diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 0000000..5ec706f
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,3 @@
+## 2024-06-05 - Avoid statSync in filesystem traversal
+**Learning:** In local-first CLI applications that heavily rely on file system traversal, using `readdirSync` followed by `statSync` creates a severe performance bottleneck due to excessive I/O operations.
+**Action:** Always use `readdirSync(path, { withFileTypes: true })` to retrieve `fs.Dirent` objects which provide `.isDirectory()` without additional I/O overhead.
diff --git a/src/files.ts b/src/files.ts
index b1e1e43..a499108 100644
--- a/src/files.ts
+++ b/src/files.ts
@@ -1,4 +1,4 @@
-import { existsSync, readdirSync, readFileSync, statSync } from "node:fs";
+import { existsSync, readdirSync, readFileSync } from "node:fs";
 import { basename, dirname, join, relative, resolve } from "node:path";
 
 export type VspecConfig = { vspec_format: 1; key_prefix: string; spec_language?: "ko" | "en" | "match-input" };
@@ -27,10 +27,11 @@ export function projectKey(start = process.cwd()): string | null {
 export function walkFiles(root: string, predicate: (path: string) => boolean): string[] {
   if (!existsSync(root)) return [];
   const files: string[] = [];
-  for (const entry of readdirSync(root)) {
-    const path = join(root, entry);
-    const stat = statSync(path);
-    if (stat.isDirectory()) files.push(...walkFiles(path, predicate));
+  // ⚡ Bolt: Use withFileTypes to avoid separate statSync calls, which significantly reduces I/O overhead
+  // when traversing large directories.
+  for (const entry of readdirSync(root, { withFileTypes: true })) {
+    const path = join(root, entry.name);
+    if (entry.isDirectory()) files.push(...walkFiles(path, predicate));
     else if (predicate(path)) files.push(path);
   }
   return files.sort();