diff --git a/src/scheduler.py b/src/scheduler.py
index eb35208..8d93985 100644
--- a/src/scheduler.py
+++ b/src/scheduler.py
@@ -75,6 +75,7 @@ from src import (
     settings_config, task_create, work_graph_execute, work_graph_orchestrate, work_node_run,
 )
 
+# Rationale: see module docstring's "Threading model" section (lines 21-28) above.
 _BUSY_TIMEOUT_MS = 30000
 _FIX_LOOP_TIMEOUT = 1200