diff --git a/.github/workflows/grpc-tools-build.yml b/.github/workflows/grpc-tools-build.yml
index f32a688c..64ee8121 100644
--- a/.github/workflows/grpc-tools-build.yml
+++ b/.github/workflows/grpc-tools-build.yml
@@ -8,6 +8,9 @@ on:
     branches:
       - master
 
+permissions:
+  contents: read #  to fetch code (actions/checkout)
+
 jobs:
   linux_build:
     name: Linux grpc-tools Build