Example on how you could implement a @wip tag in specflow

SpecFlowTags.cs

namespace SpecFlow.Extensions
{
    [Binding]
    public class Tags
    {
        [AfterScenario("wip")]
        public static void Wip()
        {
            if (ScenarioContext.Current.TestError == null || ScenarioContext.Current.TestError is SuccessException)
            {
                var message = @"Please remove the @wip tag from completed scenario: '{0}'";
                throw new RemoveTagException(string.Format(message, ScenarioContext.Current.ScenarioInfo.Title));
            }
        }
    }

    public class RemoveTagException : Exception
    {
        public RemoveTagException(string message) : base(message)
        {
        }
    }
}