diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4cc49139..b3a62925 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -3,22 +3,12 @@ name: CI
 on:
   push:
     branches: [master]
-    paths-ignore:
-      - "docs/**"
-      - "*.md"
   pull_request:
     branches: [master]
-    paths-ignore:
-      - "docs/**"
-      - "*.md"
 
 permissions:
   contents: read
 
-concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
-  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
-
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/.jules/sentinel.md b/.jules/sentinel.md
index a885865d..967a7ab6 100644
--- a/.jules/sentinel.md
+++ b/.jules/sentinel.md
@@ -99,3 +99,7 @@
 **Root cause:** The protected implementation added canonical names to the exclusion set but did not compare each observed directory entry through a locale-stable normalized key.
 **Prevention:** Build one `Locale.ROOT` lowercase set from the canonical sensitive names, compare every observed name against it, and add the original spelling to the exclusion set so downstream exact membership remains correct.
 **Evidence:** `testProcessIgnoreFileTreatsSensitiveNamesCaseInsensitively` failed on test-only commit `472b916cd40f70693c4e1eb48956042a25353feb` (CI run `31469596932`) and passed with the source fix at `bb113d858ccfc42ddaecf6729749b238e5ade2d0` (CI run `31469921661`).
+## 2024-09-01 - Input Validation for Path Length
+**Vulnerability:** Path inputs without length limitations can lead to Out-Of-Memory (OOM) or Denial of Service (DoS) when processed.
+**Learning:** Always explicitly validate unbounded input strings (e.g., path lengths) against a reasonable limit (e.g., 4096) before processing or relying on them in file system APIs.
+**Prevention:** Add explicit `require(length <= LIMIT)` checks on input parameters at the boundary entry points (like `go()`).
diff --git a/src/main/kotlin/html4tree/main.kt b/src/main/kotlin/html4tree/main.kt
index 0972fa2c..93950c39 100644
--- a/src/main/kotlin/html4tree/main.kt
+++ b/src/main/kotlin/html4tree/main.kt
@@ -136,6 +136,7 @@ internal fun read_file_identity(file: File): FileIdentity {
 
 fun go(topDir: String, maxLevel: Int)  {
     require(topDir.isNotBlank())
+    require(topDir.length <= 4096) { "Directory path is too long" }
     require(!topDir.contains("..")) { "Path traversal sequences are not allowed." }
     // 보안 수정: symlink 검사를 우회하는 canonicalFile 대신 absoluteFile을 사용
     // canonicalFile은 symlink를 대상 경로로 해석하여 이어지는 NOFOLLOW_LINKS 검사를 무력화합니다.
diff --git a/src/test/kotlin/html4tree/MainTest.kt b/src/test/kotlin/html4tree/MainTest.kt
index 5b76cc5d..f444daf1 100644
--- a/src/test/kotlin/html4tree/MainTest.kt
+++ b/src/test/kotlin/html4tree/MainTest.kt
@@ -127,6 +127,15 @@ class MainTest {
         }
     }
 
+    @Test
+    fun testGoRejectsExcessivelyLongPaths() {
+        val longPath = "a".repeat(4097)
+        val exception = assertFailsWith<IllegalArgumentException> {
+            go(longPath, -1)
+        }
+        assertEquals("Directory path is too long", exception.message)
+    }
+
     @Test
     fun testGoIgnoresHiddenFilesAndDirectories() {
         val hiddenFile = File(tempDir, ".hidden_file.txt")