diff --git a/.gitignore b/.gitignore
index 0a4f2519c8..8834240e88 100644
--- a/.gitignore
+++ b/.gitignore
@@ -279,3 +279,4 @@ testing-smoke/
 # UpdateDependenciesAndSubmitPullRequest: if no upgrades are performed, the
 # sanity check fails when "git status" shows this file.
 msbuild.ProjectImports.zip
+Build_*.ProjectImports.zip
diff --git a/Directory.Build.props b/Directory.Build.props
index 99d2e570e5..8247c3ee01 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -202,10 +202,13 @@
     <RootRepo>known-good</RootRepo>
     <RootRepoTests>known-good-tests</RootRepoTests>
   </PropertyGroup>
-
-  <ItemGroup>
-    <SourceBuiltPackage Include="$(SourceBuiltPackagesPath)/*.nupkg" />
-  </ItemGroup>
+  
+  <!--
+    Semaphore path for incremental builds
+  -->
+  <PropertyGroup>
+    <CompletedSemaphorePath>$(BaseIntermediatePath)semaphores/</CompletedSemaphorePath>
+  </PropertyGroup>
 
   <!-- CLI internal version is statically set by us to a version that will never show up in the wild.
        This ensures we will never restore a public version instead of our source-built version.  We
diff --git a/Directory.Build.targets b/Directory.Build.targets
index f477ded43c..e875359090 100644
--- a/Directory.Build.targets
+++ b/Directory.Build.targets
@@ -13,10 +13,14 @@
   <Target Name="AcquireDarc"
           Condition="
             '$(OfflineBuild)' != 'true' and
-            '$(SkipAcquireDarc)' != 'true'">
+            '$(SkipAcquireDarc)' != 'true'"
+          Inputs="$(MSBuildThisFileDirectory)tools-local\acquire-darc\acquire-darc.proj"
+          Outputs="$(CompletedSemaphorePath)AcquireDarc.complete">
     <MSBuild
       Projects="$(MSBuildThisFileDirectory)tools-local\acquire-darc\acquire-darc.proj"
       Targets="AcquireDarcCore" />
+
+    <WriteLinesToFile File="$(CompletedSemaphorePath)AcquireDarc.complete" Overwrite="true" />
   </Target>
 
   <Target Name="GetCommonDarcCloneCommand" DependsOnTargets="AcquireDarc">
diff --git a/build-source-tarball.sh b/build-source-tarball.sh
index d8a15b0391..1aa2f8e26b 100755
--- a/build-source-tarball.sh
+++ b/build-source-tarball.sh
@@ -143,6 +143,6 @@ mkdir -p "$FULL_TARBALL_ROOT"
 MAIN_BUILD_ARGS+=( "/p:TarballRoot=$FULL_TARBALL_ROOT" )
 MAIN_BUILD_ARGS+=( "/p:PackSourceBuildTarball=true" )
 
-$SCRIPT_ROOT/build.sh ${MAIN_BUILD_ARGS[@]} "$@"
+$SCRIPT_ROOT/build.sh ${MAIN_BUILD_ARGS[@]} /bl:$SCRIPT_ROOT/artifacts/log/Debug/BuildTarball_$(date +"%m%d%H%M%S").binlog "$@"
 
 echo "Done. Tarball created: $TARBALL_ROOT"
diff --git a/build.proj b/build.proj
index ce49bd5715..86172a5804 100644
--- a/build.proj
+++ b/build.proj
@@ -67,7 +67,9 @@
   -->
   <Target Name="CopyAndDisassembleReferenceOnlyPackages"
           AfterTargets="Build"
-          Condition="'$(OfflineBuild)' != 'true' and '$(ArchiveDownloadedPackages)' == 'true' and '$(OS)' != 'Windows_NT'">
+          Condition="'$(OfflineBuild)' != 'true' and '$(ArchiveDownloadedPackages)' == 'true' and '$(OS)' != 'Windows_NT'"
+          Inputs="$(MSBuildProjectFullPath)" 
+          Outputs="$(CompletedSemaphorePath)CopyAndDisassembleReferenceOnlyPackages.complete" >
 
     <CopyReferenceOnlyPackages
         PackageCacheDir="$(PackagesDir)"
@@ -124,6 +126,8 @@
     <ReplaceTextInFile InputFile="%(RefAssyNuspecFiles.Identity)"
         OldText="http://go.microsoft.com/fwlink/?LinkId=529443"
         NewText="https://microsoft.mit-license.org/" />
+        
+    <WriteLinesToFile File="$(CompletedSemaphorePath)CopyAndDisassembleReferenceOnlyPackages.complete" Overwrite="true" />
   </Target>
 
   <Target Name="ReplaceLicenseFiles"
@@ -148,7 +152,9 @@
 
   <Target Name="DownloadSourceBuildReferencePackages"
           AfterTargets="Build"
-          Condition="'$(OfflineBuild)' != 'true' and '$(OS)' != 'Windows_NT' and '$(SkipDownloadingReferencePackages)' != 'true'">
+          Condition="'$(OfflineBuild)' != 'true' and '$(OS)' != 'Windows_NT' and '$(SkipDownloadingReferencePackages)' != 'true'"
+          Inputs="$(MSBuildProjectFullPath)" 
+          Outputs="$(CompletedSemaphorePath)DownloadSourceBuildReferencePackages.complete" >
     <PropertyGroup Condition="'$(DownloadSourceBuildReferencePackagesTimeoutSeconds)' == ''">
       <DownloadSourceBuildReferencePackagesTimeoutSeconds>600</DownloadSourceBuildReferencePackagesTimeoutSeconds>
     </PropertyGroup>
@@ -157,11 +163,15 @@
           SourceUrl="$(ReferencePackagesTarballUrl)$(ReferencePackagesTarballName).$(PrivateSourceBuildReferencePackagesPackageVersion).tar.gz"
           DestinationFolder="$(ExternalTarballsDir)"
           TimeoutSeconds="$(DownloadSourceBuildReferencePackagesTimeoutSeconds)" />
+          
+    <WriteLinesToFile File="$(CompletedSemaphorePath)DownloadSourceBuildReferencePackages.complete" Overwrite="true" />
   </Target>
 
