diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index d79359d27d..0cea86d1da 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -6,6 +6,9 @@ on:
 env:
   MDBOOK_VERSION: 0.5.2
 
+permissions:
+  contents: read
+
 jobs:
   code-tests:
     runs-on: ubuntu-latest