diff --git a/.claude/commands/optimize.md b/.claude/commands/optimize.md
new file mode 100644
index 0000000..0dfe632
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+++ b/.claude/commands/optimize.md
@@ -0,0 +1,249 @@
+# Performance Optimization Analysis Command
+
+Analyze the blog codebase from a performance optimization perspective and provide improvement recommendations as a senior frontend developer.
+
+## Input
+
+$ARGUMENTS: Analysis target (optional)
+- Specific file path: `src/app/post/[id]/page.tsx`
+- Specific directory: `src/app/_components/`
+- Analysis type: `bundle`, `rendering`, `data-fetching`, `images`
+- If empty: Full codebase analysis
+
+## Reference Skill
+
+**Always analyze based on rules from `.claude/skills/react-best-practices/SKILL.md`.**
+
+Individual rule details: `.claude/skills/react-best-practices/rules/*.md`
+
+## Analysis Process
+
+### 1. Priority 1: Eliminating Waterfalls (CRITICAL)
+
+**Related rules:** `async-*`
+
+```bash
+# Promise.all usage
+grep -r "Promise.all" src/ --include="*.tsx" --include="*.ts"
+
+# Sequential await patterns (potential Waterfall) - async-parallel violation
+grep -rn "await" src/ --include="*.tsx" | head -30
+
+# Suspense boundary usage - async-suspense-boundaries
+grep -r "<Suspense" src/ --include="*.tsx"
+```
+
+**Checklist:**
+- [ ] `async-parallel`: Use Promise.all() for independent operations
+- [ ] `async-defer-await`: Move await to actual usage point
+- [ ] `async-suspense-boundaries`: Stream content with Suspense
+
+### 2. Priority 2: Bundle Size Optimization (CRITICAL)
+
+**Related rules:** `bundle-*`
+
+```bash
+# Barrel import anti-pattern - bundle-barrel-imports violation
+grep -r "export \* from" src/ --include="index.ts"
+grep -r "from \".*/index\"" src/ --include="*.tsx"
+
+# Dynamic import usage - bundle-dynamic-imports
+grep -r "dynamic(" src/ --include="*.tsx"
+grep -r "import(" src/ --include="*.tsx" --include="*.ts"
+
+# Client component ratio
+grep -r "use client" src/ --include="*.tsx" | wc -l
+```
+
+**Checklist:**
+- [ ] `bundle-barrel-imports`: Import directly, avoid barrel files
+- [ ] `bundle-dynamic-imports`: Use next/dynamic for heavy components
+- [ ] `bundle-defer-third-party`: Load analytics/logging after hydration
+- [ ] `bundle-preload`: Preload on hover/focus for perceived speed
+
+### 3. Priority 3: Server-Side Performance (HIGH)
+
+**Related rules:** `server-*`
+
+```bash
+# React.cache() application - server-cache-react
+grep -r "import { cache }" src/app/api/
+grep -rn "export const" src/app/api/dato/ --include="*.ts"
+
+# Minimize data passed to client - server-serialization
+grep -r "PostType\|PostWithoutMarkdownType" src/ --include="*.tsx"
+
+# Parallel fetching - server-parallel-fetching
+grep -r "Promise.all" src/app/ --include="*.tsx"
+```
+
+**Checklist:**
+- [ ] `server-cache-react`: Apply React.cache() to all API functions
+- [ ] `server-serialization`: Minimize data passed to client components
+- [ ] `server-parallel-fetching`: Restructure components for parallel fetching
+
+### 4. Priority 4: Client-Side Data Fetching (MEDIUM-HIGH)
+
+**Related rules:** `client-*`
+
+```bash
+# SWR usage - client-swr-dedup
+grep -r "useSWR\|from \"swr\"" src/
+
+# Global event listener duplication - client-event-listeners
+grep -r "addEventListener" src/ --include="*.tsx"
+grep -r "removeEventListener" src/ --include="*.tsx"
+```
+
+**Checklist:**
+- [ ] `client-swr-dedup`: Use SWR for automatic request deduplication
+- [ ] `client-event-listeners`: Deduplicate global event listeners
+
+### 5. Priority 5: Re-render Optimization (MEDIUM)
+
+**Related rules:** `rerender-*`
+
+```bash
+# Inline function/object patterns (cause re-renders)
+grep -r "onClick={() =>" src/ --include="*.tsx" | head -20
+grep -r "style={{" src/ --include="*.tsx" | head -20
+
+# useCallback/useMemo usage
