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Project Type Detection

Preview Build SDK Reviewed 2026-09-16 purview-dev/build-sdk central-package-management code-style csharp developer-experience developer-tooling devex dotnet msbuild msbuild-sdk nuget project-templates roslyn roslyn-analyzers roslyn-generators tunit xunit

Project Type Detection

Section titled “Project Type Detection”

During Sdk.props evaluation the SDK classifies every .csproj by reading the project filename, the Sdk attribute, and on-disk markers. The resulting flags drive the defaults described throughout this wiki.

Detection flags

Section titled “Detection flags”
Flag Condition
IsCSharpProject Project file extension is .csproj.
IsTestProject Project name ends with Test/Tests and carries a recognised TestingType suffix.
IsSharedTestingProject Project name is one of SharedTestingFramework, SharedTestingInfrastructure, SharedTestingInfra, SharedTestingUtilities, SharedTestingUtils, SharedTestingLibrary, SharedTestingLib, SharedTestingHelpers.
IsSharedProject Project name is one of Shared, SharedFramework, SharedInfrastructure, SharedInfra, SharedUtilities, SharedUtils, SharedLibrary, SharedLib, SharedHelpers.
IsContainerProject A Dockerfile, dockerfile, or Dockerfile.dev exists in the project directory.
IsSdkProject An Sdk value is parsed from the <Project>/<Import> element.
IsWebSdkProject SdkProjectName is Microsoft.NET.Sdk.Web.
IsWorkerSdkProject SdkProjectName is Microsoft.NET.Sdk.Worker.
IsAspireHostProject SdkProjectName starts with Aspire.Sdk.Host or Aspire.AppHost.Sdk.
IsCLIProject Project name ends with CLI, Console, CommandLine, QuickStart, or QuickStarts.
IsRoslynComponent <IsRoslynComponent>true</IsRoslynComponent> is declared in the project file.
IsPackable <IsPackable>true</IsPackable> is declared in the project file.
IsWebProject Marker used in SDK web-project behaviour.

TestingType is the detected test category suffix from the project name (for example Unit, Integration, E2E); TargetProjectName is the inferred non-test project name that a test project targets.

What each type gets

Section titled “What each type gets”

Test projects (IsTestProject=true)

Section titled “Test projects (IsTestProject=true)”
  • OutputType=Exe when the testing framework is not None.
  • CollectCoverage=true with coverage exclusions for framework and mocking packages.
  • IsPackable=false, IsPublishable=false, MaxCpuCount=0.
  • Disabled native instrumentation by default.
  • An [assembly: ExcludeFromCodeCoverage] attribute.
  • Automatic ProjectReference to the target project (resolved as ../<TargetProjectName>/, sibling src/ paths, and the shared testing project alongside).
  • A [Category: <TestingType>] assembly attribute (TUnit) or [Trait("Category", ...)] (Xunit).

Shared testing projects (IsSharedTestingProject=true)

Section titled “Shared testing projects (IsSharedTestingProject=true)”
  • Test package references, but not the test runner or coverage settings.
  • A [Skip] attribute (TUnit) so the shared assembly is never executed directly.
  • TUnit.Core instead of the full TUnit package.

Shared projects (IsSharedProject=true)

Section titled “Shared projects (IsSharedProject=true)”
  • Automatically referenced by sibling non-test projects via wildcard (../Shared*/Shared*.csproj); test projects automatically reference ../SharedTesting*/SharedTesting*.csproj.

Container projects

Section titled “Container projects”
  • InvariantGlobalization=true, PublishAot=true, DockerDefaultTargetOS=Linux, DockerfileContext=..\..\.
  • Adds Microsoft.VisualStudio.Azure.Containers.Tools.Targets.

Web SDK projects (IsWebSdkProject=true)

Section titled “Web SDK projects (IsWebSdkProject=true)”
  • Non-API web apps get InterceptorsNamespaces extended with Microsoft.AspNetCore.OpenApi.Generated for OpenAPI interceptors.

CLI projects

Section titled “CLI projects”
  • OutputType=Exe, appsettings*.json copied to the output directory.
  • CA1515 suppressed (nested settings classes on internal commands).

Aspire host projects

Section titled “Aspire host projects”
  • OutputType=Exe (when not a test/shared-testing project), CA1515 suppressed.

Roslyn components (IsRoslynComponent=true)

Section titled “Roslyn components (IsRoslynComponent=true)”
  • Default netstandard2.0 target, LangVersion=latest, Nullable=enable, TreatWarningsAsErrors=true, EnforceExtendedAnalyzerRules=true, Deterministic=true.
  • Compiler-generated output under the intermediate directory, no dependency file.
  • No symbol package by default; the PDB ships beside the analyzer in the package.
  • SourceLink with EmbedUntrackedSources=true, telemetry excluded.
  • See Packaging for how the analyzer assets are packed.

Packable projects (IsPackable=true)

Section titled “Packable projects (IsPackable=true)”
  • GenerateDocumentationFile, IncludeSource, IncludeSymbols (.snupkg), PublishRepositoryUrl, EmbedUntrackedSources, DebugType=portable defaults.
  • See Packaging.

Properties exposed to the compiler

Section titled “Properties exposed to the compiler”

The detection flags (plus many SDK properties) are exposed to Roslyn analyzers and source generators via CompilerVisibleProperty, readable as build_property.<PropertyName>. The full list is in the Configuration Reference.