Fix

src/applications/temporal_worker/__main__.py

@@ -47,7 +47,7 @@ async def main():
             twitch_activities.check_streams_states,
             twitch_activities.on_redemption_reward_add_activity,
         ],
-        workflow_runner=UnsandboxedWorkflowRunner(),
+        workflow_runner=UnsandboxedWorkflowRunner()
     )
 
     await worker.run()

src/applications/twitch_webhook/activities/on_state_change.py

@@ -1,12 +1,12 @@
 from temporalio import activity
-from dataclasses import dataclass
+
+from pydantic import BaseModel
 
 from applications.twitch_webhook.state import State, EventType
 from applications.twitch_webhook.watcher import StateWatcher
 
 
-@dataclass
+class OnStreamStateChangeActivity(BaseModel):
-class OnStreamStateChangeActivity:
     streamer_id: int
     event_type: EventType
     new_state: State | None = None

src/core/temporal.py

@@ -1,5 +1,10 @@
 from temporalio.client import Client
+from temporalio.contrib.pydantic import pydantic_data_converter
 
 
 async def get_client() -> Client:
-    return await Client.connect("temporal:7233", namespace="default")
+    return await Client.connect(
+        "temporal:7233",
+        namespace="default",
+        data_converter=pydantic_data_converter
+    )