`khatus_actuate_alert_to_notify_send` actuator:
![screenshot-self-error-propagation](screenshot-self-error-propagation.jpg)
+
+TODO
+----
+
+- retry/cache for sensors fetching flaky remote resources (such as weather)
+- throttling of broken sensors (constantly returns errors)
+- alert specification language
+ - trigger threshold
+ - above/bellow/equal to threshold value
+ - priority
+ - snooze time (if already alerted, when to re-alert?)
+ - text: subject/body
+- more-structured controller API: a sensor submits a list of k/v pairs
+
+Redesign notes
+--------------
+
+- controller should not do formatting
+- need in-memory db for diskless feedback/throttling and cache