diff --git a/src/Analyzers/MSTest.AotReflection.SourceGeneration/Generators/MetadataRegistryEmitter.cs b/src/Analyzers/MSTest.AotReflection.SourceGeneration/Generators/MetadataRegistryEmitter.cs
index e7ae151cb8..d62a57defd 100644
--- a/src/Analyzers/MSTest.AotReflection.SourceGeneration/Generators/MetadataRegistryEmitter.cs
+++ b/src/Analyzers/MSTest.AotReflection.SourceGeneration/Generators/MetadataRegistryEmitter.cs
@@ -1,7 +1,8 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using MSTest.AotReflection.SourceGeneration.Helpers;
+using Microsoft.VisualStudio.TestPlatform.MSTestAdapter.PlatformServices.SourceGeneration.Helpers;
+
 using MSTest.AotReflection.SourceGeneration.Model;
 
 namespace MSTest.AotReflection.SourceGeneration.Generators;
diff --git a/src/Analyzers/MSTest.AotReflection.SourceGeneration/Helpers/IndentedStringBuilder.cs b/src/Analyzers/MSTest.AotReflection.SourceGeneration/Helpers/IndentedStringBuilder.cs
deleted file mode 100644
index 6899b7cce4..0000000000
--- a/src/Analyzers/MSTest.AotReflection.SourceGeneration/Helpers/IndentedStringBuilder.cs
+++ /dev/null
@@ -1,88 +0,0 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
-// Licensed under the MIT license. See LICENSE file in the project root for full license information.
-
-namespace MSTest.AotReflection.SourceGeneration.Helpers;
-
-/// <summary>
-/// A small <see cref="StringBuilder"/> wrapper that tracks an indentation level so the
-/// generated code stays readable. Kept private to this PoC to avoid pulling in the
-/// equivalent helper that lives in <c>MSTest.SourceGeneration</c>.
-/// </summary>
-internal sealed class IndentedStringBuilder
-{
-    private const string IndentUnit = "    ";
-    private readonly StringBuilder _builder = new();
-    private int _indent;
-    private bool _needsIndent = true;
-
-    public IndentedStringBuilder AppendLine(string value)
-    {
-        EnsureIndent();
-        _builder.AppendLine(value);
-        _needsIndent = true;
-        return this;
-    }
-
-    public IndentedStringBuilder AppendLine()
-    {
-        _builder.AppendLine();
-        _needsIndent = true;
-        return this;
-    }
-
-    public IndentedStringBuilder Append(string value)
-    {
-        EnsureIndent();
-        _builder.Append(value);
-        return this;
-    }
-
-    public IDisposable Block(string? header = null)
-    {
-        if (header is not null)
-        {
-            AppendLine(header);
-        }
-
-        AppendLine("{");
-        _indent++;
-        return new BlockScope(this);
-    }
-
-    public override string ToString() => _builder.ToString();
-
-    private void EnsureIndent()
-    {
-        if (!_needsIndent)
-        {
-            return;
-        }
-
-        for (int i = 0; i < _indent; i++)
-        {
-            _builder.Append(IndentUnit);
-        }
-
-        _needsIndent = false;
-    }
-
-    private sealed class BlockScope : IDisposable
-    {
-        private readonly IndentedStringBuilder _owner;
-        private bool _closed;
-
-        public BlockScope(IndentedStringBuilder owner) => _owner = owner;
-
-        public void Dispose()
-        {
-            if (_closed)
-            {
-                return;
-            }
-
-            _closed = true;
-            _owner._indent--;
-            _owner.AppendLine("}");
-        }
-    }
-}
diff --git a/src/Analyzers/MSTest.AotReflection.SourceGeneration/MSTest.AotReflection.SourceGeneration.csproj b/src/Analyzers/MSTest.AotReflection.SourceGeneration/MSTest.AotReflection.SourceGeneration.csproj
index dc9bbade05..b88c34a107 100644
--- a/src/Analyzers/MSTest.AotReflection.SourceGeneration/MSTest.AotReflection.SourceGeneration.csproj
+++ b/src/Analyzers/MSTest.AotReflection.SourceGeneration/MSTest.AotReflection.SourceGeneration.csproj
@@ -33,4 +33,9 @@
     <InternalsVisibleTo Include="MSTest.AotReflection.SourceGeneration.UnitTests" Key="$(VsPublicKey)" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Compile Include="..\MSTest.SourceGeneration\Helpers\Constants.cs" Link="Helpers\Constants.cs" />
+    <Compile Include="..\MSTest.SourceGeneration\Helpers\IndentedStringBuilder.cs" Link="Helpers\IndentedStringBuilder.cs" />
+  </ItemGroup>
+
 </Project>
diff --git a/src/Analyzers/MSTest.SourceGeneration/Helpers/IndentedStringBuilder.cs b/src/Analyzers/MSTest.SourceGeneration/Helpers/IndentedStringBuilder.cs
index 6b7937ade5..cfe869617f 100644
--- a/src/Analyzers/MSTest.SourceGeneration/Helpers/IndentedStringBuilder.cs
+++ b/src/Analyzers/MSTest.SourceGeneration/Helpers/IndentedStringBuilder.cs
@@ -4,9 +4,8 @@
 namespace Microsoft.VisualStudio.TestPlatform.MSTestAdapter.PlatformServices.SourceGeneration.Helpers;
 
 /// <summary>
-/// Small helper that produces indented source text. Mirrors the helper used by the existing
-/// MSTest.SourceGeneration project so that the generated output is consistent with the rest of
-/// the MSTest source generators.
+/// Canonical source-generator indentation helper. This file is linked by
+/// MSTest.AotReflection.SourceGeneration so both generators use deterministic newlines.
 /// </summary>
 internal sealed class IndentedStringBuilder
 {
@@ -17,30 +16,40 @@ internal sealed class IndentedStringBuilder
 
     public int IndentationLevel { get; internal set; }
 
-    public void Append(string value)
+    public IndentedStringBuilder Append(string value)
     {
         MaybeAppendIndent();
         _builder.Append(value);
         _needsIndent = false;
+
+        return this;
     }
 
-    public void AppendLine()
+    public IndentedStringBuilder AppendLine()
     {
         _builder.Append(Constants.NewLine);
         _needsIndent = true;
+
+        return this;
     }
 
-    public void AppendLine(string value)
+    public IndentedStringBuilder AppendLine(string value)
     {
         MaybeAppendIndent();
         _builder.Append(value);
         _builder.Append(Constants.NewLine);
         _needsIndent = true;
+
+        return this;
     }
 
-    public IDisposable AppendBlock(string header)
+    public IDisposable Block(string? header = null)
     {
-        AppendLine(header);
+        if (header is not null)
+        {
+            AppendLine(header);
+        }
+
         AppendLine("{");
         IndentationLevel++;