diff --git a/temporalio/worker/_workflow.py b/temporalio/worker/_workflow.py
index 37d5ec16..c91e4e69 100644
--- a/temporalio/worker/_workflow.py
+++ b/temporalio/worker/_workflow.py
@@ -215,7 +215,7 @@ async def _handle_activation(
                     )
                 except asyncio.TimeoutError:
                     raise RuntimeError(
-                        f"Potential deadlock detected, workflow didn't yield within {self._deadlock_timeout_seconds} second(s)"
+                        f"[TMPRL1101] Potential deadlock detected, workflow didn't yield within {self._deadlock_timeout_seconds} second(s)"
                     )
         except Exception as err:
             logger.exception(