diff --git a/letta/schemas/run.py b/letta/schemas/run.py
index a03cd49d..c029281f 100644
--- a/letta/schemas/run.py
+++ b/letta/schemas/run.py
@@ -65,4 +65,5 @@ class RunUpdate(RunBase):
     completed_at: Optional[datetime] = Field(None, description="The timestamp when the run was completed.")
     stop_reason: Optional[StopReasonType] = Field(None, description="The reason why the run was stopped.")
     metadata: Optional[dict] = Field(None, validation_alias="metadata_", description="Additional metadata for the run.")
+    total_duration_ns: Optional[int] = Field(None, description="Total run duration in nanoseconds")
     model_config = ConfigDict(extra="ignore")  # Ignores extra fields
diff --git a/letta/services/run_manager.py b/letta/services/run_manager.py
index 44838536..c45b97db 100644
--- a/letta/services/run_manager.py
+++ b/letta/services/run_manager.py
@@ -206,11 +206,16 @@ class RunManager:
         async with db_registry.async_session() as session:
             metrics = await RunMetricsModel.read_async(db_session=session, identifier=run_id, actor=actor)
             # Calculate runtime if run is completing
-            if is_terminal_update and metrics.run_start_ns:
-                import time
+            if is_terminal_update:
+                # Use total_duration_ns from RunUpdate if provided
+                # Otherwise fall back to system time
+                if update.total_duration_ns is not None:
+                    metrics.run_ns = update.total_duration_ns
+                elif metrics.run_start_ns:
+                    import time
 
-                current_ns = int(time.time() * 1e9)
-                metrics.run_ns = current_ns - metrics.run_start_ns
+                    current_ns = int(time.time() * 1e9)
+                    metrics.run_ns = current_ns - metrics.run_start_ns
             metrics.num_steps = num_steps
             await metrics.update_async(db_session=session, actor=actor, no_commit=True, no_refresh=True)
             await session.commit()