   <Target Name="DownloadSourceBuiltArtifacts"
           AfterTargets="Build"
-          Condition="'$(OfflineBuild)' != 'true' and '$(OS)' != 'Windows_NT' and '$(SkipDownloadingPreviouslySourceBuiltPackages)' != 'true'">
+          Condition="'$(OfflineBuild)' != 'true' and '$(OS)' != 'Windows_NT' and '$(SkipDownloadingPreviouslySourceBuiltPackages)' != 'true'"
+          Inputs="$(MSBuildProjectFullPath)" 
+          Outputs="$(CompletedSemaphorePath)DownloadSourceBuiltArtifacts.complete" >
     <PropertyGroup Condition="'$(DownloadSourceBuiltArtifactsTimeoutSeconds)' == ''">
       <DownloadSourceBuiltArtifactsTimeoutSeconds>1500</DownloadSourceBuiltArtifactsTimeoutSeconds>
     </PropertyGroup>
@@ -170,6 +180,8 @@
           SourceUrl="$(SourceBuiltArtifactsTarballUrl)$(SourceBuiltArtifactsTarballName).$(PrivateSourceBuiltArtifactsPackageVersion).tar.gz"
           DestinationFolder="$(ExternalTarballsDir)"
           TimeoutSeconds="$(DownloadSourceBuiltArtifactsTimeoutSeconds)" />
+          
+    <WriteLinesToFile File="$(CompletedSemaphorePath)DownloadSourceBuiltArtifacts.complete" Overwrite="true" />
   </Target>
 
   <!-- After building, generate a prebuilt usage report. -->
@@ -191,7 +203,9 @@
 
   <Target Name="ReportPoisonUsage"
           AfterTargets="Build"
-          Condition="'$(EnablePoison)' == 'true' and '$(OfflineBuild)' == 'true'">
+          Condition="'$(EnablePoison)' == 'true' and '$(OfflineBuild)' == 'true'"
+          Inputs="$(MSBuildProjectFullPath)" 
+          Outputs="$(CompletedSemaphorePath)ReportPoisonUsage.complete" >
     <ItemGroup>
       <FinalCliTarball Include="$(SourceBuiltTarBallPath)**/*$(TarBallExtension)" />
     </ItemGroup>
@@ -199,15 +213,21 @@
                     HashCatalogFilePath="$(PoisonReportDataFile)"
                     MarkerFileName="$(PoisonMarkerFile)"
                     PoisonReportOutputFilePath="$(PoisonUsageReportFile)" />
+          
+    <WriteLinesToFile File="$(CompletedSemaphorePath)ReportPoisonUsage.complete" Overwrite="true" />
   </Target>
 
-  <Target Name="GeneratePrebuiltBurndownData">
+  <Target Name="GeneratePrebuiltBurndownData"
+          Inputs="$(MSBuildProjectFullPath)" 
+          Outputs="$(CompletedSemaphorePath)GeneratePrebuiltBurndownData.complete" >
     <WriteUsageBurndownData RootDirectory="$(ProjectDir)"
                             PrebuiltBaselineFile="$(OnlineBaselineDataFile)"
                             OutputFilePath="$(OnlinePrebuiltBurndownDataFile)" />
     <WriteUsageBurndownData RootDirectory="$(ProjectDir)"
                             PrebuiltBaselineFile="$(OfflineBaselineDataFile)"
                             OutputFilePath="$(OfflinePrebuiltBurndownDataFile)" />
+          
+    <WriteLinesToFile File="$(CompletedSemaphorePath)GeneratePrebuiltBurndownData.complete" Overwrite="true" />
   </Target>
 
   <Target Name="RunSmokeTest" DependsOnTargets="GetProdConBlobFeedUrl">
diff --git a/build.sh b/build.sh
index 640f6163ad..923aa5aba3 100755
--- a/build.sh
+++ b/build.sh
@@ -134,5 +134,5 @@ scriptroot="$( cd -P "$( dirname "$source" )" && pwd )"
 if [ "$alternateTarget" == "true" ]; then
   "$CLIPATH/dotnet" $SDKPATH/MSBuild.dll "$scriptroot/build.proj" /bl:source-build-test.binlog /flp:v=diag /clp:v=m "$@"
 else
-  "$scriptroot/eng/common/build.sh" --restore --build -c Release --warnaserror false -bl /flp:v=diag "$@"
+  "$scriptroot/eng/common/build.sh" --restore --build -c Release --warnaserror false /bl:$scriptroot/artifacts/log/Debug/Build_$(date +"%m%d%H%M%S").binlog /flp:v=diag "$@"
 fi
diff --git a/repos/Directory.Build.props b/repos/Directory.Build.props
index 280ac79f19..0244f3e19d 100644
--- a/repos/Directory.Build.props
+++ b/repos/Directory.Build.props
@@ -32,6 +32,11 @@
     <RepoConsoleLogFile>$(LoggingDir)$(RepositoryName).log</RepoConsoleLogFile>
     <RedirectRepoOutputToLog Condition="'$(MinimalConsoleLogOutput)' == 'true'">&gt;&gt; $(RepoConsoleLogFile) 2&gt;&amp;1</RedirectRepoOutputToLog>
     <IsStable Condition="'$(UseStableVersions)' == 'true'">true</IsStable>
+
+    <!--
+      Repo specific semaphore path for incremental build
+    -->
+    <RepoCompletedSemaphorePath>$(CompletedSemaphorePath)$(RepositoryName)/</RepoCompletedSemaphorePath>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(OS)' == 'Windows_NT'">
diff --git a/repos/Directory.Build.targets b/repos/Directory.Build.targets
index a2b8ba0c55..1538866d00 100644
--- a/repos/Directory.Build.targets
+++ b/repos/Directory.Build.targets
@@ -66,10 +66,14 @@
     <MSBuild Projects="@(_DependentProject)" Targets="Build" BuildInParallel="$(BuildInParallel)" StopOnFirstFailure="true" />
   </Target>
 
-  <Target Name="ApplyPatches" Condition="Exists('$(PatchesDir)$(RepositoryName)') and '$(SkipPatches)' != 'true'">
-    <ItemGroup>
-      <PatchesToApply Include="$(PatchesDir)$(RepositoryName)/*.patch" />
-    </ItemGroup>
+  <ItemGroup  Condition="Exists('$(PatchesDir)$(RepositoryName)')" >
+    <PatchesToApply Include="$(PatchesDir)$(RepositoryName)/*.patch" />
+  </ItemGroup>
+
+  <Target Name="ApplyPatches" 
+          Condition="'@(PatchesToApply)' != '' and '$(SkipPatches)' != 'true'"
+          Inputs="@(PatchesToApply)"
+          Outputs="$(RepoCompletedSemaphorePath)ApplyPatches.complete" >
 
