diff --git a/agentkit/apps/a2a_app/a2a_app.py b/agentkit/apps/a2a_app/a2a_app.py
index 37e9c711..1d079322 100644
--- a/agentkit/apps/a2a_app/a2a_app.py
+++ b/agentkit/apps/a2a_app/a2a_app.py
@@ -46,6 +46,7 @@ async def wrapper(*args, **kwargs):
 
         with telemetry.tracer.start_as_current_span(name="a2a_invocation") as span:
             exception = None
+            result = None
             try:
                 result = await execute_func(
                     executor_instance, context=context, event_queue=event_queue
diff --git a/agentkit/apps/agent_server_app/agent_server_app.py b/agentkit/apps/agent_server_app/agent_server_app.py
index 3988e427..6872c9a7 100644
--- a/agentkit/apps/agent_server_app/agent_server_app.py
+++ b/agentkit/apps/agent_server_app/agent_server_app.py
@@ -618,7 +618,9 @@ async def event_generator():
                         telemetry.trace_agent_server_finish(
                             path="/invoke", func_result="", exception=e
                         )
-                        error_payload = f'data: {{"error": "{str(e)}"}}\n\n'
+                        error_payload = (
+                            "data: " + json.dumps({"error": str(e)}) + "\n\n"
+                        )
                 if error_payload is not None:
                     # The identity path never suspends while retaining the
                     # original exception or its credential-bearing traceback.