diff --git a/.github/workflows/tox.yml b/.github/workflows/tox.yml
index 3fff70b..fda49e5 100644
--- a/.github/workflows/tox.yml
+++ b/.github/workflows/tox.yml
@@ -4,6 +4,9 @@ on:
   - push
   - pull_request
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ${{ matrix.platform }}