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diff --git a/.agent/.shared/ui-ux-pro-max/scripts/__pycache__/design_system.cpython-313.pyc b/.agent/.shared/ui-ux-pro-max/scripts/__pycache__/design_system.cpython-313.pyc
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diff --git a/.github/workflows/ai-review.yml b/.github/workflows/ai-review.yml
new file mode 100644
index 00000000..fd7ce3ef
--- /dev/null
+++ b/.github/workflows/ai-review.yml
@@ -0,0 +1,32 @@
+name: AI Code Reviewer
+
+on:
+  pull_request:
+    types: [opened, synchronize]
+
+permissions:
+  contents: read
+  pull-requests: write
+
+jobs:
+  review:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Code
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.10'
+
+      - name: Install Dependencies
+        run: |
+          pip install -r scripts/requirements.txt
+
+      - name: Run AI Reviewer
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          OPENROUTER_API_KEY: ${{ secrets.OPENROUTER_API_KEY }}
+        run: |
+          python scripts/ai_reviewer.py
diff --git a/.gitignore b/.gitignore
index 4f160266..d235da80 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@
 node_modules/
 .temp_ag_kit/
 antigravity-doc
+__pycache__
diff --git a/docs/PLAN-ai-code-reviewer.md b/docs/PLAN-ai-code-reviewer.md
new file mode 100644
index 00000000..b5898ad1
--- /dev/null
+++ b/docs/PLAN-ai-code-reviewer.md
@@ -0,0 +1,38 @@
+# Plan: Custom AI Code Reviewer (GitHub Actions + OpenRouter)
+
+## Goal Description
+Implement AI Code Reviewer using **OpenRouter** (Mistral) instead of Gemini. Fix dependency conflicts and ensure compliance with OpenRouter API standards.
+
+## User Review Required
+> [!IMPORTANT]
+> **API Key**: Ensure `OPENROUTER_API_KEY` is set in GitHub Secrets.
+> **Model**: Using `mistralai/devstral-2512:free` as requested (Note: verification of exact model ID recommended).
+
+## Proposed Changes
+
+### Dependencies
+#### [MODIFY] [requirements.txt](file:///Users/nghialuutrung/Desktop/antigravity-kit/scripts/requirements.txt)
+*   Update `openai>=1.55.0` to resolve `httpx` proxy argument conflict.
+*   Keep `PyGithub`.
+
+### Logic Script
+#### [MODIFY] [ai_reviewer.py](file:///Users/nghialuutrung/Desktop/antigravity-kit/scripts/ai_reviewer.py)
+*   **Client Initialization**:
+    ```python
+    client = OpenAI(
+        base_url="https://openrouter.ai/api/v1",
+        api_key=api_key,
+        default_headers={
+            "HTTP-Referer": "https://github.com/hapo-nghialuu/antigravity-kit", # Attribution
+            "X-Title": "Antigravity AI Reviewer"
+        }
+    )
+    ```
+*   **Model**: Set `MODEL_NAME = "mistralai/devstral-2512:free"`.
+*   **JSON Handling**: Add robust try-catch for JSON parsing as free models might chatter.
+
+## Verification Plan
+
+### Manual Verification
+1.  **Re-run GitHub Action**: Trigger the workflow again on the existing PR.
+2.  **Check Logs**: Verify "OpenRouter response received" and no 404/401 errors.
diff --git a/scripts/ai_reviewer.py b/scripts/ai_reviewer.py
new file mode 100644
index 00000000..e2de9925
--- /dev/null
+++ b/scripts/ai_reviewer.py
@@ -0,0 +1,179 @@
+import os
+import json
+import logging
+from github import Github
+from openai import OpenAI
+
+# Configure Logging
+logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')
+
+# Constants
+IGNORED_EXTENSIONS = ['.json', '.md', '.txt', '.yml', '.yaml', '.lock', '.png', '.jpg', '.jpeg', '.gif', '.svg']
+IGNORED_DIRS = ['dist', 'build', 'node_modules', '.github']
+MODEL_NAME = "mistralai/devstral-2512:free"
+
+def should_review(filename):
+    """Check if file should be reviewed based on extension and path."""
+    if any(filename.endswith(ext) for ext in IGNORED_EXTENSIONS):
+        return False
+    if any(part in filename.split('/') for part in IGNORED_DIRS):
+        return False
+    return True
+
+def get_pr_diff(repo, pr_number):
+    """Fetch PR diff using PyGithub."""
+    pr = repo.get_pull(pr_number)
+    files_data = []
+
+    for file in pr.get_files():
+        if not should_review(file.filename):
+            continue
+
+        # Only review added or modified files (not deleted)
+        if file.status == 'removed':
+            continue
+
+        files_data.append({
+            "filename": file.filename,
+            "patch": file.patch
+        })
+    return pr, files_data
+
+def analyze_code_with_openrouter(files_data):
+    """Send code diff to OpenRouter for review."""
+    api_key = os.getenv("OPENROUTER_API_KEY")
+    if not api_key:
+        logging.error("OPENROUTER_API_KEY not found in environment variables.")
