diff --git a/packages/zoe/package.json b/packages/zoe/package.json
index 52c2384262a..79d462d8768 100644
--- a/packages/zoe/package.json
+++ b/packages/zoe/package.json
@@ -56,7 +56,8 @@
     "@agoric/swingset-vat": "^0.10.0",
     "ava": "^3.12.1",
     "esm": "^3.2.25",
-    "nyc": "^15.1.0"
+    "nyc": "^15.1.0",
+    "ses": "^0.11.0"
   },
   "files": [
     "src/",
@@ -111,6 +112,15 @@
       "no-unused-expressions": "off",
       "no-loop-func": "off",
       "no-inner-declarations": "off",
+      "import/no-extraneous-dependencies": [
+        "error",
+        {
+          "devDependencies": [
+            "test/**/*.js",
+            "scripts/**/*.js"
+          ]
+        }
+      ],
       "import/prefer-default-export": "off",
       "jsdoc/no-undefined-types": "off",
       "jsdoc/require-jsdoc": "off",
diff --git a/packages/zoe/scripts/build-zcfBundle.js b/packages/zoe/scripts/build-zcfBundle.js
index d4a4141cb51..bba7b8a7d22 100644
--- a/packages/zoe/scripts/build-zcfBundle.js
+++ b/packages/zoe/scripts/build-zcfBundle.js
@@ -1,3 +1,4 @@
+import 'ses';
 import fs from 'fs';
 import process from 'process';
 import bundleSource from '@agoric/bundle-source';