How can I completely disable a NuGet package's .NET analyzers in my project?

When analyzers are brought in as part of a NuGet package, the ExcludeAssets setting on your direct PackageReference may not prevent them from being loaded if the package itself declares the analyzer assets. That is, ExcludeAssets applies only to assets in the package you reference directly—and if the library’s package “LibraryWithAnalyzers” brings in its own analyzers without marking them as private, they’re still added transitively.

If you want to completely prevent any analyzers from running in your project, one option is to disable running analyzers during the build by adding the following property in your project file:

XMLCopied
<PropertyGroup>
  <RunAnalyzersDuringBuild>false</RunAnalyzersDuringBuild>
</PropertyGroup>

This property tells the build not to run any analyzers at all. Keep in mind that this disables all analyzers, not just the ones coming from that package.

The other option would be to use suppression mechanisms (such as .editorconfig or NoWarn) to ignore the analyzer diagnostics, but as you’ve noted your goal is to prevent execution altogether.

So in short, the ExcludeAssets setting on your PackageReference doesn’t affect the analyzer assets that are “baked into” the package; to prevent analyzers from running, you need to disable them at the project level via a property like RunAnalyzersDuringBuild.