ruby-sdk/lib/mcp/tool.rb

# frozen_string_literal: true

module MCP
  class Tool
    class << self
      NOT_SET = Object.new

      attr_reader :title_value
      attr_reader :description_value
      attr_reader :annotations_value
      attr_reader :meta_value

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

      def to_h
        {
          name: name_value,
          title: title_value,
          description: description_value,
          inputSchema: input_schema_value.to_h,
          outputSchema: @output_schema_value&.to_h,
          annotations: annotations_value&.to_h,
          _meta: meta_value,
        }.compact
      end

      def inherited(subclass)
        super
        subclass.instance_variable_set(:@name_value, nil)
        subclass.instance_variable_set(:@title_value, nil)
        subclass.instance_variable_set(:@description_value, nil)
        subclass.instance_variable_set(:@input_schema_value, nil)
        subclass.instance_variable_set(:@output_schema_value, nil)
        subclass.instance_variable_set(:@annotations_value, nil)
        subclass.instance_variable_set(:@meta_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 input_schema_value
        @input_schema_value || InputSchema.new
      end

      attr_reader :output_schema_value

      def title(value = NOT_SET)
        if value == NOT_SET
          @title_value
        else
          @title_value = value
        end
      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
        elsif value.is_a?(Hash)
          properties = value[:properties] || value["properties"] || {}
          required = value[:required] || value["required"] || []
          @input_schema_value = InputSchema.new(properties:, required:)
        elsif value.is_a?(InputSchema)
          @input_schema_value = value
        end
      end

      def output_schema(value = NOT_SET)
        if value == NOT_SET
          output_schema_value
        elsif value.is_a?(Hash)
          @output_schema_value = OutputSchema.new(value)
        elsif value.is_a?(OutputSchema)
          @output_schema_value = value
        end
      end

      def meta(value = NOT_SET)
        if value == NOT_SET
          @meta_value
        else
          @meta_value = value
        end
      end

      def annotations(hash = NOT_SET)
        if hash == NOT_SET
          @annotations_value
        else
          @annotations_value = Annotations.new(**hash)
        end
      end

      def define(name: nil, title: nil, description: nil, input_schema: nil, output_schema: nil, meta: nil, annotations: nil, &block)
        Class.new(self) do
          tool_name name
          title title
          description description
          input_schema input_schema
          meta meta
          output_schema output_schema
          self.annotations(annotations) if annotations
          define_singleton_method(:call, &block) if block
        end
      end
    end
  end
end