diff --git a/packages/zone/durable.js b/packages/zone/durable.js
index cabf929916f..449ab5300d2 100644
--- a/packages/zone/durable.js
+++ b/packages/zone/durable.js
@@ -1 +1,3 @@
+// @jessie-check
+
 export * from './src/durable.js';
diff --git a/packages/zone/heap.js b/packages/zone/heap.js
index deb751bdf4f..16c192a7bca 100644
--- a/packages/zone/heap.js
+++ b/packages/zone/heap.js
@@ -1 +1,3 @@
+// @jessie-check
+
 export * from './src/heap.js';
diff --git a/packages/zone/src/durable.js b/packages/zone/src/durable.js
index aa484f26017..3ace1c7b5c1 100644
--- a/packages/zone/src/durable.js
+++ b/packages/zone/src/durable.js
@@ -1,3 +1,5 @@
+// @jessie-check
+
 import {
   canBeDurable,
   makeScalarMapStore,
diff --git a/packages/zone/src/heap.js b/packages/zone/src/heap.js
index 204866956e3..2f32e1692d8 100644
--- a/packages/zone/src/heap.js
+++ b/packages/zone/src/heap.js
@@ -1,3 +1,5 @@
+// @jessie-check
+
 import {
   makeExo,
   defineExoClass,
diff --git a/packages/zone/src/index.js b/packages/zone/src/index.js
index ebed4fee707..d316d08870d 100644
--- a/packages/zone/src/index.js
+++ b/packages/zone/src/index.js
@@ -1,3 +1,5 @@
+// @jessie-check
+
 import { makeExo, defineExoClass, defineExoClassKit } from '@agoric/store';
 
 export * from './heap.js';
diff --git a/packages/zone/src/virtual.js b/packages/zone/src/virtual.js
index fea6a47d95d..e4262588eda 100644
--- a/packages/zone/src/virtual.js
+++ b/packages/zone/src/virtual.js
@@ -1,3 +1,5 @@
+// @jessie-check
+
 import {
   canBeDurable,
   defineVirtualExoClass,
diff --git a/packages/zone/virtual.js b/packages/zone/virtual.js
index a635f7d39bd..a8685d57319 100644
--- a/packages/zone/virtual.js
+++ b/packages/zone/virtual.js
@@ -1 +1,3 @@
+// @jessie-check
+
 export * from './src/virtual.js';