     <PropertyGroup>
       <PatchCommand>git --work-tree=$(ProjectDirectory) apply --ignore-whitespace --whitespace=nowarn</PatchCommand>
@@ -78,11 +82,15 @@
     <Exec Command="$(PatchCommand) %(PatchesToApply.Identity)"
           WorkingDirectory="$(ProjectDirectory)"
           Condition="'@(PatchesToApply)' != ''" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)ApplyPatches.complete" Overwrite="true" />
   </Target>
 
   <Target Name="UpdateNuGetConfig"
           BeforeTargets="Build"
-          Condition="'$(NuGetConfigFile)' != '' OR '@(NuGetConfigFiles)' != ''">
+          Condition="'$(NuGetConfigFile)' != '' OR '@(NuGetConfigFiles)' != ''"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)UpdateNuGetConfig.complete">
     <!-- Update the detected or manually specified NuGetConfigFile, but also allow multiple. -->
     <ItemGroup>
       <NuGetConfigFiles Include="$(NuGetConfigFile)" />
@@ -123,11 +131,15 @@
       NuGetConfigFile="%(NuGetConfigFiles.Identity)"
       SourceName="dotnet3.1-internal-transport"
       SourcePath="https://pkgs.dev.azure.com/dnceng/_packaging/dotnet3.1-internal-transport/nuget/v3/index.json" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)UpdateNuGetConfig.complete" Overwrite="true" />
   </Target>
 
   <Target Name="UpdateGlobalJsonVersions"
           BeforeTargets="Build"
-          Condition="'$(GlobalJsonFile)' != ''">
+          Condition="'$(GlobalJsonFile)' != ''"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)UpdateGlobalJsonVersions.complete">
     <ItemGroup>
       <_PossibleCliVersionJsonPath Include="sdk.version" />
       <_PossibleCliVersionJsonPath Include="tools.dotnet" />
@@ -137,10 +149,14 @@
                 PathToAttribute="%(_PossibleCliVersionJsonPath.Identity)"
                 NewAttributeValue="$(SDK_VERSION)"
                 SkipUpdateIfMissingKey="true" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)UpdateGlobalJsonVersions.complete" Overwrite="true" />
   </Target>
 
   <Target Name="CreateBuildOutputProps"
-          BeforeTargets="Build">
+          BeforeTargets="Build"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)CreateBuildOutputProps.complete">
     <PropertyGroup>
       <_PackageVersionPropsBackupPath>$(PackageVersionPropsPath).pre.$(RepositoryName).xml</_PackageVersionPropsBackupPath>
     </PropertyGroup>
@@ -178,12 +194,15 @@
       <Output TaskParameter="ConflictingPackageInfos" ItemName="ConflictingPackageInfos" />
     </GetSourceBuiltNupkgCacheConflicts>
 
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)CreateBuildOutputProps.complete" Overwrite="true" />
   </Target>
 
   <Target Name="CheckSourceBuiltNupkgConflictUsages"
           DependsOnTargets="GetAllProjectDirectories"
           AfterTargets="CreateBuildOutputProps"
-          Condition="'@(ConflictingPackageInfos)' != ''">
+          Condition="'@(ConflictingPackageInfos)' != ''"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)CheckSourceBuiltNupkgConflictUsages.complete">
     <PropertyGroup>
       <_ReportDir>$(ConflictingPackageReportDir)before-$(RepositoryName)/</_ReportDir>
       <_ReportDataFile>$(_ReportDir)usage.xml</_ReportDataFile>
@@ -200,10 +219,14 @@
 
     <Warning Text="Detected packages in the cache that should be source-built, but contents don't match. See $(_ReportDir) for usage details:" />
     <Warning Text="%(ConflictingPackageInfos.PackageId)/%(ConflictingPackageInfos.PackageVersion) : %(ConflictingPackageInfos.WarningMessage)" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)CheckSourceBuiltNupkgConflictUsages.complete" Overwrite="true" />
   </Target>
 
   <Target Name="CreateCombinedRestoreSourceAndVersionProps"
-          BeforeTargets="Build">
+          BeforeTargets="Build"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)CreateCombinedRestoreSourceAndVersionProps.complete">
     <ItemGroup>
       <_DotNetRestoreSources Include="$(SourceBuiltPackagesPath)" />
       <_DotNetRestoreSources Include="$(ReferencePackagesDir)" Condition="'$(OfflineBuild)' == 'true'"/>
@@ -218,6 +241,8 @@
                                        AdditionalAssetDirs="@(_AdditionalAssetDirs)"
                                        RestoreSources="@(_DotNetRestoreSources)"
                                        OutputPath="$(RestoreSourcePropsPath)" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)CreateCombinedRestoreSourceAndVersionProps.complete" Overwrite="true" />
   </Target>
 
   <!--
@@ -226,7 +251,9 @@
     directories and causing differences vs. ordinary build).
   -->
   <Target Name="PreventDirectoryBuildPropsTargetsEscape"
-          BeforeTargets="Build">
+          BeforeTargets="Build"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)PreventDirectoryBuildPropsTargetsEscape.complete">
     <ItemGroup>
       <DirectoryBuildFilename Include="Directory.Build.targets" />
       <DirectoryBuildFilename Include="Directory.Build.props" />
@@ -236,9 +263,14 @@
       Lines="&lt;Project /&gt;"
       File="$([MSBuild]::NormalizePath('$(ClonedSubmoduleDirectory)', '%(DirectoryBuildFilename.Identity)'))"
       Overwrite="True" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)PreventDirectoryBuildPropsTargetsEscape.complete" Overwrite="true" />
   </Target>
 
-  <Target Name="Build" DependsOnTargets="BuildRepoReferences">
+  <Target Name="Build" 
+          DependsOnTargets="BuildRepoReferences"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)Build.complete">
     <Message Importance="High" Text="[$([System.DateTime]::Now.ToString('HH:mm:ss.ff'))] Building $(ProjectBuildReason)" />
     <Message Importance="High" Text="Running command:" />
     <Message Importance="High" Text="  $(BuildCommand) $(RepoApiArgs)" Condition="'$(BuildCommand)' != ''" />
@@ -248,6 +280,8 @@
     <Message Importance="High" Text="    %(EnvironmentVariables.Identity)" />
     <CallTarget Targets="RepoBuild" />
     <Message Importance="High" Text="[$([System.DateTime]::Now.ToString('HH:mm:ss.ff'))] Building $(ProjectBuildReason)...done" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)Build.complete" Overwrite="true" />
     <OnError ExecuteTargets="ReportRepoError" />
   </Target>
 
@@ -271,7 +305,10 @@
     <Message Importance="High" Text="See '$(RepoConsoleLogFile)' for more information." Condition="Exists('$(RepoConsoleLogFile)')" />
   </Target>
 
-  <Target Name="Package" AfterTargets="Build" Condition="'$(BuildPackagesCommand)' != ''">
+  <Target Name="Package" AfterTargets="Build" 
+          Condition="'$(BuildPackagesCommand)' != ''"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)Package.complete">
     <Message Importance="High" Text="[$([System.DateTime]::Now.ToString('HH:mm:ss.ff'))] Packaging $(ProjectBuildReason)" />
     <Message Importance="High" Text="Running command:" />
     <Message Importance="High" Text="  $(BuildPackagesCommand)" />
@@ -283,6 +320,8 @@
           EnvironmentVariables="@(EnvironmentVariables)"
           IgnoreStandardErrorWarningFormat="true" />
     <Message Importance="High" Text="[$([System.DateTime]::Now.ToString('HH:mm:ss.ff'))] Packaging $(ProjectBuildReason)...done" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)Package.complete" Overwrite="true" />
     <OnError ExecuteTargets="ReportRepoError" />
   </Target>
 
@@ -297,16 +336,22 @@
   <Target Name="CopyPackage"
           AfterTargets="Package"
           Condition="'$(OutputPlacementRepoApiImplemented)' != 'true' AND ('$(PackagesOutput)' != '' OR '@(PackagesOutputList)' != '')"
-          DependsOnTargets="GatherBuiltPackages">
+          DependsOnTargets="GatherBuiltPackages"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)CopyPackage.complete">
     <Copy SourceFiles="@(_BuiltPackages)"
           DestinationFolder="$(SourceBuiltPackagesPath)"
           Condition="'@(_BuiltPackages)'!=''" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)CopyPackage.complete" Overwrite="true" />
   </Target>
 
   <Target Name="RemoveBuiltPackagesFromCache"
           AfterTargets="Package"
           Condition="'@(_BuiltPackages)'!=''"
-          DependsOnTargets="GatherBuiltPackages">
+          DependsOnTargets="GatherBuiltPackages"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)RemoveBuiltPackagesFromCache.complete">
 
     <ReadNuGetPackageInfos PackagePaths="@(_BuiltPackages)">
       <Output TaskParameter="PackageInfoItems" ItemName="_BuiltPackageInfos" />
@@ -321,12 +366,16 @@
     </ItemGroup>
     <Copy SourceFiles="@(_FilesToCopy)" DestinationFolder="$(PreviouslyRestoredPackagesPath)$(RepositoryName)/" />
     <Delete Files="@(_FilesToDelete)" />
+          
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)RemoveBuiltPackagesFromCache.complete" Overwrite="true" />
   </Target>
 
   <Target Name="ExtractToolPackage"
           DependsOnTargets="GatherBuiltPackages"
           AfterTargets="Build"
-          Condition="'@(BuiltSdkPackageOverride)' != ''">
+          Condition="'@(BuiltSdkPackageOverride)' != ''"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)ExtractToolPackage.complete">
     <ItemGroup>
       <_ToolPackage
         Condition="'%(BuiltSdkPackageOverride.Version)' == ''"
@@ -348,11 +397,15 @@
     </ItemGroup>
 
     <Copy SourceFiles="@(ExtractedToolFiles)" DestinationFolder="$(ToolPackageExtractDir)/" />
+          
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)ExtractToolPackage.complete" Overwrite="true" />
   </Target>
 
   <Target Name="EnsurePackagesCreated"
           AfterTargets="CopyPackage"
-          Condition="'$(SkipEnsurePackagesCreated)' != 'true'">
+          Condition="'$(SkipEnsurePackagesCreated)' != 'true'"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)EnsurePackagesCreated.complete">
     <ItemGroup>
       <JustSourceBuiltPackages
         Include="$(SourceBuiltPackagesPath)*.nupkg"
@@ -377,6 +430,8 @@
 
     <Message Importance="High" Text="New NuGet package(s) after building $(RepositoryName):" />
     <Message Importance="High" Text="  -> %(_JustSourceBuiltPackageInfos.PackageId) %(_JustSourceBuiltPackageInfos.PackageVersion)" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)EnsurePackagesCreated.complete" Overwrite="true" />
   </Target>
 
   <Target Name="Clean" Condition="'$(CleanCommand)' != ''" >
@@ -410,7 +465,9 @@
   </Target>
 
   <Target Name="WritePrebuiltUsageData"
-          DependsOnTargets="GetAllProjectDirectories">
+          DependsOnTargets="GetAllProjectDirectories"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)WritePrebuiltUsageData.complete">
     <!-- Save the PVP snapshot of each build step to be evaluated while building the report. -->
     <ItemGroup>
       <PackageVersionPropsSnapshotFiles Include="$(IntermediatePath)PackageVersions.props.pre.*.xml" />
@@ -456,7 +513,9 @@
       IgnoredProjectAssetsJsonFiles="@(IgnoredProjectAssetsJsonFiles)"
       DataFile="$(PackageReportDataFile)"
       ProjectAssetsJsonArchiveFile="$(ProjectAssetsJsonArchiveFile)" />
-  </Target>
+      
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)WritePrebuiltUsageData.complete" Overwrite="true" />
+</Target>
 
   <Target Name="GetAllProjectDirectories">
     <ItemGroup>
@@ -471,7 +530,9 @@
     </MSBuild>
   </Target>
 
-  <Target Name="ReportPrebuiltUsage">
+  <Target Name="ReportPrebuiltUsage"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)ReportPrebuiltUsage.complete">
     <PropertyGroup>
       <FailOnPrebuiltBaselineError Condition="'$(FailOnPrebuiltBaselineError)' == ''">false</FailOnPrebuiltBaselineError>
     </PropertyGroup>
@@ -498,6 +559,8 @@
       OutputReportFile="$(PackageReportDir)baseline-comparison.xml"
       AllowTestProjectUsage="$(AllowTestProjectUsage)"
       ContinueOnError="$(ContinueOnPrebuiltBaselineError)" />
+      
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)ReportPrebuiltUsage.complete" Overwrite="true" />
   </Target>
 
   <Target Name="GetProjectDirectory" Outputs="$(ProjectDirectory)" />
diff --git a/repos/aspnetcore.proj b/repos/aspnetcore.proj
index 56a7d52c93..b4bd5e9e3e 100644
--- a/repos/aspnetcore.proj
+++ b/repos/aspnetcore.proj
@@ -71,7 +71,10 @@
 
   <UsingTask AssemblyFile="$(XPlatSourceBuildTasksAssembly)" TaskName="PublishToolsetBinaries" />
 
-  <Target Name="PublishBinaries" AfterTargets="Build">
+  <Target Name="PublishBinaries" 
+          AfterTargets="Build"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)PublishBinaries.complete">
     <ItemGroup>
       <AspNetTarballs Include="$(TarballOutputDir)aspnetcore-*.tar.gz" />
       <ExtraAspNetFiles Include="$(TarballOutputDir)*.version" />
@@ -84,6 +87,8 @@
     <Message Text="Published ASP.NET runtime version $(PublishedVersion)" Importance="High" />
     <Copy SourceFiles="@(ExtraAspNetFiles)" DestinationFolder="$(SourceBuiltAspNetCoreRuntime)$(PublishedVersion)" Condition="'@(ExtraAspNetFiles)' != ''" />
     <Message Text="Published extra ASP.NET files @(ExtraAspNetFiles) to $(SourceBuiltAspNetCoreRuntime)$(PublishedVersion)" Importance="High" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)PublishBinaries.complete" Overwrite="true" />
   </Target>
 
   <Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk" />
diff --git a/repos/core-sdk.proj b/repos/core-sdk.proj
index 3cc8a5f9d9..f7b426177c 100644
--- a/repos/core-sdk.proj
+++ b/repos/core-sdk.proj
@@ -98,7 +98,10 @@
     <EnvironmentVariables Include="CLIBUILD_SKIP_BUNDLEDDOTNETTOOLS=true" />
   </ItemGroup>
 
-  <Target Name="CopyTarBall" AfterTargets="CopyPackage">
+  <Target Name="CopyTarBall" 
+          AfterTargets="CopyPackage"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)CopyTarBall.complete">
     <ItemGroup>
       <CliTarBalls Include="$(TarBallOutput)*$(TarBallExtension)" />
     </ItemGroup>
@@ -106,6 +109,8 @@
     <Copy SourceFiles="@(CliTarBalls)"
           DestinationFolder="$(SourceBuiltTarBallPath)"
           Condition="'@(CliTarBalls)'!=''" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)CopyTarBall.complete" Overwrite="true" />
   </Target>
 
   <Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk" />
diff --git a/repos/core-setup.common.targets b/repos/core-setup.common.targets
index 6c0ef2c68c..81c6ecebd5 100644
--- a/repos/core-setup.common.targets
+++ b/repos/core-setup.common.targets
@@ -5,7 +5,10 @@
   <UsingTask AssemblyFile="$(XPlatSourceBuildTasksAssembly)" TaskName="PublishCoreSetupBinaries" />
 
   <!-- Need to "publish" the tarballs for cli, until cli respects the assets blob -->
-  <Target Name="PublishBinaries" AfterTargets="Package">
+  <Target Name="PublishBinaries" 
+          AfterTargets="Package"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)PublishBinaries.complete">
     <ItemGroup>
       <CoreSetupTarballs Include="$(SourceBuiltAssetsDir)dotnet-runtime-*$(TarBallExtension)" />
       <CoreSetupTarballs Include="$(SourceBuiltAssetsDir)dotnet-hostfxr-*$(TarBallExtension)" />
@@ -15,9 +18,14 @@
       <Output TaskParameter="PublishedVersion" PropertyName="PublishedVersion" />
     </PublishCoreSetupBinaries>
     <Message Text="Published core-setup binaries version $(PublishedVersion)" Importance="High" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)PublishBinaries.complete" Overwrite="true" />
   </Target>
 
-  <Target Name="CopyBinariesToBinFolder" AfterTargets="PublishBinaries">
+  <Target Name="CopyBinariesToBinFolder" 
+          AfterTargets="PublishBinaries"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)CopyBinariesToBinFolder.complete">
     <ItemGroup>
       <_builtRuntimePackages Include="$(SourceBuiltAssetsDir)*.symbols.nupkg" />
       <_builtRuntimePackages>
@@ -30,6 +38,8 @@
     <Copy SourceFiles="@(BinariesToCopy)"
           DestinationFolder="$(OutputPath)runtime"
           Condition="'@(BinariesToCopy)'!=''" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)CopyBinariesToBinFolder.complete" Overwrite="true" />
   </Target>
 
   <Target Name="SetOutputList" AfterTargets="RepoBuild">
diff --git a/repos/coreclr-portable.proj b/repos/coreclr-portable.proj
index 3973f21ebc..378547eae6 100644
--- a/repos/coreclr-portable.proj
+++ b/repos/coreclr-portable.proj
@@ -15,7 +15,9 @@
   </ItemGroup>
 
   <Target Name="CopyTools"
-          AfterTargets="Package">
+          AfterTargets="Package"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)CopyTools.complete">
     <PropertyGroup>
       <CoreClrDestinationDir>$(ToolPackageExtractDir)coreclr-tools</CoreClrDestinationDir>
       <AssemblyExtension Condition="'$(TargetOS)' == 'Linux'">so</AssemblyExtension>
@@ -34,6 +36,8 @@
     <Message Importance="High" Text="Copying source-built ILAsm and ILDasm '@(CoreClrTools)' to '$(CoreClrDestinationDir)'" />
 
     <Copy SourceFiles="@(CoreClrTools)" DestinationFolder="$(CoreClrDestinationDir)" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)CopyTools.complete" Overwrite="true" />
   </Target>
 
   <Target Name="CleanupRepoForNonPortableBuild" AfterTargets="RemoveBuiltPackagesFromCache">
diff --git a/repos/linker.proj b/repos/linker.proj
index 9390d1e234..5ea5c5a341 100644
--- a/repos/linker.proj
+++ b/repos/linker.proj
@@ -33,7 +33,9 @@
 
