvcViews = !config1.UseConsolidatedMvcViews };
+
+        Assert.NotEqual(config1.Checksum, config2.Checksum);
+    }
+
+    private RazorConfiguration GetConfiguration()
+    {
+        return new RazorConfiguration(
+            RazorLanguageVersion.Latest,
+            "Configuration",
+            [new RazorExtension("TestExtension")],
+            new LanguageServerFlags(ForceRuntimeCodeGeneration: true),
+            UseConsolidatedMvcViews: false);
+    }
+}
diff --git a/src/Razor/test/Microsoft.AspNetCore.Razor.ProjectEngineHost.Test/StreamExtensionTests.NetCore.cs b/src/Razor/test/Microsoft.AspNetCore.Razor.ProjectEngineHost.Test/StreamExtensionTests.NetCore.cs
index 8895137d798..bbaecd1749f 100644
--- a/src/Razor/test/Microsoft.AspNetCore.Razor.ProjectEngineHost.Test/StreamExtensionTests.NetCore.cs
+++ b/src/Razor/test/Microsoft.AspNetCore.Razor.ProjectEngineHost.Test/StreamExtensionTests.NetCore.cs
@@ -88,7 +88,7 @@ public async Task SerializeProjectInfo()
             projectWorkspaceState,
             [new DocumentSnapshotHandle(@"C:\test\document.razor", @"document.razor", FileKinds.Component)]);
 
-        var bytesToSerialize = projectInfo.Serialize();
+        var bytesToSerialize = RazorMessagePackSerializer.Serialize(projectInfo);
 
         await stream.WriteProjectInfoAsync(projectInfo, default);