diff --git a/.github/workflows/docker-publish.yml b/.github/workflows/docker-publish.yml
index 0e00d99..64a2b39 100644
--- a/.github/workflows/docker-publish.yml
+++ b/.github/workflows/docker-publish.yml
@@ -101,6 +101,9 @@ jobs:
           labels: ${{ steps.meta.outputs.labels }}
           cache-from: type=gha
           cache-to: type=gha,mode=max
+          # gh extension install의 비인증 API rate limit 회피용 (이미지 레이어에는 남지 않음)
+          secrets: |
+            gh_token=${{ secrets.GITHUB_TOKEN }}
 
       # Sign the resulting Docker image digest except on PRs.
       # This will only write to the public Rekor transparency log when the Docker
diff --git a/CLAUDE.md b/CLAUDE.md
index e7558db..9a1172d 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -12,6 +12,7 @@ This is a Docker base image for Coder workspaces, built on top of `codercom/ente
 - Docker with coder user in docker group
 - Homebrew package manager
 - Graphite CLI for stacked PRs
+- GitHub CLI extensions: `gh stack` (github/gh-stack) and `gh actions-lock` (github/gh-actions-lock)
 - AWS CLI, Google Cloud CLI, and Qodana CLI
 - Orca headless server (`orca-server` wrapper; launch via Coder template startup script)
 - Custom Nerd Fonts for terminal display
@@ -52,7 +53,7 @@ The repository uses a two-phase Docker build with clear separation between root
 
 **Build Phases:**
 - **Phase 1 (Root)**: System packages, CLI tools (gh, gcloud), fonts, Docker, root-level tools
-- **Phase 2 (Coder User)**: Development SDKs, Zimfw modules + Powerlevel10k prompt, Homebrew, Graphite CLI
+- **Phase 2 (Coder User)**: Development SDKs, Zimfw modules + Powerlevel10k prompt, Homebrew, Graphite CLI, GitHub CLI extensions
 
 **For detailed build phases, script organization, and configuration files, see [images/CLAUDE.md](images/CLAUDE.md)**
 
diff --git a/README.md b/README.md
index 2150397..f2f903d 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,7 @@ A comprehensive Docker base image for [Coder](https://coder.com/) workspaces, bu
 - **Docker**: Containerization with coder user in docker group
 - **Homebrew**: Package manager for Linux
 - **Graphite CLI**: Stacked pull request workflow
+- **GitHub CLI extensions**: `gh stack` (native stacked PRs) and `gh actions-lock` (lock and verify GitHub Actions dependencies)
 - **GitHub CLI (gh)**: GitHub operations from terminal
 - **AWS CLI**: Amazon Web Services command line interface
 - **Qodana CLI**: JetBrains code quality platform
@@ -105,6 +106,7 @@ All installation scripts are located in the `scripts/` directory:
 | `install-prompt.sh` | Zimfw modules (`.zimrc`), Powerlevel10k prompt, Orca history | coder |
 | `install-brew.sh` | Homebrew package manager | coder |
 | `install-graphite.sh` | Graphite CLI | coder |
+| `install-gh-extensions.sh` | GitHub CLI extensions (gh-stack, gh-actions-lock) | coder |
 
