The screen of the admin that is open, by the same names as "I go to the admin screen". The route after /ghost/#/ is compared; with "not", the step passes when the admin is anywhere else.
Examples
Then I should be on the admin screen "Posts"
Then I should be on the admin screen "Tags"
Then we should be on the admin screen "Drafts"
Then I should not be on the admin screen "Settings"
And I should be on the admin screen "sign in"
Pattern
Then(/^(?:I |we )?should( not)? be on the admin screen "([^"]*)"$/, …)
Part of @webship-js/ghost-steps (github.com/webship/ghost-steps), a step pack for Webship-js 2.0.x.