Entity Framework Core 2.0 Add-Migration non crea alcun file di migrazione

Migrazione recente da EF Core 1.0 a EF Core 2.0 e funziona correttamente. Oggi ho aggiunto una nuova tabella (in codice prima) e l'ho aggiunta al mio DbContext con:

public virtual DbSet<Foo> Foos { get; set; }

Quando eseguo una migrazione, con il mio DbContext in un progetto separato (ricorda che tutto funzionava prima), la migrazione termina, ma non sono stati creati file di migrazione. Tutto questo funzionava prima del Core 2.0 usando:

http://paultechguy.blogspot.com/2017/04/entity-framework-core-migrating-and.html

PM> Add-Migration GradePremade -project Mfc.MfcRepositoryModel -verbose -context MfcDbContext -StartupProject web.xyz
Using project 'class.xyz\Mfc.MfcRepositoryModel'.
Using startup project 'web.xyz'.
Build started...
Build succeeded.
C:\Program Files\dotnet\dotnet.exe exec --depsfile C:\development\xyz\web.xyz\bin\Debug\netcoreapp2.0\web.xyz.deps.json --additionalprobingpath C:\Users\pcarver\.nuget\packages --additionalprobingpath "C:\Program Files\dotnet\sdk\NuGetFallbackFolder" --runtimeconfig C:\development\xyz\web.xyz\bin\Debug\netcoreapp2.0\web.xyz.runtimeconfig.json "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.entityframeworkcore.tools\2.0.0\tools\netcoreapp2.0\ef.dll" migrations add GradePremade --json --context MfcDbContext --verbose --no-color --prefix-output --assembly C:\development\xyz\web.xyz\bin\Debug\netcoreapp2.0\Mfc.MfcRepositoryModel.dll --startup-assembly C:\development\xyz\web.xyz\bin\Debug\netcoreapp2.0\web.xyz.dll --project-dir C:\development\xyz\class.xyz\Mfc.MfcRepositoryModel --root-namespace Mfc.MfcRepositoryModel
Using assembly 'Mfc.MfcRepositoryModel'.
Using startup assembly 'web.xyz'.
Using application base 'C:\development\xyz\web.xyz\bin\Debug\netcoreapp2.0'.
Using working directory 'C:\development\xyz\web.xyz'.
Using root namespace 'Mfc.MfcRepositoryModel'.
Using project directory 'C:\development\xyz\class.xyz\Mfc.MfcRepositoryModel'.
Finding DbContext classes...
Finding IDesignTimeDbContextFactory implementations...
Finding application service provider...
Finding BuildWebHost method...
No BuildWebHost method was found on type 'xyz.Program'.
No application service provider was found.
Finding DbContext classes in the project...
Found DbContext 'ApplicationDbContext'.
Found DbContext 'MfcDbContext'.
Using DbContext factory 'MfcContextFactory'.
Using context 'MfcDbContext'.
Finding design-time services for provider 'Microsoft.EntityFrameworkCore.SqlServer'...
Using design-time services from provider 'Microsoft.EntityFrameworkCore.SqlServer'.
Finding IDesignTimeServices implementations in assembly 'web.xyz'...
No design-time services were found.

Nessun errore che mi sembra ovvio e nessun file di migrazione creato. Ho fatto un Remove-Migration per iniziare pulito, ma ancora senza workie.