diff --git a/tools/diff-processor/README.md b/tools/diff-processor/README.md
index fdc47c8f9731..26214e44d5ba 100644
--- a/tools/diff-processor/README.md
+++ b/tools/diff-processor/README.md
@@ -13,7 +13,7 @@ make build OLD_REF=branch_or_commit NEW_REF=branch_or_commit
 
 # Run the commands
 bin/diff-processor breaking-changes
-bin/diff-processor add-labels PR_ID [--dry-run]
+GITHUB_TOKEN=github_token bin/diff-processor add-labels PR_ID [--dry-run]  # Requires write access to issues
 ```
 
 ## Test