Add-Migration showing error EntityFrameworkCore.Design is not installed

Check that your project.json contains these entries

under dependencies:

"Microsoft.EntityFrameworkCore.Design": {
  "version": "1.0.0-preview2-final",
  "type": "build"
},

"Microsoft.EntityFrameworkCore.SqlServer": "1.0.1",

under tools:

"Microsoft.EntityFrameworkCore.Tools": {
  "version": "1.0.0-preview2-final",
  "imports": [
    "portable-net45+win8+dnxcore50",
    "portable-net45+win8"
  ]
},

First, this document using VS2015 Update2 and current latest version for VS2015 is Update 3. So I suggest you upgrade your VS2015 to Update 3, which has fixed a lot of VS bugs.

Then according to the tutorial, I get the same error message when I run the command Add-Migration MyFirstMigration. Then I run command "Install-Package Microsoft.EntityFrameworkCore.Design" in Package Manager Console to install the EntityFrameworkCore.Design. After install it, when I run the command Add-Migration MyFirstMigration, it added successful.

Following is my project.json file content. Please check the dependencies and tools version. Make sure they are in correct versions.

"dependencies": {
"Microsoft.NETCore.App": {
  "version": "1.0.0",
  "type": "platform"
},
"Microsoft.AspNetCore.Diagnostics": "1.0.0",
"Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
"Microsoft.AspNetCore.Server.Kestrel": "1.0.0",
"Microsoft.Extensions.Logging.Console": "1.0.0",
"Microsoft.EntityFrameworkCore.SqlServer": "1.0.1",
"Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview3-final",
"Microsoft.EntityFrameworkCore.Design": "1.0.1"
},

"tools": {
"Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final",
"Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final"
},