converting file path to URI using standard libraries

Author: dr03ramos

lib/mcp/tool/input_schema.rb

@@ -50,7 +50,9 @@ def validate_schema!
           accept_uri: false,
           accept_file: ->(path) { path.to_s.start_with?(Gem.loaded_specs["json-schema"].full_gem_path) },
         )
-        metaschema = "file://#{JSON::Validator.validator_for_name("draft4").metaschema}"
+        metaschema_path = Pathname.new(JSON::Validator.validator_for_name("draft4").metaschema)
+        metaschema_uri = URI::File.build(host: "", path: metaschema_path.expand_path.cleanpath.to_s.tr("\\", "/"))
+        metaschema = metaschema_uri.to_s
         errors = JSON::Validator.fully_validate(metaschema, schema, schema_reader: schema_reader)
         if errors.any?
           raise ArgumentError, "Invalid JSON Schema: #{errors.join(", ")}"

lib/mcp/tool/output_schema.rb

@@ -42,7 +42,9 @@ def validate_schema!
           accept_uri: false,
           accept_file: ->(path) { path.to_s.start_with?(Gem.loaded_specs["json-schema"].full_gem_path) },
         )
-        metaschema = JSON::Validator.validator_for_name("draft4").metaschema
+        metaschema_path = Pathname.new(JSON::Validator.validator_for_name("draft4").metaschema)
+        metaschema_uri = URI::File.build(host: "", path: metaschema_path.expand_path.cleanpath.to_s.tr("\\", "/"))
+        metaschema = metaschema_uri.to_s
         errors = JSON::Validator.fully_validate(metaschema, schema, schema_reader: schema_reader)
         if errors.any?
           raise ArgumentError, "Invalid JSON Schema: #{errors.join(", ")}"