microsoft · Evangelink · Jun 5, 2026 · May 25, 2026 · May 28, 2026 · Jun 1, 2026
diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
@@ -8,7 +8,7 @@ The codebase ships several distinct (but related) products. Knowing which produc
 
 - `src/Platform/Microsoft.Testing.Platform` — Microsoft.Testing.Platform (MTP), a lightweight, in-process test host that replaces VSTest. Most other folders under `src/Platform/` are MTP extensions (`TrxReport`, `CrashDump`, `HangDump`, `HotReload`, `Retry`, `Telemetry`, `HtmlReport`, `AzureDevOpsReport`, `MSBuild`, `VSTestBridge`, …).
 - `src/TestFramework` — MSTest itself: the public `Microsoft.VisualStudio.TestTools.UnitTesting` API (attributes, `Assert`, `TestContext`, …) plus `TestFramework.Extensions`.
-- `src/Adapter` — bridges MSTest to test hosts: `MSTest.TestAdapter` (VSTest adapter), `MSTestAdapter.PlatformServices` (platform-services abstraction shared by both hosts), and `MSTest.Engine` (MTP-native execution engine used by source-generated tests).
+- `src/Adapter` — bridges MSTest to test hosts: `MSTest.TestAdapter` (VSTest adapter) and `MSTestAdapter.PlatformServices` (platform-services abstraction shared by both hosts).
 - `src/Analyzers` — Roslyn analyzers and code fixes shipped as `MSTest.Analyzers`.
 - `src/Package/MSTest.Sdk` — the MSBuild project SDK that wires the pieces together for consumers.
 - `test/UnitTests/<Project>.UnitTests` — fast unit tests for each project.

diff --git a/.github/workflows/add-tests.md b/.github/workflows/add-tests.md
@@ -68,7 +68,6 @@ Analyze the pull request diff to identify source files that were added or modifi
    - `src/TestFramework/` → `test/UnitTests/TestFramework.UnitTests/`
    - `src/Adapter/MSTest.TestAdapter/` → `test/UnitTests/MSTestAdapter.UnitTests/`
    - `src/Adapter/MSTestAdapter.PlatformServices/` → `test/UnitTests/MSTestAdapter.PlatformServices.UnitTests/`
-   - `src/Adapter/MSTest.Engine/` → `test/UnitTests/MSTest.Engine.UnitTests/`
    - `src/Analyzers/MSTest.Analyzers/` → `test/UnitTests/MSTest.Analyzers.Tests/` (if exists)
    - `src/Analyzers/MSTest.SourceGeneration/` → `test/UnitTests/MSTest.SourceGeneration.UnitTests/`
    - `src/Platform/` → `test/UnitTests/` (find matching test project by name)

diff --git a/Directory.Build.props b/Directory.Build.props
@@ -50,12 +50,12 @@
 
   <!-- Versioning -->
   <PropertyGroup>
-    <MSTestEnginePreReleaseVersionLabel>alpha</MSTestEnginePreReleaseVersionLabel>
+    <MSTestSourceGenerationPreReleaseVersionLabel>alpha</MSTestSourceGenerationPreReleaseVersionLabel>
 
     <!--
       This is a early preview package, keep 2.0.0-alpha or similar suffix even in official builds.
     -->
-    <MSTestEngineVersionPrefix>2.0.0</MSTestEngineVersionPrefix>
+    <MSTestSourceGenerationVersionPrefix>2.0.0</MSTestSourceGenerationVersionPrefix>
   </PropertyGroup>
 
   <!-- Pack config -->

diff --git a/MSTest.slnf b/MSTest.slnf
@@ -6,7 +6,6 @@
       "samples\\FxExtensibility\\FxExtensibility.csproj",
       "samples\\NUnitPlayground\\NUnitPlayground.csproj",
       "samples\\Playground\\Playground.csproj",
-      "src\\Adapter\\MSTest.Engine\\MSTest.Engine.csproj",
       "src\\Adapter\\MSTest.TestAdapter\\MSTest.TestAdapter.csproj",
       "src\\Adapter\\MSTestAdapter.PlatformServices\\MSTestAdapter.PlatformServices.csproj",
       "src\\Analyzers\\MSTest.Analyzers.CodeFixes\\MSTest.Analyzers.CodeFixes.csproj",

diff --git a/NonWindowsTests.slnf b/NonWindowsTests.slnf
@@ -2,7 +2,6 @@
   "solution": {
     "path": "TestFx.slnx",
     "projects": [
-      "src\\Adapter\\MSTest.Engine\\MSTest.Engine.csproj",
       "src\\Adapter\\MSTest.TestAdapter\\MSTest.TestAdapter.csproj",
       "src\\Adapter\\MSTestAdapter.PlatformServices\\MSTestAdapter.PlatformServices.csproj",
       "src\\Analyzers\\MSTest.Analyzers.CodeFixes\\MSTest.Analyzers.CodeFixes.csproj",

diff --git a/TestFx.slnx b/TestFx.slnx
@@ -55,7 +55,6 @@
     <Project Path="src/Platform/Microsoft.Testing.Platform/Microsoft.Testing.Platform.csproj" />
   </Folder>
   <Folder Name="/src/2 - Adapter/">
-    <Project Path="src/Adapter/MSTest.Engine/MSTest.Engine.csproj" />
     <Project Path="src/Adapter/MSTest.TestAdapter/MSTest.TestAdapter.csproj" />
     <Project Path="src/Adapter/MSTestAdapter.PlatformServices/MSTestAdapter.PlatformServices.csproj" />
   </Folder>
@@ -133,7 +132,6 @@
     <Project Path="test/UnitTests/Microsoft.Testing.Platform.MSBuild.UnitTests/Microsoft.Testing.Platform.MSBuild.UnitTests.csproj" />
     <Project Path="test/UnitTests/Microsoft.Testing.Platform.UnitTests/Microsoft.Testing.Platform.UnitTests.csproj" />
     <Project Path="test/UnitTests/MSTest.Analyzers.UnitTests/MSTest.Analyzers.UnitTests.csproj" />
-    <Project Path="test/UnitTests/MSTest.Engine.UnitTests/MSTest.Engine.UnitTests.csproj" />
     <Project Path="test/UnitTests/MSTest.SelfRealExamples.UnitTests/MSTest.SelfRealExamples.UnitTests.csproj" />
     <Project Path="test/UnitTests/MSTest.SourceGeneration.UnitTests/MSTest.SourceGeneration.UnitTests.csproj" />
     <Project Path="test/UnitTests/MSTestAdapter.PlatformServices.UnitTests/MSTestAdapter.PlatformServices.UnitTests.csproj" />

diff --git a/docs/README.md b/docs/README.md
@@ -37,6 +37,10 @@ For technical reasoning and implementation details, you can refer to the list of
 - [DataSource Attribute Vs ITestDataSource](RFCs/007-DataSource-Attribute-VS-ITestDataSource.md)
 - [Test case timeout via runsettings](RFCs/008-TestCase-Timeout.md)
 
+## Design notes
+
+- [MSTest source generator — design](source-generator/design.md): scope, fallback categories, discovery limitations and trim/AOT story for the `MSTest.SourceGeneration` package.
+
 ## Releases
 
 You can find all features and bugs fixed in all our releases by looking at [releases.md](releases.md).