GitHub PR Reviewer MCP Server

A lightweight Model Context Protocol (MCP) server that connects Codex with GitHub and Notion. It allows Codex to fetch pull request changes, review code, and save approved reviews to Notion.

Architecture Diagram

Features

• Fetch pull request details and changed files from GitHub
• Analyse code using Codex
• Identify bugs, security risks, performance issues, and maintainability concerns
• Provide severity levels and recommended fixes
• Save approved reviews to Notion
• Integrate with Codex through FastMCP

Tech Stack

• Python
• FastMCP
• Codex CLI
• GitHub API
• Notion API
• uv
• python-dotenv

Setup

Create a .env file in the project root:

GITHUB_TOKEN=your_github_token
NOTION_API_KEY=your_notion_api_key
NOTION_PAGE_ID=your_notion_page_id

Install the project dependencies:

uv sync

Add the MCP server to Codex:

codex mcp add github-pr-reviewer -- uv --directory "C:\path\to\pr_reviewer" run python "src\pr_reviewer\pr_analyzer.py"

Verify the MCP server:

codex mcp list

Usage

Start Codex:

codex

Then provide a GitHub pull request URL:

Use the github-pr-reviewer MCP server to review this pull request:

https://github.com/OWNER/REPOSITORY/pull/PR_NUMBER

Fetch the pull request changes and review the code for bugs, security issues,
performance problems, and maintainability concerns. Do not save the review
to Notion until I approve it.

After reviewing the result:

I approve this review. Save the complete review to Notion using the
github-pr-reviewer MCP server.

Security

Never commit API tokens or the .env file.

Add the following entries to .gitignore:

.env
.venv/
__pycache__/

Author

Badar Rasheed Butt

AI Engineer