The contract

The gem has two opinions about your app:

context.current_user.can?(:symbol)         # => true/false  (required)
context.current_user.default_for(:symbol)  # => value | nil (optional)

can? gates visibility -- fields, variants, and entire tools. default_for populates JSON Schema default values from the current user's context. The symbols can mean anything:

current_user.can?(:manage_workflows)  # permission
current_user.can?(:backward_routing)  # feature flag
current_user.can?(:enterprise_plan)   # plan tier
current_user.can?(:experiment_v2)     # A/B test

current_user.default_for(:timezone)   # => "America/Chicago"
current_user.default_for(:locale)     # => "en-US"

default_for is optional. If you don't use @default_for tags, you don't need it. When present, it's a simple case statement -- no metaprogramming:

def default_for(key)
  case key
  when :timezone then timezone
  when :locale then locale
  end
end

Collected from README.md in the repository. Edit it there, not here.