 ## Customization
 
diff --git a/images/CLAUDE.md b/images/CLAUDE.md
index b53ca75..1e21a38 100644
--- a/images/CLAUDE.md
+++ b/images/CLAUDE.md
@@ -20,7 +20,8 @@ images/
         ├── install-sdk.sh         # 사용자 개발 도구 (mise 글로벌 런타임, Claude Code)
         ├── install-prompt.sh      # Zimfw 모듈 + Powerlevel10k 프롬프트
         ├── install-brew.sh        # Homebrew 패키지 매니저
-        └── install-graphite.sh    # Graphite CLI (스택 PR)
+        ├── install-graphite.sh    # Graphite CLI (스택 PR)
+        └── install-gh-extensions.sh # GitHub CLI 확장 (gh-stack, gh-actions-lock)
 ```
 
 ## base/ 이미지
@@ -53,6 +54,7 @@ images/
 **기타:**
 - Homebrew 패키지 매니저
 - Graphite CLI (스택 PR 관리)
+- GitHub CLI 확장: `gh stack`(GitHub 네이티브 stacked PR), `gh actions-lock`(Actions 의존성 lock·검증)
 - 커스텀 Nerd Fonts (MesloLGS NF, JetBrainsMono, D2Coding)
 - Qodana CLI
 
@@ -238,6 +240,17 @@ Graphite CLI 설치:
 - 스택 PR 관리 도구
 - **중요**: mise가 관리하는 node(`install-sdk.sh`)가 먼저 설치되어야 함 (shims로 npm 사용)
 
+#### install-gh-extensions.sh (Coder User)
+
+GitHub CLI 확장 설치:
+- `gh extension install github/gh-stack`, `gh extension install github/gh-actions-lock`
+- 설치 위치: `~/.local/share/gh/extensions/`
+- 공개 저장소라 인증 없이 설치되지만, 비인증 API rate limit(IP당 시간당 60회)을 피하려고
+  CI는 `GITHUB_TOKEN`을 BuildKit secret(`gh_token`)으로 넘긴다. secret은 해당 `RUN`에만
+  마운트되고 이미지 레이어에는 남지 않는다. 로컬 빌드에서는 생략해도 된다
+  (`docker build --secret id=gh_token,env=GH_TOKEN ...`로 넘길 수도 있다)
+- `gh extension list`는 인증이 필요하므로 설치 확인은 각 확장을 직접 실행해서 한다
+
 ## 중요 사항
 
 ### 실행 순서
@@ -259,7 +272,8 @@ Graphite CLI 설치:
 1. SDK (`install-sdk.sh`) - mise 글로벌 런타임(node/bun/deno/java), npm 전역 패키지, Claude Code
 2. 프롬프트 (`install-prompt.sh`) - Zimfw 설치 이후
 3. Graphite (`install-graphite.sh`) - mise node(npm) 필요
-4. Homebrew
+4. GitHub CLI 확장 (`install-gh-extensions.sh`) - root 단계의 GitHub CLI 필요
+5. Homebrew
 
 ### 사용자 컨텍스트
 
diff --git a/images/base/Dockerfile b/images/base/Dockerfile
index 258fee1..810fbbf 100644
--- a/images/base/Dockerfile
+++ b/images/base/Dockerfile
@@ -137,6 +137,14 @@ RUN chmod +x /tmp/install-graphite.sh && \
     /bin/bash /tmp/install-graphite.sh && \
     rm /tmp/install-graphite.sh
 
+# GitHub CLI 확장 설치 (gh-stack, gh-actions-lock)
+# gh_token secret은 선택 사항 — 없으면 비인증으로 설치한다
+COPY --chown=coder:coder scripts/install-gh-extensions.sh /tmp/install-gh-extensions.sh
+RUN --mount=type=secret,id=gh_token,mode=0444 \
+    chmod +x /tmp/install-gh-extensions.sh && \
+    /bin/bash /tmp/install-gh-extensions.sh && \
+    rm /tmp/install-gh-extensions.sh
+
 # Homebrew 설치
 RUN /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
 
diff --git a/images/base/scripts/install-gh-extensions.sh b/images/base/scripts/install-gh-extensions.sh
new file mode 100755
index 0000000..a01f0a1
--- /dev/null
+++ b/images/base/scripts/install-gh-extensions.sh
@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+set -e
+
+echo "🧩 Installing GitHub CLI extensions..."
+
+# gh는 root 단계의 apt 설치에 의존한다 — 없으면 원인을 바로 알리고 중단한다
+if ! command -v gh &> /dev/null; then
+    echo "❌ GitHub CLI (gh) not found; the root-phase GitHub CLI install must run first" >&2
+    exit 1
+fi
+
+# 공개 저장소의 확장은 인증 없이 설치되지만, 비인증 API는 IP당 시간당 60회로 제한된다.
+# CI는 BuildKit secret(gh_token)으로 토큰을 넘겨 공유 러너 IP의 rate limit을 피한다.
+if [ -s /run/secrets/gh_token ]; then
+    GH_TOKEN="$(cat /run/secrets/gh_token)"
+    export GH_TOKEN
+fi
+
+# gh-stack: GitHub 네이티브 stacked PR / gh-actions-lock: Actions 의존성 lock·검증
+gh extension install github/gh-stack || { echo "❌ Failed to install github/gh-stack" >&2; exit 1; }
+gh extension install github/gh-actions-lock || { echo "❌ Failed to install github/gh-actions-lock" >&2; exit 1; }
+
+# 설치 확인 (`gh extension list`는 인증이 필요하므로 각 확장을 직접 실행한다)
+if gh stack --version &> /dev/null && gh actions-lock --help &> /dev/null; then
+    echo "✅ GitHub CLI extensions installation completed!"
+    gh stack --version
+else
+    echo "❌ GitHub CLI extensions verification failed!" >&2
+    exit 1
+fi