diff --git a/src/operation/scripting.md b/src/operation/scripting.md
index 2a309e7..56ab1e6 100644
--- a/src/operation/scripting.md
+++ b/src/operation/scripting.md
@@ -154,7 +154,8 @@ denoted by the active target register, where *pat* is the [dataspace
 pattern](../glossary.md#dataspace-pattern) resulting from evaluation of *PatternExpr*, and
 *ref* is a fresh [entity](../glossary.md#entity) whose behaviour is to execute *Instruction* in
 response to assertions (resp. messages) carrying captured values from the binding-patterns in
-*pat*.
+*pat*. When the active target denotes a [dataspace](../glossary.md#dataspace) entity, the
+`Observe` record establishes a subscription to matching assertions and messages.
 
 Each time a matching assertion arrives at a *ref*, a new [facet](../glossary.md#facet) is
 created, and *Instruction* is executed in the new facet. If the instruction creating the facet