ruby-sdk/lib/model_context_protocol/tool.rb

# frozen_string_literal: true

module ModelContextProtocol
  class Tool
    class Response
      attr_reader :content, :is_error

      def initialize(content, is_error = false)
        @content = content
        @is_error = is_error
      end

      def to_h
        { content:, isError: is_error }.compact
      end
    end

    class << self
      NOT_SET = Object.new

      attr_reader :description_value
      attr_reader :input_schema_value

      def call(*args, context:)
        raise NotImplementedError, "Subclasses must implement call"
      end

      def to_h
        { name: name_value, description: description_value, inputSchema: input_schema_value }
      end

      def inherited(subclass)
        super
        subclass.instance_variable_set(:@name_value, nil)
        subclass.instance_variable_set(:@description_value, nil)
        subclass.instance_variable_set(:@input_schema_value, nil)
      end

      def tool_name(value = NOT_SET)
        if value == NOT_SET
          @name_value
        else
          @name_value = value
        end
      end

      def name_value
        @name_value || StringUtils.handle_from_class_name(name)
      end

      def description(value = NOT_SET)
        if value == NOT_SET
          @description_value
        else
          @description_value = value
        end
      end

      def input_schema(value = NOT_SET)
        if value == NOT_SET
          @input_schema_value
        else
          @input_schema_value = value
        end
      end

      def define(name: nil, description: nil, input_schema: nil, &block)
        Class.new(self) do
          tool_name name
          description description
          input_schema input_schema
          define_singleton_method(:call) do |*args, context:|
            instance_exec(*args, context:, &block)
          end
        end
      end
    end
  end
end