Redirect Rule during Signup

I want to redirect the user whenever he signs up, so that before saving him in our database, i am able to take some more details.
For this, I am going to redirect to a page on our site where we will collect more data, send it to backend server and then continue later using the state. For this, I also want to send the accessToken generated on Auth0 for security reasons. I don’t want attackers trying to send their custom requests, our server will verify token to authenticate the request(I hope i am right about this?).

However, how do I access the accessToken string from the context object?
Here is what I have now:

function (user, context, callback) {
  if (context.stats.loginsCount === 1) {
		context.redirect = {
    	url: `https://xx-staging.com/auth0-signup?email=${user.email}&accessToken=${}`  //where do i add access token?
		};
  }
  callback(null, user, context);
}

Docs state that:

context.accessToken An object representing the options defined on the Access Token.

How do I get the string rather than the object because this is not documented here?

Hey there,

I checked our docs on rules:

and found this:

So context as well as accessToken are objects so they both have properties that you can access.