diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 5ccfb2cc..556511e1 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -20,6 +20,8 @@ env:
   ENABLE_DIAGNOSTICS: false
   #COREHOST_TRACE: 1
   COREHOST_TRACEFILE: corehosttrace.log
+  MULTI_TARGET_DIRECTORY: tooling/MultiTarget
+  HEADS_DIRECTORY: tooling/ProjectHeads
 
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
@@ -91,7 +93,6 @@ jobs:
   project-template:
     runs-on: windows-latest
     env:
-      HEADS_DIRECTORY: tooling/ProjectHeads
       PROJECT_DIRECTORY: tooling/ProjectTemplate
 
     steps:
@@ -141,7 +142,6 @@ jobs:
   new-experiment:
     runs-on: windows-latest
     env:
-      HEADS_DIRECTORY: tooling/ProjectHeads
       PROJECT_DIRECTORY: tooling/ProjectTemplate
       TEST_PROJECT_NAME: CiTestExp
       TEST_PROJECT_DIRECTORY: components/CiTestExp
@@ -238,7 +238,6 @@ jobs:
   wasm-linux:
     runs-on: ubuntu-latest
     env:
-      HEADS_DIRECTORY: tooling/ProjectHeads
       TEST_PROJECT_NAME: CiTestExp
 
     steps:
@@ -299,3 +298,110 @@ jobs:
         with:
           name: linux-logs
           path: ./**/*.*log
+
+  # Modified copy from build step at https://github.com/CommunityToolkit/Windows/blob/main/.github/workflows/build.yml#L52-L152
+  main-repo:
+    runs-on: windows-latest
+
+    # See https://docs.github.com/actions/using-jobs/using-a-matrix-for-your-jobs
+    strategy:
+      fail-fast: false # prevent one matrix pipeline from being cancelled if one fails, we want them both to run to completion.
+      matrix:
+        repo: [Windows, Labs-Windows]
+        platform: [WinUI2, WinUI3]
+
+    env:
+      # faux-ternary expression to select which platforms to build for each platform vs. duplicating step below.
+      TARGET_PLATFORMS: ${{ matrix.platform != 'WinUI3' && 'all' || 'all-uwp' }}
+      TEST_PLATFORM: ${{ matrix.platform != 'WinUI3' && 'UWP' || 'WinAppSdk' }}
+
+    # Steps represent a sequence of tasks that will be executed as part of the job
+    steps:
+      - name: Install .NET SDK v${{ env.DOTNET_VERSION }}
+        uses: actions/setup-dotnet@v3
+        with:
+          dotnet-version: ${{ env.DOTNET_VERSION }}
+
+      - name: .NET Info (if diagnostics)
+        if: ${{ env.ENABLE_DIAGNOSTICS == 'true' }}
+        run: dotnet --info
+
+      # Modified - Check out the main repo's repository first
+      - name: Checkout ${{ matrix.repo }} Repository
+        uses: actions/checkout@v3
+        with:
+          repository: CommunityToolkit/${{ matrix.repo }}
+          ref: main
+
+      # Checks-out Current tooling changes as the submodule
+      - name: Checkout Tooling Repository
+        uses: actions/checkout@v3
+        with:
+          path: tooling
+          clean: false
+
+      # TODO: Everything below these two checkout steps are the same, can we next in a yml for a composited build?
+      # Restore Tools from Manifest list in the Repository
+      - name: Restore dotnet tools
+        run: dotnet tool restore
+
+      - name: Run Uno Check to Install Dependencies
+        run: dotnet tool run uno-check --ci --fix --non-interactive --skip wsl --skip androidemulator --verbose
+
+      - name: Add msbuild to PATH
+        uses: microsoft/setup-msbuild@v1.3.1
+
+      - name: Enable ${{ env.TARGET_PLATFORMS }} TargetFrameworks
+        working-directory: ./${{ env.MULTI_TARGET_DIRECTORY }}
+        run: powershell -version 5.1 -command "./UseTargetFrameworks.ps1 ${{ env.TARGET_PLATFORMS }}" -ErrorAction Stop
+
+      - name: Generate solution w/ ${{ env.TEST_PLATFORM }} Tests
+        working-directory: ./
+        run: powershell -version 5.1 -command "./tooling/GenerateAllSolution.ps1 -IncludeHeads ${{ env.TEST_PLATFORM }}${{ env.ENABLE_DIAGNOSTICS == 'true' && ' -UseDiagnostics' || '' }}" -ErrorAction Stop
+
+      - name: Enable Uno.WinUI (in WinUI3 matrix only)
+        working-directory: ./${{ env.MULTI_TARGET_DIRECTORY }}
+        run: powershell -version 5.1 -command "./UseUnoWinUI.ps1 3" -ErrorAction Stop
+        if: ${{ matrix.platform == 'WinUI3' }}
+
+      - name: MSBuild
+        run: msbuild.exe CommunityToolkit.AllComponents.sln /restore /nowarn:MSB4011 -p:Configuration=Release -m -p:UseDotNetNativeToolchain=false
+
+      # Build All Packages
+      - name: pack experiments
+        working-directory: ./tooling/Scripts/
+        run: ./PackEachExperiment.ps1 all
+
+      # Run tests
+      - name: Setup VSTest Path
+        uses: darenm/Setup-VSTest@v1
+
+      - name: Install Testspace Module
+        uses: testspace-com/setup-testspace@v1
+        with:
+          domain: ${{ github.repository_owner }}
+
+      - name: Run SourceGenerators tests
+        id: test-generator
+        run: vstest.console.exe ./tooling/CommunityToolkit.Tooling.SampleGen.Tests/bin/Release/net6.0/CommunityToolkit.Tooling.SampleGen.Tests.dll /logger:"trx;LogFileName=SourceGenerators.trx"
+
+      - name: Run experiment tests against ${{ env.TEST_PLATFORM }}
+        id: test-platform
+        run:  vstest.console.exe ./tooling/**/CommunityToolkit.Tests.${{ env.TEST_PLATFORM }}.build.appxrecipe /Framework:FrameworkUap10 /logger:"trx;LogFileName=${{ env.TEST_PLATFORM }}.trx"
+
+      - name: Create test reports
+        run: |
+          testspace '[${{ matrix.platform }}]./TestResults/*.trx'
+        if: ${{ always() && (steps.test-generator.conclusion == 'success' || steps.test-platform.conclusion == 'success') }}
+
+      - name: Artifact - Diagnostic Logs
+        uses: actions/upload-artifact@v3
+        if: ${{ (env.ENABLE_DIAGNOSTICS == 'true' || env.COREHOST_TRACE != '') && always() }}
+        with:
+          name: build-logs
+          path: ./**/*.*log
+
+      - name: Windows System Error Log
+        shell: pwsh
+        working-directory: ./
+        run: Get-EventLog -LogName System -EntryType Error | Format-List