diff --git a/src/scripts/merge_tools/gitmerge.sh b/src/scripts/merge_tools/gitmerge.sh
index 0949f1d409..d32e741299 100755
--- a/src/scripts/merge_tools/gitmerge.sh
+++ b/src/scripts/merge_tools/gitmerge.sh
@@ -24,7 +24,8 @@ git_strategy=$4
 cd "$clone_dir" || (echo "$0: cannot cd to $clone_dir" ; exit 1)
 
 git checkout "$branch1" --force
-git config merge.conflictstyle zdiff3
+git config --local merge.conflictstyle zdiff3
+git config --local mergetool.prompt false
 
 echo "Running: git merge --no-edit $git_strategy $branch2"
 # shellcheck disable=SC2086