+        return []
+
+    client = OpenAI(
+        base_url="https://openrouter.ai/api/v1",
+        api_key=api_key,
+        default_headers={
+            "HTTP-Referer": "https://github.com/hapo-nghialuu/antigravity-kit",
+            "X-Title": "Antigravity AI Reviewer"
+        }
+    )
+
+    # Construct Prompt
+    # We ask for a strict JSON response.
+    prompt = """
+    Bạn là một Senior Code Reviewer. Nhiệm vụ của bạn là review các đoạn code thay đổi trong Pull Request này.
+
+    Hãy chỉ ra các vấn đề nghiêm trọng:
+    1. Lỗi Logic (Logic Errors) - Rất quan trọng.
+    2. Vấn đề Bảo mật (Security Vulnerabilities) - Rất quan trọng.
+    3. Hiệu năng (Performance Issues).
+    4. Code xấu, khó bảo trì (Bad Practices).
+
+    Bỏ qua:
+    - Các lỗi format/style (đã có linter).
+    - Các thay đổi không quan trọng.
+
+    Dữ liệu input là JSON list các file kèm patch.
+    Hãy trả về kết quả là một JSON list thuần túy (không markdown block, không giải thích thêm), mỗi item có format sau:
+    [
+        {
+            "filename": "tên_file",
+            "line_number": số_dòng_trong_patch_để_comment,
+            "comment": "Nội dung review bằng tiếng Việt, ngắn gọn, súc tích."
+        }
+    ]
+
+    Nếu code tốt hoàn toàn, hãy trả về danh sách rỗng [].
+
+    CODE DIFF TO REVIEW:
+    """ + json.dumps(files_data)
+
+    try:
+        response = client.chat.completions.create(
+            model=MODEL_NAME,
+            messages=[
+                {"role": "system", "content": "You are a helpful code reviewer. Always respond with valid JSON code only. No markdown formatting."},
+                {"role": "user", "content": prompt}
+            ],
+            # Note: response_format={"type": "json_object"} sometimes requires 'json' in prompt or specific model support.
+            # We trust the prompt instruction for now.
+        )
+
+        content = response.choices[0].message.content.strip()
+
+        # Strip markdown code blocks if present (common issue with LLMs)
+        if content.startswith("```json"):
+            content = content[7:]
+        if content.startswith("```"):
+            content = content[3:]
+        if content.endswith("```"):
+            content = content[:-3]
+
+        content = content.strip()
+
+        logging.info("OpenRouter response received.")
+        return json.loads(content)
+    except json.JSONDecodeError:
+        logging.error(f"Failed to parse JSON response: {content}")
+        return []
+    except Exception as e:
+        logging.error(f"Error calling OpenRouter: {e}")
+        return []
+
+def post_comments(pr, comments):
+    """Post comments to the PR."""
+    commit = pr.get_commits().reversed[0] # Get latest commit
+
+    if not comments:
+        logging.info("No issues found. LGTM!")
+        return
+
+    logging.info(f"Posting {len(comments)} comments...")
+
+    for note in comments:
+        filename = note.get('filename')
+        line = note.get('line_number') # AI guess of the line
+        body = f"🤖 **AI Review**: {note.get('comment')}"
+
+        try:
+            if not line:
+                pr.create_issue_comment(f"File `{filename}`: {body}")
+                continue
+
+            pr.create_review_comment(body, commit, filename, line=int(line), side="RIGHT")
+        except Exception as e:
+            logging.warning(f"Failed to post comment on {filename}:{line}. Error: {e}")
+            pr.create_issue_comment(f"Could not comment on line {line} of {filename}. \n\n{body}")
+
+def main():
+    github_token = os.getenv("GITHUB_TOKEN")
+    event_path = os.getenv("GITHUB_EVENT_PATH")
+
+    if not github_token or not event_path:
+        logging.error("Missing GITHUB_TOKEN or GITHUB_EVENT_PATH.")
+        return
+
+    with open(event_path, 'r') as f:
+        event_data = json.load(f)
+
+    if 'pull_request' not in event_data:
+        logging.info("Not a pull_request event. Exiting.")
+        return
+
+    pr_number = event_data['pull_request']['number']
+    repo_name = event_data['repository']['full_name']
+
+    logging.info(f"Starting review for PR #{pr_number} in {repo_name}")
+
+    g = Github(github_token)
+    repo = g.get_repo(repo_name)
+    pr, files_data = get_pr_diff(repo, pr_number)
+
+    if not files_data:
+        logging.info("No reviewable files found.")
+        return
+
+    logging.info(f"Analyzing {len(files_data)} files...")
+    comments = analyze_code_with_openrouter(files_data)
+    post_comments(pr, comments)
+    logging.info("Review complete.")
+
+if __name__ == "__main__":
+    main()
diff --git a/scripts/requirements.txt b/scripts/requirements.txt
new file mode 100644
index 00000000..af700426
--- /dev/null
+++ b/scripts/requirements.txt
@@ -0,0 +1,2 @@
+PyGithub>=2.1.1
+openai>=1.55.0