Refactor MCP tool and server to handle optional server_context parameter

- Updated `call` method in `MCP::Tool` and `MCP::Prompt` to accept `server_context` as an optional parameter.
- Refactored `MCP::Server` to streamline argument handling for tool and prompt calls, introducing helper methods `call_tool_with_args` and `call_prompt_template_with_args`.
- Adjusted tests to reflect changes in method signatures and ensure compatibility with optional `server_context` parameter.

Author: julianojulio

lib/mcp/prompt.rb

@@ -9,7 +9,7 @@ class << self
       attr_reader :description_value
       attr_reader :arguments_value
 
-      def template(args, server_context:)
+      def template(args, server_context: nil)
         raise NotImplementedError, "Subclasses must implement template"
       end
 
@@ -57,7 +57,7 @@ def define(name: nil, description: nil, arguments: [], &block)
           prompt_name name
           description description
           arguments arguments
-          define_singleton_method(:template) do |args, server_context:|
+          define_singleton_method(:template) do |args, server_context: nil|
             instance_exec(args, server_context:, &block)
           end
         end

lib/mcp/server.rb

@@ -211,13 +211,7 @@ def call_tool(request)
       end
 
       begin
-        call_params = tool_call_parameters(tool)
-
-        if call_params.include?(:server_context)
-          tool.call(**arguments.transform_keys(&:to_sym), server_context:).to_h
-        else
-          tool.call(**arguments.transform_keys(&:to_sym)).to_h
-        end
+        call_tool_with_args(tool, arguments)
       rescue => e
         raise RequestHandlerError.new("Internal error calling tool #{tool_name}", request, original_error: e)
       end
@@ -242,7 +236,7 @@ def get_prompt(request)
       prompt_args = request[:arguments]
       prompt.validate_arguments!(prompt_args)
 
-      prompt.template(prompt_args, server_context:).to_h
+      call_prompt_template_with_args(prompt, prompt_args)
     end
 
     def list_resources(request)
@@ -292,5 +286,33 @@ def tool_call_method_def(tool)
         method
       end
     end
+
+    def call_tool_with_args(tool, arguments)
+      args = arguments.transform_keys(&:to_sym)
+
+      # Check if the tool accepts server_context or has **kwargs
+      parameters = tool.method(:call).parameters
+      accepts_server_context = parameters.any? { |_type, name| name == :server_context }
+      has_kwargs = parameters.any? { |type, _| type == :keyrest }
+
+      if accepts_server_context || has_kwargs
+        tool.call(**args, server_context: server_context).to_h
+      else
+        tool.call(**args).to_h
+      end
+    end
+
+    def call_prompt_template_with_args(prompt, args)
+      # Check if the prompt accepts server_context or has **kwargs
+      parameters = prompt.method(:template).parameters
+      accepts_server_context = parameters.any? { |_type, name| name == :server_context }
+      has_kwargs = parameters.any? { |type, _| type == :keyrest }
+
+      if accepts_server_context || has_kwargs
+        prompt.template(args, server_context: server_context).to_h
+      else
+        prompt.template(args).to_h
+      end
+    end
   end
 end

lib/mcp/tool.rb

@@ -9,7 +9,7 @@ class << self
       attr_reader :input_schema_value
       attr_reader :annotations_value
 
-      def call(*args, server_context:)
+      def call(*args, server_context: nil)
         raise NotImplementedError, "Subclasses must implement call"
       end