refactor: share tool schema validation helpers

Author: atesgoral

lib/mcp/tool.rb

@@ -93,23 +93,29 @@ def icons(value = NOT_SET)
       def input_schema(value = NOT_SET)
         if value == NOT_SET
           input_schema_value
-        elsif value.is_a?(Hash)
-          @input_schema_value = InputSchema.new(value)
-        elsif value.is_a?(InputSchema)
-          @input_schema_value = value
+        elsif (schema = coerce_schema(value, InputSchema))
+          @input_schema_value = schema
         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
+        elsif (schema = coerce_schema(value, OutputSchema))
+          @output_schema_value = schema
         end
       end
 
+      def coerce_schema(value, schema_class)
+        case value
+        when Hash
+          schema_class.new(value)
+        when schema_class
+          value
+        end
+      end
+      private :coerce_schema
+
       def meta(value = NOT_SET)
         if value == NOT_SET
           @meta_value

lib/mcp/tool/input_schema.rb

@@ -18,10 +18,7 @@ def missing_required_arguments(arguments)
       end
 
       def validate_arguments(arguments)
-        errors = fully_validate(arguments)
-        if errors.any?
-          raise ValidationError, "Invalid arguments: #{errors.join(", ")}"
-        end
+        validate_payload!(arguments, "arguments")
       end
     end
   end

lib/mcp/tool/output_schema.rb

@@ -8,10 +8,7 @@ class OutputSchema < Schema
       class ValidationError < StandardError; end
 
       def validate_result(result)
-        errors = fully_validate(result)
-        if errors.any?
-          raise ValidationError, "Invalid result: #{errors.join(", ")}"
-        end
+        validate_payload!(result, "result")
       end
     end
   end

lib/mcp/tool/schema.rb

@@ -31,6 +31,13 @@ def to_h
 
       private
 
+      def validate_payload!(payload, label)
+        errors = fully_validate(payload)
+        if errors.any?
+          raise self.class::ValidationError, "Invalid #{label}: #{errors.join(", ")}"
+        end
+      end
+
       def fully_validate(data)
         JSON::Validator.fully_validate(schema_for_validation, data)
       end