diff --git a/src/check-standard.sh b/src/check-standard.sh
index dff1249..0f9dc55 100755
--- a/src/check-standard.sh
+++ b/src/check-standard.sh
@@ -18,6 +18,7 @@ export LC_ALL=C
 MAX_BYTES=$((5 * 1024 * 1024))
 # Besides letters, digits and . _ - this allows the route symbols frameworks put in file names:
 # [slug] (group) @slot +page $param {-$optional}.
+# shellcheck disable=SC2016  # the $ is a literal character here, not an expansion
 NAME_RE='^[][A-Za-z0-9._@+()${}-]+$'
 KEBAB_RE='^[a-z0-9]+(-[a-z0-9]+)*(\.[a-z0-9]+)*$'
 TITLE_RE='^(feat|fix|docs|chore|refactor|test|perf|ci|build|style|revert)(\([a-z0-9._/-]+\))?!?: [^ ]'
@@ -74,6 +75,7 @@ kebab_of() { # suggested kebab-case spelling of a name
 
 # --- exceptions ---------------------------------------------------------------------------
 
+# shellcheck disable=SC2094  # report only names the file in a message; it never writes to it
 load_exceptions() {
   [ -f "$EXCEPTIONS_FILE" ] || return 0
   local line pattern reason n=0
@@ -141,7 +143,7 @@ set_kind() { # NAME — sets $kind for file types with their own rule, or emptie
 }
 
 check_path() { # PATH — name and file-type rules for one repository-relative path
-  local path=$1 rest=$1 comp first= depth=0
+  local path=$1 rest=$1 comp first='' depth=0
   is_excepted "$path" && return 0
   while :; do
     comp=${rest%%/*}
@@ -304,7 +306,7 @@ run_staged() {
 }
 
 run_hook() { # blocks Claude Code from creating a file whose name breaks the standard
-  local input file_path script_dir root_l root_p rel cur rest comp match
+  local input file_path script_dir root_l root_p rel cur rest comp match entry
   input=$(cat)
   if ! command -v jq >/dev/null 2>&1; then
     echo "check-standard: jq is not installed, so the file-name check was skipped." >&2
@@ -332,7 +334,14 @@ run_hook() { # blocks Claude Code from creating a file whose name breaks the sta
   rest=$rel
   while [ "$errors" -eq 0 ]; do   # a new name must not clash by letter case with an existing one
     comp=${rest%%/*}
-    match=$(ls -A "$cur" 2>/dev/null | grep -ixF -- "$comp" | grep -vxF -- "$comp" | head -n 1)
+    match=
+    shopt -s nocasematch
+    for entry in "$cur"/* "$cur"/.[!.]* "$cur"/..?*; do
+      [ -e "$entry" ] || continue
+      entry=${entry##*/}
+      if [ "$entry" != "$comp" ] && [[ $entry == "$comp" ]]; then match=$entry; break; fi
+    done
+    shopt -u nocasematch
     if [ -n "$match" ]; then
       report error "$rel" "\"$comp\" differs only by letter case from the existing \"$match\". Use \"$match\"."
       break
diff --git a/tests/check-standard.test.sh b/tests/check-standard.test.sh
index 4bf4109..396fc66 100755
--- a/tests/check-standard.test.sh
+++ b/tests/check-standard.test.sh
@@ -75,7 +75,7 @@ expect_clean() {
 
 echo "== whole repository =="
 new_repo; run; expect_clean "clean repository passes"
-cd "$TMP"; run; expect "outside a git repository fails" 1 "git repository"
+cd "$TMP" || exit 1; run; expect "outside a git repository fails" 1 "git repository"
 
 new_repo; rm README.md; run; expect "missing README.md fails" 1 "README.md"
 new_repo; printf '# no import\n' > CLAUDE.md; run; expect "CLAUDE.md without @AGENTS.md fails" 1 "@AGENTS.md"
@@ -98,6 +98,7 @@ touch "src/app/[slug]/page.tsx" "src/app/(marketing)/page.tsx" "src/app/@modal/d
   src/adlete3d/body/__init__.py src/components/Button.tsx
 run; expect_clean "framework names inside src pass"
 new_repo; mkdir -p "src/routes/{-\$locale}"
+# shellcheck disable=SC2016  # literal $ in TanStack Router file names
 touch 'src/routes/$username.tsx' 'src/routes/{-$locale}/index.tsx' src/routes/__root.tsx
 run; expect_clean "TanStack Router names inside src pass"
 new_repo; blob=$(git hash-object -w /dev/null)
@@ -160,7 +161,7 @@ new_repo; touch "docs/old notes.md"; git add -A; git_q commit -qm legacy
 echo change >> "docs/old notes.md"; git add -A; run --staged; expect_clean "editing a legacy file does not block the commit"
 new_repo; head -c 6000000 /dev/zero > src/model.bin; git add -A; run --staged; expect "file over 5 MB blocks the commit" 1 "src/model.bin"
 new_repo; mkdir tasks; touch tasks/todo.md; git add -A; run --staged; expect "new unknown top-level folder warns but passes" 0 "tasks/"
-dir=$(mktemp -d "$TMP/empty.XXXXXX"); cd "$dir"; git init -q -b main; touch "Bad Name.md"; git add -A
+dir=$(mktemp -d "$TMP/empty.XXXXXX"); cd "$dir" || exit 1; git init -q -b main; touch "Bad Name.md"; git add -A
 run --staged; expect "first commit of an empty repository is checked" 1 "Bad Name.md"
 
 echo "== Claude Code hook =="