   <!-- Extract this package into packages dir, because repos assume it's restored as a tool. -->
   <Target Name="ExtractLinkerPackageToCache"
-          AfterTargets="Package">
+          AfterTargets="Package"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)ExtractLinkerPackageToCache.complete">
     <PropertyGroup>
       <ILLinkTasksPackageFile>$(PackagesOutput)/$(ILLinkTasksPackageId).$(OutputPackageVersion).nupkg</ILLinkTasksPackageFile>
       <ILLinkTasksPackageIdToLower>$(ILLinkTasksPackageId.ToLowerInvariant())</ILLinkTasksPackageIdToLower>
@@ -44,7 +46,9 @@
     <ZipFileExtractToDirectory SourceArchive="$(ILLinkTasksPackageFile)"
                                DestinationDirectory="$(PackagesDir)$(ILLinkTasksPackageIdToLower)/$(OutputPackageVersion)/"
                                OverwriteDestination="true" />
-  </Target>
+ 
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)ExtractLinkerPackageToCache.complete" Overwrite="true" />
+ </Target>
 
   <!-- Replace file includes in nuspec as recommended in the linker repo's ./corebuild/README.md -->
   <Target Name="ReplaceNuspecDllIncludeLines" BeforeTargets="Build" Condition="'$(TargetOS)' != 'Windows_NT'">
diff --git a/repos/msbuild.proj b/repos/msbuild.proj
index b9443f9a65..4fdcc909ca 100644
--- a/repos/msbuild.proj
+++ b/repos/msbuild.proj
@@ -81,7 +81,9 @@
 
   <Target Name="ExtractCentralPackageVersionsSdkPackage"
           BeforeTargets="SetSourceBuiltSdkOverrides"
-          Condition="'$(OfflineBuild)' == 'true'">
+          Condition="'$(OfflineBuild)' == 'true'"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)ExtractCentralPackageVersionsSdkPackage.complete">
     <ItemGroup>
       <_CentralVersionsToolPackage
         Include="$(ReferencePackagesDir)%(CentralPackageVersionsSdkOverride.Identity)*.nupkg"
@@ -98,6 +100,8 @@
       SourceArchive="@(_CentralVersionsToolPackage)"
       DestinationDirectory="$(CentralVersionsSdkDir)"
       OverwriteDestination="true" />
+ 
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)ExtractCentralPackageVersionsSdkPackage.complete" Overwrite="true" />
   </Target>
   <!--
     End workaround: https://github.com/dotnet/source-build/issues/933
diff --git a/repos/toolset.proj b/repos/toolset.proj
index 8434f2f8e4..548c0765c4 100644
--- a/repos/toolset.proj
+++ b/repos/toolset.proj
@@ -67,7 +67,10 @@
   <UsingTask AssemblyFile="$(XPlatSourceBuildTasksAssembly)" TaskName="PublishToolsetBinaries" />
 
   <!-- Need to "publish" the tarballs for cli, until cli respects the assets blob -->
-  <Target Name="PublishBinaries" AfterTargets="Build">
+  <Target Name="PublishBinaries" 
+          AfterTargets="Build"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(RepoCompletedSemaphorePath)PublishBinaries.complete">
     <ItemGroup>
       <ToolsetZips Include="$(ToolsetZipOutputDir)dotnet-*.zip" />
     </ItemGroup>
@@ -77,6 +80,8 @@
       <Output TaskParameter="PublishedVersion" PropertyName="PublishedVersion" />
     </PublishToolsetBinaries>
     <Message Text="Published toolset binaries version $(PublishedVersion)" Importance="High" />
+
+    <WriteLinesToFile File="$(RepoCompletedSemaphorePath)PublishBinaries.complete" Overwrite="true" />
   </Target>
 
   <Import Project="Sdk.targets" Sdk="Microsoft.NET.Sdk" />
diff --git a/support/tarball/build.sh b/support/tarball/build.sh
index 886b868470..60b6bedf07 100755
--- a/support/tarball/build.sh
+++ b/support/tarball/build.sh
@@ -142,10 +142,11 @@ export DOTNET_CLI_TELEMETRY_OPTOUT=1
 export DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1
 export NUGET_PACKAGES=$restoredPackagesDir/
 
-$CLI_ROOT/dotnet $CLI_ROOT/sdk/$SDK_VERSION/MSBuild.dll /bl:BuildXPlatTasks.binlog $SCRIPT_ROOT/tools-local/init-build.proj /t:PrepareOfflineLocalTools ${MSBUILD_ARGUMENTS[@]} "$@"
+LogDateStamp=$(date +"%m%d%H%M%S")
+$CLI_ROOT/dotnet $CLI_ROOT/sdk/$SDK_VERSION/MSBuild.dll /bl:$SCRIPT_ROOT/artifacts/log/Debug/BuildXPlatTasks_$LogDateStamp.binlog $SCRIPT_ROOT/tools-local/init-build.proj /t:PrepareOfflineLocalTools ${MSBUILD_ARGUMENTS[@]} "$@"
 
 echo "Rebuild reference assemblies"
-$CLI_ROOT/dotnet $CLI_ROOT/sdk/$SDK_VERSION/MSBuild.dll /bl:initBuildReferenceAssemblies.binlog $SCRIPT_ROOT/tools-local/init-build.proj /t:BuildReferenceAssemblies ${MSBUILD_ARGUMENTS[@]} "$@"
+$CLI_ROOT/dotnet $CLI_ROOT/sdk/$SDK_VERSION/MSBuild.dll /bl:$SCRIPT_ROOT/artifacts/log/Debug/initBuildReferenceAssemblies_$LogDateStamp.binlog $SCRIPT_ROOT/tools-local/init-build.proj /t:BuildReferenceAssemblies ${MSBUILD_ARGUMENTS[@]} "$@"
 
