diff --git a/shared/workspaces/test/test_capability_service.py b/shared/workspaces/test/test_capability_service.py
index 4a76bb63c9da4d856268d6d6bb7b365b91a0d7c5..909b93dd2cb270e4f2d9f86438dd7c46cc3a9063 100644
--- a/shared/workspaces/test/test_capability_service.py
+++ b/shared/workspaces/test/test_capability_service.py
@@ -65,7 +65,7 @@ class TestCapabilityService:
             "service": "capability",
             "routing_key": "capability",
             "carta_url": carta_url,
-            "subject": "Your CARTA Session is ready!",
+            "subject": {"workflow_request_id": wf_request_id},
             "type": "carta-ready",
         }
 
@@ -75,7 +75,7 @@ class TestCapabilityService:
             "workspaces.capability.services.capability_info.CapabilityInfo.lookup_execution_by_workflow_request_id",
             return_value=mock_capability_execution,
         ):
-            mock_capability_service.on_carta_ready(wf_request_id, **fake_carta_ready_msg)
+            mock_capability_service.on_carta_ready(**fake_carta_ready_msg)
             assert mock_capability_info.save_entity.call_count == save_entity_old_call_count + 1
 
             (request_version,) = mock_capability_info.save_entity.call_args.args
diff --git a/shared/workspaces/workspaces/capability/services/capability_service.py b/shared/workspaces/workspaces/capability/services/capability_service.py
index a7b492d768dd0dae603e4816b7238b42efcda1e9..1791f9c7b0524879cf1272ba6c3dbbb53dfbeeb6 100644
--- a/shared/workspaces/workspaces/capability/services/capability_service.py
+++ b/shared/workspaces/workspaces/capability/services/capability_service.py
@@ -152,7 +152,7 @@ class CapabilityService(CapabilityServiceIF):
         self.capability_info.save_entity(request)
 
     @on_message(type="carta-ready")
-    def on_carta_ready(self, cp_request_id: int, **message: Dict[str, str]):
+    def on_carta_ready(self, **message: Dict[str, str]):
         """
         Catch the RH-flavored event and save it to the capability request version metadata
 
@@ -161,7 +161,9 @@ class CapabilityService(CapabilityServiceIF):
         """
         logger.info(f"RECEIVED CARTA READY MESSAGE: {message}")
 
-        execution = self.capability_info.lookup_execution_by_workflow_request_id(cp_request_id)
+        wf_request_id = int(message["subject"]["workflow_request_id"])
+
+        execution = self.capability_info.lookup_execution_by_workflow_request_id(wf_request_id)
         request_version = execution.version
         request_version.workflow_metadata = {"carta_url": message["carta_url"]}