diff --git a/CHANGELOG.md b/CHANGELOG.md
index 104629b..42d82cd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Added `Unauthorized` response template
 - Added `ServiceUnavailable` response template
 
+### Fixed
+
+- Fixed `Pragma::Operation::Error#as_json` having the wrong arity
+
 ## [2.0.0]
 
 First Pragma 2 release.
diff --git a/lib/pragma/operation/error.rb b/lib/pragma/operation/error.rb
index 5f51304..26e5cb6 100644
--- a/lib/pragma/operation/error.rb
+++ b/lib/pragma/operation/error.rb
@@ -11,7 +11,7 @@ def initialize(error_type:, error_message:, meta: {})
         @meta = meta
       end
 
-      def as_json
+      def as_json(*)
         {
           error_type: error_type,
           error_message: error_message,