PR Reviewer MCP Server

An MCP (Model Context Protocol) server that connects Claude to GitHub, allowing it to list repositories, browse open pull requests, and inspect PR diffs — all from within Claude Code.

Prerequisites

• Python 3.11+
• uv — fast Python package manager
• Claude Code CLI installed (npm i -g @anthropic-ai/claude-code)
• A GitHub Personal Access Token with repo scope

Setup

1. Clone the repository

git clone https://github.com/subhamyadav580/pr-reviewer.git
cd pr-reviewer

2. Install dependencies

uv sync

This creates a .venv and installs all pinned dependencies from uv.lock.

3. Get a GitHub Personal Access Token

Go to GitHub → Settings → Developer settings → Personal access tokens and create a token with at minimum the repo scope (add read:org if your org repos are private).

4. Register the MCP server with Claude Code

Run this once — it registers the server at user scope so it's available in every project:

claude mcp add pr-reviewer -s user \
  -e GITHUB_TOKEN=ghp_xxxxxxxxxxxxxxxxxxxx \
  -e GITHUB_ORG=your-github-org-name \
  -- /absolute/path/to/pr-reviewer/.venv/bin/python \
     /absolute/path/to/pr-reviewer/main.py

Replace:

• ghp_xxxxxxxxxxxxxxxxxxxx — your GitHub PAT
• your-github-org-name — the GitHub org you want to query (e.g. my-company)
• /absolute/path/to/pr-reviewer — the full path where you cloned this repo

Verify it was registered:

claude mcp list

You should see pr-reviewer in the output.

5. (Optional) Install the /review-pr slash command

The repo ships with a review-pr.md slash command that gives Claude a structured, step-by-step review workflow. Copy it into your global Claude commands folder:

mkdir -p ~/.claude/commands
cp /absolute/path/to/pr-reviewer/review-pr.md ~/.claude/commands/review-pr.md

Now in any Claude Code session type /review-pr and Claude will:

1. List all org repositories for you to pick from
2. Show open PRs in the selected repo
3. Fetch the PR details and diff
4. Post a structured review with Blockers / Suggestions / Positives and a merge recommendation

Available MCP Tools

Tool	Description
list_org_repositories	Lists all repositories in the configured GitHub org
list_open_pull_requests(repo_full_name)	Lists open PRs for a repo (e.g. "my-org/my-repo")
get_pull_request_details(repo_full_name, pr_number)	Returns PR metadata: title, body, author, file count, additions/deletions
get_pull_request_diff(repo_full_name, pr_number)	Returns per-file diffs with the raw unified diff patch

Usage

Once registered you can talk to Claude naturally:

"List all open PRs in my org" "Show me the diff for PR #42 in my-org/backend" "Review PR #15 in my-org/frontend — flag bugs and style issues"

Or use the /review-pr slash command for a guided, structured review flow.

Project Structure

pr-reviewer/
├── main.py          # MCP server — all tool definitions
├── review-pr.md     # Slash command for Claude Code (/review-pr)
├── pyproject.toml   # Project metadata and dependencies
├── uv.lock          # Pinned dependency versions
├── .python-version  # Python version pin (3.11)
└── .env.example     # Template — copy to .env for local use

Claude Desktop

If you prefer Claude Desktop instead of the CLI, add this to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS):

{
  "mcpServers": {
    "pr-reviewer": {
      "command": "/absolute/path/to/pr-reviewer/.venv/bin/python",
      "args": ["/absolute/path/to/pr-reviewer/main.py"],
      "env": {
        "GITHUB_TOKEN": "ghp_xxxxxxxxxxxxxxxxxxxx",
        "GITHUB_ORG": "your-github-org-name"
      }
    }
  }
}

Restart Claude Desktop after saving.

Development

Run the server manually to test it:

uv run python main.py

To add a new tool, define a function decorated with @mcp.tool() in main.py. FastMCP exposes it to Claude automatically.