+grep -r "useCallback\|useMemo" src/ --include="*.tsx"
+
+# useEffect dependencies - rerender-dependencies
+grep -r "useEffect" src/ --include="*.tsx" -A 3 | head -40
+```
+
+**Checklist:**
+- [ ] `rerender-memo`: Extract expensive work into memoized components
+- [ ] `rerender-dependencies`: Use primitive dependencies in effects
+- [ ] `rerender-functional-setstate`: Use functional setState for stable callbacks
+- [ ] `rerender-lazy-state-init`: Pass function to useState for expensive initialization
+
+### 6. Priority 6: Rendering Performance (MEDIUM)
+
+**Related rules:** `rendering-*`
+
+```bash
+# Conditional rendering pattern - rendering-conditional-render
+grep -r "&& <" src/ --include="*.tsx" | head -20
+
+# content-visibility usage - rendering-content-visibility
+grep -r "content-visibility" src/ --include="*.scss"
+
+# Static JSX hoisting - rendering-hoist-jsx
+grep -r "const.*=.*<" src/ --include="*.tsx" | head -20
+```
+
+**Checklist:**
+- [ ] `rendering-conditional-render`: Use ternary instead of &&
+- [ ] `rendering-content-visibility`: Use content-visibility for long lists
+- [ ] `rendering-hoist-jsx`: Extract static JSX outside components
+
+### 7. Priority 7: JavaScript Performance (LOW-MEDIUM)
+
+**Related rules:** `js-*`
+
+```bash
+# RegExp in loops - js-hoist-regexp
+grep -rn "new RegExp" src/ --include="*.ts" --include="*.tsx"
+
+# Array method chaining - js-combine-iterations
+grep -r "\.filter.*\.map\|\.map.*\.filter" src/ --include="*.tsx"
+```
+
+**Checklist:**
+- [ ] `js-hoist-regexp`: Hoist RegExp creation outside loops
+- [ ] `js-combine-iterations`: Combine multiple filter/map into one loop
+- [ ] `js-set-map-lookups`: Use Set/Map for O(1) lookups
+
+### 8. Image Optimization
+
+```bash
+# Next.js Image component usage
+grep -r "from \"next/image\"" src/
+grep -r "<Image" src/ -A 3 | head -30
+
+# Plain img tag usage (warning)
+grep -r "<img" src/ --include="*.tsx"
+```
+
+**Checklist:**
+- [ ] Next/Image component usage
+- [ ] priority attribute (LCP images)
+- [ ] Appropriate sizes specification
+
+## Analysis Result Template
+
+```markdown
+## Performance Analysis Report
+
+### Executive Summary
+- Overall Performance Score: [A/B/C/D/F]
+- Key Bottlenecks:
+- Expected Improvement:
+
+---
+
+### Priority 1: Eliminating Waterfalls (CRITICAL)
+
+| Rule | Status | Location | Improvement |
+|------|--------|----------|-------------|
+| async-parallel | | | |
+| async-defer-await | | | |
+| async-suspense-boundaries | | | |
+
+---
+
+### Priority 2: Bundle Size Optimization (CRITICAL)
+
+| Rule | Status | Location | Improvement |
+|------|--------|----------|-------------|
+| bundle-barrel-imports | | | |
+| bundle-dynamic-imports | | | |
+| bundle-defer-third-party | | | |
+
+---
+
+### Priority 3: Server-Side Performance (HIGH)
+
+| Rule | Status | Location | Improvement |
+|------|--------|----------|-------------|
+| server-cache-react | | | |
+| server-serialization | | | |
+| server-parallel-fetching | | | |
+
+---
+
+### Priority 4-5: Client & Re-render (MEDIUM)
+
+| Rule | Status | Location | Improvement |
+|------|--------|----------|-------------|
+| client-swr-dedup | | | |
+| rerender-memo | | | |
+| rerender-dependencies | | | |
+
+---
+
+### Improvement Roadmap by Priority
+
+#### P0 - Critical (Immediate)
+- [ ]
+
+#### P1 - High (Within 1 week)
+- [ ]
+
+#### P2 - Medium (Within 2 weeks)
+- [ ]
+
+---
+
+*Analyzed by Claude Code with react-best-practices skill*
+```
+
+## Reference Documents
+
+- **React Best Practices**: `.claude/skills/react-best-practices/SKILL.md`
+- **Individual Rule Details**: `.claude/skills/react-best-practices/rules/*.md`
+- **Project Guidelines**: `CLAUDE.md`
\ No newline at end of file
diff --git a/todolist.md b/todolist.md
index 3293715..3828922 100644
--- a/todolist.md
+++ b/todolist.md
@@ -1,6 +1,78 @@
 # React Best Practices 개선 Todo List
 
