diff --git a/CLAUDE.md b/CLAUDE.md
index 9af2700..2142076 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -10,6 +10,7 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 Key features:
 - Generate modular LangGraph project structures via `act new`
 - Add new graph components ("Casts") via `act cast`
+- Upgrade skills to the latest version via `act upgrade`
 - Multi-language template support (English/Korean)
 - Built-in Claude Code skills for architecture, development, and testing
 
@@ -25,6 +26,7 @@ uv sync
 # Run CLI directly
 uv run act new              # Create new Act project
 uv run act cast             # Add Cast to existing project
+uv run act upgrade          # Upgrade skills in existing project
 
 # Run tests (ignores scaffold templates)
 uv run pytest
@@ -51,7 +53,7 @@ act-operator/
 │   └── act_operator/               # Source code
 │       ├── __init__.py             # Version: __version__
 │       ├── __main__.py             # Entry point
-│       ├── cli.py                  # Typer CLI commands (new, cast)
+│       ├── cli.py                  # Typer CLI commands (new, cast, upgrade)
 │       ├── utils.py                # Name normalization, cookiecutter rendering
 │       ├── version.py              # Version utilities
 │       ├── scaffold/               # Cookiecutter template
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c2d8534..7bb7066 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -50,6 +50,9 @@ uv sync
 # Run CLI locally
 uv run act new --path ./test-act --act-name "Test" --cast-name "Main"
 
+# Upgrade skills in an existing project
+uv run act upgrade --path ./test-act
+
 # Run tests (when available)
 uv run pytest
 ```
@@ -96,7 +99,7 @@ The Act Operator project consists of several components.
 **Location**: `act_operator/`
 
 **Includes**:
-- CLI commands (`act new`, `act cast`)
+- CLI commands (`act new`, `act cast`, `act upgrade`)
 - cookiecutter scaffold generation logic
 - Build/deployment processes
 
diff --git a/CONTRIBUTING_KR.md b/CONTRIBUTING_KR.md
index e8eb303..6b2991a 100644
--- a/CONTRIBUTING_KR.md
+++ b/CONTRIBUTING_KR.md
@@ -50,6 +50,9 @@ uv sync
 # 로컬에서 CLI 실행
 uv run act new --path ./test-act --act-name "Test" --cast-name "Main"
 
+# 기존 프로젝트의 스킬 업그레이드
+uv run act upgrade --path ./test-act
+
 # 테스트 실행 시
 uv run pytest
 ```
@@ -96,7 +99,7 @@ Act Operator 프로젝트는 여러 컴포넌트로 구성되어 있습니다.
 **위치**: `act_operator/`
 
 **포함 내용**:
-- CLI 명령어 (`act new`, `act cast`)
+- CLI 명령어 (`act new`, `act cast`, `act upgrade`)
 - cookiecutter 스캐폴드 생성 로직
 - 빌드/배포 프로세스
 
diff --git a/README.md b/README.md
index e0177ad..a6649de 100644
--- a/README.md
+++ b/README.md
@@ -378,11 +378,33 @@ act new [OPTIONS]
   --act-name TEXT       Project name
   --cast-name TEXT      Initial cast name
   --path PATH           Target directory
+  --lang TEXT           Language for scaffolded docs (en|kr)
 
 # Add cast to existing project
 act cast [OPTIONS]
   --cast-name TEXT      Cast name
   --path PATH           Act project directory
+  --lang TEXT           Language for scaffolded cast docs (en|kr)
+
+# Upgrade skills in an existing Act project
+act upgrade [OPTIONS]
+  --path PATH           Act project directory (default: current directory)
+```
+
+### `act upgrade`
+
+Updates `.claude/skills/` in an existing Act project to the latest version bundled with Act Operator. This is useful when a new version of Act Operator ships improved or additional skills.
+
+- Auto-detects the project language (English/Korean) from `README.md`
+- Auto-detects the first Cast from `langgraph.json`
+- Backs up existing skills to `.claude/skills.bak/` before replacing
+
+```bash
+# Upgrade skills in the current directory
+act upgrade
+
+# Upgrade skills in a specific project
+act upgrade --path ./my-act-project
 ```
 
 After scaffolding, see `TEMPLATE_README.md` in your generated project for detailed usage — dependency management, development server, graph registry configuration, and more.
diff --git a/README_KR.md b/README_KR.md
index 9328218..01f6136 100644
--- a/README_KR.md
+++ b/README_KR.md
@@ -378,11 +378,33 @@ act new [OPTIONS]
   --act-name TEXT       프로젝트 이름
   --cast-name TEXT      초기 Cast 이름
   --path PATH           대상 디렉토리
+  --lang TEXT           스캐폴드 문서 언어 (en|kr)
 
 # 기존 프로젝트에 Cast 추가
 act cast [OPTIONS]
   --cast-name TEXT      Cast 이름
   --path PATH           Act 프로젝트 디렉토리
+  --lang TEXT           스캐폴드 Cast 문서 언어 (en|kr)
+
+# 기존 Act 프로젝트의 스킬 업그레이드
+act upgrade [OPTIONS]
+  --path PATH           Act 프로젝트 디렉토리 (기본값: 현재 디렉토리)
+```
+
+### `act upgrade`
+
+기존 Act 프로젝트의 `.claude/skills/`를 Act Operator에 번들된 최신 버전으로 업데이트합니다. Act Operator의 새 버전에 개선된 스킬이나 추가 스킬이 포함될 때 유용합니다.
+
+- `README.md`에서 프로젝트 언어(영어/한국어)를 자동 감지
+- `langgraph.json`에서 첫 번째 Cast를 자동 감지
+- 교체 전 기존 스킬을 `.claude/skills.bak/`에 백업
+
+```bash
+# 현재 디렉토리의 스킬 업그레이드
+act upgrade
+
+# 특정 프로젝트의 스킬 업그레이드
+act upgrade --path ./my-act-project
 ```
 
 스캐폴딩 후 자세한 사용법 — 의존성 관리, 개발 서버, 그래프 레지스트리 설정 등 — 은 생성된 프로젝트 내 `TEMPLATE_README.md`를 참조하세요.
diff --git a/act_operator/act_operator/__init__.py b/act_operator/act_operator/__init__.py
index 906d362..43c4ab0 100644
--- a/act_operator/act_operator/__init__.py
+++ b/act_operator/act_operator/__init__.py
@@ -1 +1 @@
-__version__ = "0.6.0"
+__version__ = "0.6.1"
diff --git a/act_operator/act_operator/scaffold/{{ cookiecutter.act_slug }}/pyproject.toml b/act_operator/act_operator/scaffold/{{ cookiecutter.act_slug }}/pyproject.toml
index cafd63c..a350c60 100644
--- a/act_operator/act_operator/scaffold/{{ cookiecutter.act_slug }}/pyproject.toml	
+++ b/act_operator/act_operator/scaffold/{{ cookiecutter.act_slug }}/pyproject.toml	
@@ -19,7 +19,7 @@ lint = [
     "ruff",
 ]
 dev = [
-    "act-operator>=0.3.0",
+    "act-operator>=0.6.0",
     {include-group = "test"},
     {include-group = "lint"},
 ]