I was trying to create a migration in a new project within a solution and received the following error:
Your startup project ‘SubscriptionManagementGrpcService’ doesn’t reference Microsoft.EntityFrameworkCore.Design. This package is required for the Entity Framework Core Tools to work. Ensure your startup project is correct, install the package, and try again.
The error was a bit confusing because all of my migrations for the rest of the solution were still working and none of my other startup projects had Microsoft.EntityFrameworkCore.Design as a reference.
After a bit of comparing I realised that the other projects all referenced data projects that in turn referenced Microsoft.EntityFramework.Design. Adding the package reference to the subscription data library referenced by my GrpcService fixed the issue.