-`posts/page.tsx` 컴포넌트 트리 분석 결과
+## 전체 코드베이스 성능 분석 (2026-01-18)
+
+**Overall Score: B+**
+
+### P0 - Critical (즉시 적용)
+
+- [ ] **React.cache() 전체 API 함수 적용** (`server-cache-react`)
+  - `src/app/api/dato/getPosts.ts` - cache 미적용
+  - `src/app/api/dato/getCategories.ts` - cache 미적용
+  - `src/app/api/dato/getPostIds.ts` - cache 미적용
+  - ✅ `src/app/api/dato/getPostById.ts` - 이미 적용됨
+  - 효과: 동일 렌더링 사이클 내 중복 API 요청 자동 제거
+
+```typescript
+// 적용 예시
+import { cache } from "react";
+
+const _getPosts = async <T>(query = GET_META_FIELDS): Promise<T> => {
+  // 기존 로직
+};
+
+export const getPosts = cache(_getPosts);
+```
+
+### P1 - High (1주 내 적용)
+
+- [ ] **Shiki dynamic import 적용** (`bundle-dynamic-imports`)
+  - 파일: `src/app/post/[id]/Markdown/_components/Code.tsx`
+  - 문제: shiki는 번들 사이즈가 큰 라이브러리
+  - 개선: dynamic import로 코드 스플리팅
+
+```typescript
+const highlightCode = async (code: string, language: string) => {
+  const { codeToHtml } = await import("shiki");
+  return codeToHtml(code, { lang: language, theme: "github-dark" });
+};
+```
+
+- [ ] **Barrel imports 제거** (`bundle-barrel-imports`)
+  - 파일: `src/types/index.ts`
+  - 문제: `export * from` 패턴이 tree-shaking 방해
+  - 개선: 직접 import 사용
+    - Before: `import { PostType } from "@/types"`
+    - After: `import { PostType } from "@/types/apiResponseType"`
+
+### P2 - Medium (2주 내 적용)
+
+- [ ] **Fuse.js lazy loading** (`bundle-conditional`)
+  - 파일: `src/app/_components/Search/index.tsx`
+  - 문제: 검색 기능이 항상 필요하지 않음
+  - 개선: Search 컴포넌트 진입 시점에 dynamic import 고려
+
+- [ ] **content-visibility 적용** (`rendering-content-visibility`)
+  - 파일: Posts 컴포넌트 스타일
+  - 적용 시점: 포스트 목록이 많아질 경우
+
+---
+
+## 잘 적용된 부분 (전체 분석)
+
+| 패턴 | 위치 | 상태 |
+|------|------|------|
+| Promise.all 병렬 페칭 | `SidebarWrapper/index.tsx:11` | ✅ |
+| Suspense boundaries | `layout.tsx:122`, `Markdown/index.tsx:40` | ✅ |
+| Third-party 지연 로딩 | `layout.tsx:69,81` (afterInteractive) | ✅ |
+| 데이터 직렬화 최적화 | `PostWithoutMarkdownType`, `Pick<>` 사용 | ✅ |
+| Next/Image 사용 | `Cards`, `MarkdownImage`, `Heading` | ✅ |
+| useMemo 적용 | `Search/index.tsx:17` (Fuse 인스턴스) | ✅ |
+| useDebounce 적용 | 검색 입력 최적화 | ✅ |
+
+---
+
+## `posts/page.tsx` 컴포넌트 트리 분석 결과
 
 ## 컴포넌트 트리 구조
 
@@ -84,4 +156,4 @@ posts/page.tsx (Server Component)
 
 ---
 
-*Generated: 2026-01-17*
+*Last Updated: 2026-01-18*