diff --git a/.github/workflows/gem-build.yml b/.github/workflows/gem-build.yml
index c10fd4fcc4..b59c437770 100644
--- a/.github/workflows/gem-build.yml
+++ b/.github/workflows/gem-build.yml
@@ -1,8 +1,10 @@
 name: Type-on-strap CI
 
 on:
-  pull_request:
-    branches: [ master ]
+  workflow_run:
+    workflows: ["Build with Docker"]
+    types:
+      - completed
 
 jobs:
   ruby: