Add custom claim to jwt

Ok, going further inside this rabbit hole. I made hello world rule:

function (user, context, callback) {
var namespace = ‘Pulsar Trading Capital’;
context.accessToken[namespace] = “world”;
callback(null, user, context);
}

Then I try to request for token and see that nothing changes. I googled around and found this topic:

next I try to add scope to my request like this:
“scope” : “Pulsar Trading Capital
and it gives me 403 with message
{

"error": "access_denied",

"error_description": "Client has not been granted scopes: https://pulsar.com/hello"

}
Then I found this Add API Permissions
But on my permissions page there is no fields and buttons to add new one; only a list of existing fields.
How do I proceed?