diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b3b4e7b..4ec2747 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,6 +6,9 @@ on:
   pull_request:
     branches: [main]
 
+permissions:
+  contents: read
+
 jobs:
   test:
     name: Test (Python ${{ matrix.python-version }}, ${{ matrix.os }})