diff --git a/skills/apsuflow/SKILL.md b/skills/apsuflow/SKILL.md
index c0afd07..8ea3398 100644
--- a/skills/apsuflow/SKILL.md
+++ b/skills/apsuflow/SKILL.md
@@ -222,6 +222,9 @@ job backup {
 ```
 
 - Use markerless canonical syntax and let `fmt` normalize it.
+- `depends_on` is a startup-health gate: dependencies start first, and a
+  dependent waits until each is running/healthy. Running satisfies the gate
+  when no health probe is declared.
 - Prefer digest-pinned production images.
 - Reference secret names and set values with `apsuflow secret set`; never embed
   secret values in `.apsu`.