diff --git a/.github/workflows/run_tests.yaml b/.github/workflows/run_tests.yaml
index b58c18a..cfa4ee1 100644
--- a/.github/workflows/run_tests.yaml
+++ b/.github/workflows/run_tests.yaml
@@ -1,4 +1,8 @@
 name: Run benchmark tests
+
+# Declare default permissions as read only.
+permissions: read-all
+
 on:
   pull_request:
   push: