dry-validation, custom field name

1

I’m trying to output a custom field name for a validation:

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'dry-validation'
end

require 'dry-validation'

class RowValidator < Dry::Validation::Contract
  params do
    required(:amount).filled(:integer, gt?: 0)
  end

  def self.messages
    super.merge(en: {
      dry_validation: {
        rules: {
          amount: "Amount (column 1)",
        },
      }
    })
  end
end

validator = RowValidator.new
p validator.call(amount: 0).errors(full: true).map(&:text)

This is outputting “amount must be greater than 0”, but I’d like it to be “Amount (column 1) must be greater than 0”.

Is there a way to do this without using an external i18n file?