diff --git a/packages/@aws-cdk/cfnspec/build-tools/create-missing-libraries.ts b/packages/@aws-cdk/cfnspec/build-tools/create-missing-libraries.ts
index 444a51f739515..8b0e00fa15582 100644
--- a/packages/@aws-cdk/cfnspec/build-tools/create-missing-libraries.ts
+++ b/packages/@aws-cdk/cfnspec/build-tools/create-missing-libraries.ts
@@ -241,6 +241,9 @@ async function main() {
       '',
       '.eslintrc.js',
       'jest.config.js',
+      '',
+      '# exclude cdk artifacts',
+      '**/cdk.out',
       'junit.xml',
       'test/',
     ]);