diff --git a/changelog/0000.fixed.md b/changelog/0000.fixed.md
new file mode 100644
index 000000000..39fabc029
--- /dev/null
+++ b/changelog/0000.fixed.md
@@ -0,0 +1,7 @@
+- Fixed Genesys AudioHook serializer to always include the `parameters` field in
+  protocol messages. The AudioHook protocol requires every message to carry a
+  `parameters` object (even if empty), but `_create_message` omitted it when no
+  parameters were provided. This caused clients that validate message structure
+  (including the Genesys reference implementation) to reject `pong` and
+  parameter-less `closed` responses, breaking server sequence tracking and
+  preventing `outputVariables` from reaching the Architect flow.
diff --git a/src/pipecat/serializers/genesys.py b/src/pipecat/serializers/genesys.py
index 2cc3c32db..4e0c11504 100644
--- a/src/pipecat/serializers/genesys.py
+++ b/src/pipecat/serializers/genesys.py
@@ -336,8 +336,7 @@ class GenesysAudioHookSerializer(FrameSerializer):
         if include_position:
             msg["position"] = self._format_position(self._position)
 
-        if parameters:
-            msg["parameters"] = parameters
+        msg["parameters"] = parameters if parameters is not None else {}
 
         return msg
 
diff --git a/tests/genesys/test_genesys_serializer.py b/tests/genesys/test_genesys_serializer.py
index 03132d7cb..1f63ae94e 100644
--- a/tests/genesys/test_genesys_serializer.py
+++ b/tests/genesys/test_genesys_serializer.py
@@ -76,6 +76,7 @@ class TestGenesysAudioHookSerializer:
 
         assert msg["type"] == "pong"
         assert msg["id"] == serializer.session_id
+        assert msg["parameters"] == {}
 
     def test_create_closed_response(self):
         """Test creating a closed response message."""
@@ -86,7 +87,7 @@ class TestGenesysAudioHookSerializer:
 
         assert msg["type"] == "closed"
         assert serializer.is_open is False
-        assert "parameters" not in msg  # No parameters when no output_variables
+        assert msg["parameters"] == {}  # Empty parameters when no output_variables
 
     def test_create_closed_response_with_output_variables(self):
         """Test creating a closed response with custom output variables."""