diff --git a/backend/packages/harness/deerflow/runtime/runs/execution/executor.py b/backend/packages/harness/deerflow/runtime/runs/execution/executor.py
index 80bcf281d..bb6416039 100644
--- a/backend/packages/harness/deerflow/runtime/runs/execution/executor.py
+++ b/backend/packages/harness/deerflow/runtime/runs/execution/executor.py
@@ -10,7 +10,8 @@ from ..domain import Run
 class RunExecutor(Protocol):
     """Executes one run against the underlying agent or graph runtime."""
 
-    async def execute(self, run: Run) -> None: ...
+    async def execute(self, run: Run) -> None:
+        pass
 
 
 __all__ = [
diff --git a/backend/packages/harness/deerflow/runtime/runs/execution/scheduler.py b/backend/packages/harness/deerflow/runtime/runs/execution/scheduler.py
index d9f8adbde..4c658c286 100644
--- a/backend/packages/harness/deerflow/runtime/runs/execution/scheduler.py
+++ b/backend/packages/harness/deerflow/runtime/runs/execution/scheduler.py
@@ -16,7 +16,8 @@ class RunExecutionHandle:
 class RunExecutionScheduler(Protocol):
     """Starts background execution for an accepted run."""
 
-    async def start(self, run_id: RunId) -> RunExecutionHandle: ...
+    async def start(self, run_id: RunId) -> RunExecutionHandle:
+        pass
 
 
 __all__ = [
diff --git a/backend/packages/harness/deerflow/runtime/runs/execution/supervisor.py b/backend/packages/harness/deerflow/runtime/runs/execution/supervisor.py
index 3acfcdef5..902bba387 100644
--- a/backend/packages/harness/deerflow/runtime/runs/execution/supervisor.py
+++ b/backend/packages/harness/deerflow/runtime/runs/execution/supervisor.py
@@ -10,7 +10,8 @@ from ..domain import CancelAction, RunId
 class RunSupervisor(Protocol):
     """Controls lifecycle operations for already scheduled runs."""
 
-    async def cancel(self, run_id: RunId, *, action: CancelAction = CancelAction.interrupt) -> bool: ...
+    async def cancel(self, run_id: RunId, *, action: CancelAction = CancelAction.interrupt) -> bool:
+        pass
 
 
 __all__ = [
diff --git a/backend/packages/harness/deerflow/runtime/runs/repositories/run_event_log.py b/backend/packages/harness/deerflow/runtime/runs/repositories/run_event_log.py
index 5fdaa1d63..9b21580e3 100644
--- a/backend/packages/harness/deerflow/runtime/runs/repositories/run_event_log.py
+++ b/backend/packages/harness/deerflow/runtime/runs/repositories/run_event_log.py
@@ -13,7 +13,8 @@ if TYPE_CHECKING:
 class RunEventLog(Protocol):
     """Persistence boundary for run messages and execution trace events."""
 
-    async def append(self, events: list[RunEvent]) -> list[StoredRunEvent]: ...
+    async def append(self, events: list[RunEvent]) -> list[StoredRunEvent]:
+        pass
 
     async def list_messages_by_run(
         self,
@@ -23,7 +24,8 @@ class RunEventLog(Protocol):
         limit: int = 50,
         before_seq: int | None = None,
         after_seq: int | None = None,
-    ) -> list[RunMessageView]: ...
+    ) -> list[RunMessageView]:
+        pass
 
     async def list_events_by_run(
         self,
@@ -31,7 +33,8 @@ class RunEventLog(Protocol):
         run_id: RunId,
         *,
         limit: int = 500,
-    ) -> list[StoredRunEvent]: ...
+    ) -> list[StoredRunEvent]:
+        pass
 
 
 __all__ = [
diff --git a/backend/packages/harness/deerflow/runtime/runs/repositories/run_repository.py b/backend/packages/harness/deerflow/runtime/runs/repositories/run_repository.py
index 19d98fe34..6cfd44960 100644
--- a/backend/packages/harness/deerflow/runtime/runs/repositories/run_repository.py
+++ b/backend/packages/harness/deerflow/runtime/runs/repositories/run_repository.py
@@ -13,9 +13,11 @@ if TYPE_CHECKING:
 class RunRepository(Protocol):
     """Persistence boundary for run state snapshots."""
 
-    async def save(self, run: Run) -> None: ...
+    async def save(self, run: Run) -> None:
+        pass
 
-    async def get(self, run_id: RunId, *, user_id: UserId | None = None) -> Run | None: ...
+    async def get(self, run_id: RunId, *, user_id: UserId | None = None) -> Run | None:
+        pass
 
     async def list_by_thread(
         self,
@@ -23,9 +25,11 @@ class RunRepository(Protocol):
         *,
         user_id: UserId | None = None,
         limit: int = 100,
-    ) -> list[RunSnapshot]: ...
+    ) -> list[RunSnapshot]:
+        pass
 
-    async def delete(self, run_id: RunId) -> bool: ...
+    async def delete(self, run_id: RunId) -> bool:
+        pass
 
 
 __all__ = [
diff --git a/backend/packages/harness/deerflow/runtime/runs/streams/run_stream_broker.py b/backend/packages/harness/deerflow/runtime/runs/streams/run_stream_broker.py
index e34e1a57a..0229b3cac 100644
--- a/backend/packages/harness/deerflow/runtime/runs/streams/run_stream_broker.py
+++ b/backend/packages/harness/deerflow/runtime/runs/streams/run_stream_broker.py
@@ -19,9 +19,11 @@ class RunStreamEvent:
 class RunStreamBroker(Protocol):
     """Realtime publish/subscribe boundary for run streams."""
 
-    async def publish(self, run_id: RunId, event: str, data: Any) -> None: ...
+    async def publish(self, run_id: RunId, event: str, data: Any) -> None:
+        pass
 
-    async def publish_terminal(self, run_id: RunId, *, event: str = "end", data: Any = None) -> None: ...
+    async def publish_terminal(self, run_id: RunId, *, event: str = "end", data: Any = None) -> None:
+        pass
 
     def subscribe(
         self,
@@ -29,9 +31,11 @@ class RunStreamBroker(Protocol):
         *,
         last_event_id: str | None = None,
         heartbeat_interval: float = 15.0,
-    ) -> AsyncIterator[RunStreamEvent]: ...
+    ) -> AsyncIterator[RunStreamEvent]:
+        pass
 
-    async def cleanup(self, run_id: RunId, *, delay: float = 0) -> None: ...
+    async def cleanup(self, run_id: RunId, *, delay: float = 0) -> None:
+        pass
 
 
 __all__ = [