diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8893c671..d6612777 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -47,6 +47,11 @@ jobs:
       event_name: ${{ github.event_name }}
   tidy:
     uses: taiki-e/github-actions/.github/workflows/tidy.yml@main
+    permissions:
+      contents: read
+      pull-requests: write # for gh pr edit --add-assignee
+      repository-projects: read # for gh pr edit --add-assignee
+    secrets: inherit
 
   test:
     strategy:
diff --git a/tools/tidy.sh b/tools/tidy.sh
index 9119a998..aabf7b85 100755
--- a/tools/tidy.sh
+++ b/tools/tidy.sh
@@ -750,7 +750,9 @@ EOF
         if [[ -n "${dependencies_words}" ]]; then
             LC_ALL=C sort -f >>.github/.cspell/rust-dependencies.txt <<<"${dependencies_words}"$'\n'
         fi
-        check_diff .github/.cspell/rust-dependencies.txt
+        if [[ -z "${REMOVE_UNUSED_WORDS:-}" ]]; then
+            check_diff .github/.cspell/rust-dependencies.txt
+        fi
         if ! grep -Fq '.github/.cspell/rust-dependencies.txt linguist-generated' .gitattributes; then
             error "you may want to mark .github/.cspell/rust-dependencies.txt linguist-generated"
         fi