// Add the DaprHeaderOperationFilter class somewhere in your solution... 

// Then in program.cs, I do something like this:

​

//builder.Services.AddEndpointsApiExplorer();

//if (builder.Environment.IsDevelopment())

//{

//  var token = Environment.GetEnvironmentVariable("APP_API_TOKEN");

//  builder.Services.AddSwaggerGen(options =>

//  {

//    options.OperationFilter<DaprHeaderOperationFilter>(token);

//  });

//}

//else

//{

//  builder.Services.AddSwaggerGen();

//}

​

public class DaprHeaderOperationFilter : IOperationFilter

{

  private readonly string _defaultToken;

  public DaprHeaderOperationFilter()

  {

    _defaultToken = string.Empty;

  }

​

  public DaprHeaderOperationFilter(string? token)

  {

    _defaultToken = token ?? string.Empty;

  }

​

  public void Apply(OpenApiOperation operation, OperationFilterContext context)

  {

    operation.Parameters ??= new List<OpenApiParameter>();

​

    operation.Parameters.Add(new OpenApiParameter

    {

      Name = "dapr-api-token",

      In = ParameterLocation.Header,

      Description = "Dapr API Token",

      Required = true,

      Schema = new OpenApiSchema

      {

        Type = "string",

        Default = new OpenApiString(_defaultToken)

      }

    });

  }

}