diff --git a/src/calng/FrameSelectionArbiter.py b/src/calng/FrameSelectionArbiter.py
index 079252af21b271016b763c10121afda1f3586b98..7522981f89836b08cba2c39e78911f76a42a7ca6 100644
--- a/src/calng/FrameSelectionArbiter.py
+++ b/src/calng/FrameSelectionArbiter.py
@@ -402,6 +402,7 @@ class AdvancedFrameSelectionArbiter(BaseFrameSelectionArbiter):
                 except Exception as ex:
                     warn(f"Kernel for {prefix} failed: {ex}")
                     res[selection_name] = np.ones(num_frames, dtype=bool)
+                out_hash[f"{selection_name}.mask"] = list(map(bool, res[selection_name]))
         return res
 
     def _configure_decision(self, decision_string):
@@ -480,6 +481,17 @@ class AdvancedFrameSelectionArbiter(BaseFrameSelectionArbiter):
                 kernel_class.extend_device_schema(
                     schema_update, kernel_prefix
                 )
+                (
+	            NODE_ELEMENT(output_schema_update)
+	            .key(selection_name)
+                    .commit(),
+
+                    VECTOR_BOOL_ELEMENT(output_schema_update)
+                    .key(f"{selection_name}.mask")
+                    .assignmentOptional()
+                    .defaultValue([])
+                    .commit(),
+                )
                 kernel_class.extend_output_schema(output_schema_update, selection_name)
                 new_selection_steps[selection_name] = (kernel_class, preselection)