GitHub PR Review MCP Server

An MCP server that gives any LLM client the ability to list, read, review, and comment on GitHub pull requests — turning your AI assistant into a fully capable code reviewer.

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Overview

This server wraps the GitHub REST API using FastMCP, exposing pull request operations as tools any MCP-compatible client can call. Connect it to Claude Desktop and you can ask Claude to review your open PRs, read diffs, post inline comments, approve, or request changes — all without leaving your conversation.

The server maintains a single authenticated httpx client across its lifetime, initialised on startup and shared across all tool calls via FastMCP's lifespan context.

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Tools

Tool	Description
list_open_prs	List all open PRs with author, title, draft status, and URL
get_pr_diff	Get file changes and unified diffs for a specific PR
get_pr_comments	Get all existing review comments on a PR
post_review_comment	Post an inline comment on a specific file and line
approve_pr	Approve a PR with an optional review message
request_changes	Request changes on a PR with a review message

Note: approve_pr and request_changes require the authenticated user to be different from the PR author. GitHub does not permit self-review.

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Project Structure

github-pr-mcp/
├── server.py          # FastMCP instance, lifespan, tool registration
├── config.py          # Environment variables and constants
├── tools/
│   ├── __init__.py
│   ├── prs.py         # list_open_prs, get_pr_diff
│   └── reviews.py     # get_pr_comments, post_review_comment, approve_pr, request_changes
├── .env               # Your secrets (never committed)
├── .env.example       # Template
├── requirements.txt
├── Dockerfile
└── README.md

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Requirements

• Python 3.11+
• uv
• A GitHub Personal Access Token with repo scope

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Setup

1. Clone the repository:

git clone https://github.com/Festuskipkoech/github-pr-mcp.git
cd github-pr-mcp

2. Install dependencies:

uv sync

3. Configure your environment:

cp .env.example .env

Edit .env and fill in your values:

GITHUB_TOKEN=your_personal_access_token
GITHUB_OWNER=your_github_username
GITHUB_REPO=your_repository_name

Generate a token at GitHub Settings → Developer Settings → Personal Access Tokens. Enable full repo scope for read and write access.

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Running Locally

uv run python server.py

Or with the FastMCP CLI on Streamable HTTP transport:

fastmcp run server.py:mcp --transport streamable-http

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Testing with MCP Inspector

Start the server in one terminal:

fastmcp run server.py:mcp --transport streamable-http

Launch the Inspector in a second terminal:

npx -y @modelcontextprotocol/inspector

In the Inspector UI:

• Transport: Streamable HTTP
• URL: http://127.0.0.1:8000/mcp
• Click Connect

Recommended test sequence:

Step	Tool	Input
1	list_open_prs	(no arguments)
2	get_pr_diff	{"pr_number": 1}
3	get_pr_comments	{"pr_number": 1}
4	post_review_comment	{"pr_number": 1, "body": "Looks good", "path": "file.py", "line": 1}

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Using with Claude Desktop

Add the following to ~/.config/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "github-pr-review": {
      "command": "/home/your-user/.local/bin/uv",
      "args": [
        "run",
        "--directory",
        "/absolute/path/to/github-pr-mcp",
        "python",
        "server.py"
      ]
    }
  }
}

Use the full path to uv (find it with which uv). Credentials are read from the .env file automatically — no need to pass them in the config.

Restart Claude Desktop, then try:

List all open pull requests in my repo and show me the diff for PR number 1

Claude calls list_open_prs and get_pr_diff and returns structured results:

Full PR diff and file changes returned inline:

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Running with Docker

docker build -t github-pr-mcp .
docker run --env-file .env -p 8000:8000 github-pr-mcp

For Streamable HTTP transport, update server.py to run with:

mcp.run(transport="streamable-http", host="0.0.0.0", port=8000)

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Troubleshooting

Error	Cause	Fix
401 Unauthorized	Invalid or expired token	Regenerate PAT on GitHub
403 Forbidden	Token lacks write scope	Enable full repo scope on your PAT
404 Not Found	Wrong owner or repo name	Check .env — use just the repo name, not the full URL
422 Unprocessable on approve	Self-review attempt	GitHub blocks approving your own PRs by design