在Active Admin中使用自定义属性时，应该在pundit相关的文件中给出对应的策略，以确保属性被正确地使用。

例如，考虑一个支持自定义属性的Post模型，并且希望在Active Admin中使用pundit来控制访问。此时，可以在app/policies/post_policy.rb中定义PostPolicy类来包含有关自定义属性的信息：

class PostPolicy < ApplicationPolicy
  class Scope < Scope
    def resolve
      scope.all
    end
  end

  def initialize(user, record)
    @user = user
    @post = record
  end

  def show?
    true
  end

  # Allow editing if the user is an admin, or if the post is unpublished
  def edit?
    @user.admin? || !@post.published?
  end

  # Allow updating if the user is an admin, or if the post is unpublished
  def update?
    edit?
  end

  # Allow creation if the user is an admin, or if the custom flag is set
  def create?
    @user.admin? || @post.custom_flag?
  end

  # Allow deletion if the user is an admin, or if the post is unpublished
  def destroy?
    @user.admin? || !@post.published?
  end
end

然后，在Active Admin的配置文件中，继承ActiveAdmin::PunditAdapter并指定正确的策略类：

ActiveAdmin.setup do |config|
  config.authorization_adapter = ActiveAdmin::PunditAdapter

  config.on_unauthorized_access = :access_denied

  config.namespace :admin do |admin|
    admin.controller :posts do
      include Pundit

      # Use a custom policy for the Post model
      controller do
        def policy_class
          PostPolicy
        end
      end

      # The rest of the controller actions...
    end
  end
end

这样，就可以在Active Admin中使用自定义属性来控制访问。