diff --git a/.gitlab-ci/commitrules.yml b/.gitlab-ci/commitrules.yml
index ef7d0805..a3913a98 100644
--- a/.gitlab-ci/commitrules.yml
+++ b/.gitlab-ci/commitrules.yml
@@ -2,3 +2,12 @@ patterns:
   deny:
     - regex: '^$CI_MERGE_REQUEST_PROJECT_URL/(-/)?merge_requests/$CI_MERGE_REQUEST_IID$'
       message: Commit message must not contain a link to its own merge request
+    - regex: '^extensions/'
+      message: Commit message subject should not be prefixed with 'extensions/', use the extension name instead
+      where: subject
+    - regex: '^[^:]+: [a-z]'
+      message: "Commit message subject should be properly Capitalized. E.g.  'window: Marginalize extradicity'"
+      where: subject
+    - regex: '^\S*\.js:'
+      message: Commit message subject prefix should not include .js
+      where: subject