-$CLI_ROOT/dotnet $CLI_ROOT/sdk/$SDK_VERSION/MSBuild.dll /bl:initWriteDynamicPropsToStaticPropsFiles.binlog $SCRIPT_ROOT/tools-local/init-build.proj /t:WriteDynamicPropsToStaticPropsFiles /p:GeneratingStaticPropertiesFile=true ${MSBUILD_ARGUMENTS[@]} "$@"
-$CLI_ROOT/dotnet $CLI_ROOT/sdk/$SDK_VERSION/MSBuild.dll /bl:build.binlog $SCRIPT_ROOT/build.proj ${MSBUILD_ARGUMENTS[@]} "$@"
+$CLI_ROOT/dotnet $CLI_ROOT/sdk/$SDK_VERSION/MSBuild.dll /bl:$SCRIPT_ROOT/artifacts/log/Debug/initWriteDynamicPropsToStaticPropsFiles_$LogDateStamp.binlog $SCRIPT_ROOT/tools-local/init-build.proj /t:WriteDynamicPropsToStaticPropsFiles /p:GeneratingStaticPropertiesFile=true ${MSBUILD_ARGUMENTS[@]} "$@"
+$CLI_ROOT/dotnet $CLI_ROOT/sdk/$SDK_VERSION/MSBuild.dll /bl:$SCRIPT_ROOT/artifacts/log/Debug/Build_$LogDateStamp.binlog $SCRIPT_ROOT/build.proj ${MSBUILD_ARGUMENTS[@]} "$@"
diff --git a/tools-local/init-build.proj b/tools-local/init-build.proj
index 5109c03675..02dc6a4987 100644
--- a/tools-local/init-build.proj
+++ b/tools-local/init-build.proj
@@ -16,10 +16,6 @@
   <UsingTask AssemblyFile="$(XPlatSourceBuildTasksAssembly)" TaskName="NuGetPack" />
   <UsingTask AssemblyFile="$(XPlatSourceBuildTasksAssembly)" TaskName="ZipFileExtractToDirectory" />
 
-  <PropertyGroup>
-    <BuildCompetedSuccessSemaphore>$(BaseIntermediatePath)/init-build-proj.complete</BuildCompetedSuccessSemaphore>
-  </PropertyGroup>
-
   <ItemGroup>
     <BuildTasksTarget Include="Restore;Build;InstallResolver" />
   </ItemGroup>
@@ -28,12 +24,8 @@
     <BuildTasksOfflineSources>$(ReferencePackagesDir)%3B$(PrebuiltPackagesPath)</BuildTasksOfflineSources>
   </PropertyGroup>
 
-  <Target Name="Build"
-    Inputs="$(TargetInfoProps)"
-    Outputs="$(BuildCompetedSuccessSemaphore)"
-    >
+  <Target Name="Build">
     <CallTarget Targets="UnpackTarballs;BuildXPlatTasks;AcquireDarc;FetchSources;WriteSourceLinkMetadata;BuildTasks;ExtractToolPackage;WriteDynamicPropsToStaticPropsFiles;GenerateRootFs;ApplyPatches;PoisonPrebuiltPackages" />
-    <Touch Files="$(BuildCompetedSuccessSemaphore)" AlwaysCreate="true" />
   </Target>
 
   <Target Name="PrepareOfflineLocalTools"
@@ -42,11 +34,13 @@
             BuildXPlatTasks" />
 
   <Target Name="Clean">
-    <Delete Files="$(BuildCompetedSuccessSemaphore)" />
+    <Delete Files="$(CompletedSemaphorePath)*.*" />
   </Target>
 
   <Target Name="UnpackTarballs" 
-          Condition="'$(OfflineBuild)' == 'true'">
+          Condition="'$(OfflineBuild)' == 'true'"
+          Inputs="$(MSBuildProjectFullPath)" 
+          Outputs="$(CompletedSemaphorePath)UnpackTarballs.complete" >
     <MakeDir Directories="$(ReferencePackagesDir)"  Condition="'$(CustomReferencePackagesPath)' == ''" />
     <Exec Command="tar -xzf $(ExternalTarballsDir)$(ReferencePackagesTarballName).*.tar.gz"
           WorkingDirectory="$(ReferencePackagesDir)"
@@ -58,9 +52,13 @@
           Condition="'$(CustomPrebuiltSourceBuiltPackagesPath)' == ''" />
 
     <Copy SourceFiles="$(PrebuiltSourceBuiltPackagesPath)PackageVersions.props" DestinationFiles="$(IntermediatePath)SourceBuiltPackageVersions.props" />
+
+    <WriteLinesToFile File="$(CompletedSemaphorePath)UnpackTarballs.complete" Overwrite="true" />
   </Target>
 
-  <Target Name="BuildTasks">
+  <Target Name="BuildTasks" 
+          Inputs="$(MSBuildProjectFullPath)" 
+          Outputs="$(CompletedSemaphorePath)BuildTasks.complete" >
     <!--
       __ToolInitPhase ensures MSBuild reruns all the targets for each BuildTasksTarget. If we don't
       alter the global properties, we get a "hit" in MSBuild's target cache, and the props/targets
@@ -73,9 +71,14 @@
       Properties="
         RestoreSources=$(BuildTasksOfflineSources);
         __ToolInitPhase=%(BuildTasksTarget.Identity)" />
+ 
+    <WriteLinesToFile File="$(CompletedSemaphorePath)BuildTasks.complete" Overwrite="true" />
   </Target>
 
-  <Target Name="BuildXPlatTasks" DependsOnTargets="UnpackTarballs">
+  <Target Name="BuildXPlatTasks" 
+          DependsOnTargets="UnpackTarballs"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(CompletedSemaphorePath)BuildXPlatTasks.complete">
     <MSBuild
       Projects="
         tasks\Microsoft.DotNet.SourceBuild.Tasks.XPlat\Microsoft.DotNet.SourceBuild.Tasks.XPlat.csproj;
@@ -85,6 +88,8 @@
       Properties="
         RestoreSources=$(BuildTasksOfflineSources);
         __ToolInitPhase=%(BuildTasksTarget.Identity)" />
+
+    <WriteLinesToFile File="$(CompletedSemaphorePath)BuildXPlatTasks.complete" Overwrite="true" />
   </Target>
 
   <Target Name="GetRepoProjects">
@@ -103,7 +108,10 @@
      <Exec Condition="'$(Platform)' == 'armel'" Command="$(ArmEnvironmentVariables) $(ProjectDir)cross/armel/tizen-build-rootfs.sh" />
   </Target>
 
