diff --git a/spec.html b/spec.html
index aa6a0c320cf..4bc4ddf5508 100644
--- a/spec.html
+++ b/spec.html
@@ -21880,6 +21880,7 @@ <h1>Evaluate ( ) Concrete Method</h1>
           <p>This abstract method performs the following steps (most of the work is done by the auxiliary function InnerModuleEvaluation):</p>
 
           <emu-alg>
+            1. Assert: This call to Evaluate is not happening at the same time as another call to Evaluate within the surrounding agent.
             1. Let _module_ be this Cyclic Module Record.
             1. Assert: _module_.[[Status]] is `"linked"` or `"evaluated"`.
             1. Let _stack_ be a new empty List.