-  <Target Name="BuildReferenceAssemblies" Condition="'$(OfflineBuild)' == 'true'">
+  <Target Name="BuildReferenceAssemblies" 
+          Condition="'$(OfflineBuild)' == 'true'"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(CompletedSemaphorePath)BuildReferenceAssemblies.complete">
     <Message Importance="High" Text="[$([System.DateTime]::Now.ToString('HH:mm:ss.ff'))] Building reference-only assemblies." />
     <ItemGroup>
       <IlSource Include="$(ReferencePackagesSourceDir)**/*.il" />
@@ -122,18 +130,27 @@
                ExcludeEmptyDirectories="false"
                CreateSymbolPackage="false" />
     <Message Importance="High" Text="[$([System.DateTime]::Now.ToString('HH:mm:ss.ff'))] Done packing reference-only packages." />
+        
+    <WriteLinesToFile File="$(CompletedSemaphorePath)BuildReferenceAssemblies.complete" Overwrite="true" />
   </Target>
 
 
   <Target Name="ExtractToolPackage"
           DependsOnTargets="UnpackTarballs;BuildXPlatTasks"
-          Condition="'$(OfflineBuild)' == 'true'">
+          Condition="'$(OfflineBuild)' == 'true'"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(CompletedSemaphorePath)ExtractToolPackage.complete">
     <ZipFileExtractToDirectory SourceArchive="$(PrebuiltSourceBuiltPackagesPath)Microsoft.DotNet.Arcade.Sdk.$(ARCADE_BOOTSTRAP_VERSION).nupkg"
                                DestinationDirectory="$(ArcadeBootstrapPackageDir)microsoft.dotnet.arcade.sdk/$(ARCADE_BOOTSTRAP_VERSION)/"
                                OverwriteDestination="true" />
+        
+    <WriteLinesToFile File="$(CompletedSemaphorePath)ExtractToolPackage.complete" Overwrite="true" />
   </Target>
 
-  <Target Name="WriteDynamicPropsToStaticPropsFiles" DependsOnTargets="BuildTasks">
+  <Target Name="WriteDynamicPropsToStaticPropsFiles" 
+          DependsOnTargets="BuildTasks"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(CompletedSemaphorePath)WriteDynamicPropsToStaticPropsFiles.complete">
     <GetHostInformation Condition="'$(TargetRid)' == ''">
       <Output PropertyName="TargetRid" TaskParameter="Rid" />
     </GetHostInformation>
@@ -159,27 +176,42 @@
     </PropertyGroup>
     <MakeDir Directories="$(IntermediatePath)" Condition="!Exists('$(IntermediatePath)')" />
     <WriteLinesToFile File="$(TargetInfoProps)" Lines="$(TargetInfoPropsContent)" Overwrite="True" />
+        
+    <WriteLinesToFile File="$(CompletedSemaphorePath)WriteDynamicPropsToStaticPropsFiles.complete" Overwrite="true" />
   </Target>
 
-  <Target Name="PoisonPrebuiltPackages" Condition="'$(EnablePoison)' == 'true' and '$(OfflineBuild)' == 'true'">
+  <Target Name="PoisonPrebuiltPackages" 
+          Condition="'$(EnablePoison)' == 'true' and '$(OfflineBuild)' == 'true'"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(CompletedSemaphorePath)PoisonPrebuiltPackages.complete">
     <ItemGroup>
       <PrebuiltPackages Include="$(PrebuiltPackagesPath)**/*.nupkg" />
       <PrebuiltSourceBuiltPackages Include="$(PrebuiltSourceBuiltPackagesPath)**/*.nupkg" />
     </ItemGroup>
     <MarkAndCatalogPackages PackagesToMark="@(PrebuiltPackages)" CatalogOutputFilePath="$(PoisonReportDataFile)" MarkerFileName="$(PoisonMarkerFile)" />
     <MarkAndCatalogPackages PackagesToMark="@(PrebuiltSourceBuiltPackages)" CatalogOutputFilePath="$(SourceBuiltPoisonReportDataFile)" MarkerFileName="$(SourceBuiltPoisonMarkerFile)" />
+        
+    <WriteLinesToFile File="$(CompletedSemaphorePath)PoisonPrebuiltPackages.complete" Overwrite="true" />
   </Target>
 
   <Target Name="FetchSources"
           Condition="'$(OfflineBuild)' != 'true'"
-          DependsOnTargets="GetCommonDarcCloneCommand">
+          DependsOnTargets="GetCommonDarcCloneCommand"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(CompletedSemaphorePath)FetchSources.complete">
     <Message Importance="High" Text="[$([System.DateTime]::Now.ToString('HH:mm:ss.ff'))] Getting source code for repos in Version.Details.xml." />
     <Message Importance="High" Text="[$([System.DateTime]::Now.ToString('HH:mm:ss.ff'))] Running Darc command: '$(DarcCloneCommand)' from working dir $(ProjectDir)" />
     <Exec Command="$(DarcCloneCommand) --repos-folder $(DarcCloneReposFolder)" WorkingDirectory="$(ProjectDir)" />
     <Message Importance="High" Text="[$([System.DateTime]::Now.ToString('HH:mm:ss.ff'))] Done getting source code for repos in Version.Details.xml." />
+
+    <WriteLinesToFile File="$(CompletedSemaphorePath)FetchSources.complete" Overwrite="true" />
   </Target>
 
-  <Target Name="WriteSourceLinkMetadata" Condition="'$(OfflineBuild)' != 'true'" DependsOnTargets="AcquireDarc;FetchSources">
+  <Target Name="WriteSourceLinkMetadata" 
+          Condition="'$(OfflineBuild)' != 'true'" 
+          DependsOnTargets="AcquireDarc;FetchSources"
+          Inputs="$(MSBuildProjectFullPath)"
+          Outputs="$(CompletedSemaphorePath)WriteSourceLinkMetadata.complete">
     <Message Importance="High" Text="[$([System.DateTime]::Now.ToString('HH:mm:ss.ff'))] Writing out SourceLink metadata." />
     <WriteSourceRepoProperties
        VersionDetailsFile="$(RepositoryEngineeringDir)Version.Details.xml"
@@ -187,6 +219,8 @@
        ClonedSubmoduleDirectory="$(ClonedSubmoduleDirectory)"
        SourceBuildMetadataDir="$(GitInfoOutputDir)" />
     <Message Importance="High" Text="[$([System.DateTime]::Now.ToString('HH:mm:ss.ff'))] Done writing out SourceLink metadata." />
+
+    <WriteLinesToFile File="$(CompletedSemaphorePath)WriteSourceLinkMetadata.complete" Overwrite="true" />
   </Target>
 
 </Project>