GitHub Assistant MCP Server

A Model Context Protocol (MCP) server that connects Claude Desktop to the GitHub API. Ask Claude natural-language questions about any public GitHub repository — issues, pull requests, repo metadata, READMEs — without leaving your conversation.

What is MCP?

MCP (Model Context Protocol) is an open standard that lets AI applications connect to external tools and data sources through a uniform interface. Think of it as a USB-C port for AI — any MCP-compatible client (Claude Desktop, Cursor, VS Code Copilot, etc.) can plug into any MCP server.

Claude Desktop (MCP Host)
       |
       |  stdio — JSON-RPC 2.0
       v
GitHub Assistant MCP Server   <-- this project
       |
       |  HTTPS
       v
  GitHub REST API v3

When you ask Claude "what are the open issues in microsoft/vscode?", Claude calls this server's list_issues tool, the server fetches data from GitHub, and returns the answer — all transparently within the conversation.

Tools

Tool	Description
search_repos	Search GitHub repos by keyword. Supports qualifiers like language:python, stars:>1000
get_repo	Get metadata for a specific repo: stars, forks, language, license, topics
list_issues	List open/closed issues for a repo (excludes PRs)
get_issue	Get the full body and details of a specific issue by number
list_pull_requests	List open/closed PRs including draft status and branch info

Resources

URI Pattern	Description
repo://{owner}/{repo}/readme	The raw README markdown for any repository

Example Conversations

"Search for the most starred Python web frameworks on GitHub"

"Tell me about the microsoft/vscode repository"

"What are the 10 most recently updated open issues in microsoft/vscode?"

"Show me the details of issue #301645 in microsoft/vscode"

"What open pull requests are there in fastapi/fastapi?"

Setup

Prerequisites

• Python 3.13+
• uv package manager
• Claude Desktop
• A GitHub Personal Access Token (for 5,000 req/hr vs 60 without)

Install

git clone https://github.com/yourusername/github-mcp
cd github-mcp

# Install dependencies
uv sync

# Copy and fill in your token
cp .env.example .env
# Edit .env and set GITHUB_TOKEN=ghp_your_token_here

Connect to Claude Desktop

Add the following to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "github-assistant": {
      "command": "/path/to/uv",
      "args": [
        "--directory", "/absolute/path/to/github-mcp",
        "run", "python", "-m", "github_mcp.server"
      ],
      "env": {
        "GITHUB_TOKEN": "ghp_your_token_here"
      }
    }
  }
}

Restart Claude Desktop. You should see a hammer icon in the chat input — that's your MCP tools.

Project Structure

github-mcp/
├── src/
│   └── github_mcp/
│       ├── __init__.py
│       ├── github_client.py   # GitHub REST API wrapper (pure async httpx)
│       └── server.py          # MCP server — tool & resource definitions
├── .env                       # Your GITHUB_TOKEN (never commit this)
├── .gitignore
├── pyproject.toml
└── README.md

Architecture

github_client.py is a thin async wrapper around the GitHub REST API v3. It has no knowledge of MCP — just Python functions that return dicts. This separation makes it easy to test independently.

server.py is the MCP layer. It creates a FastMCP instance and decorates functions with @mcp.tool() and @mcp.resource(). FastMCP auto-generates the JSON Schema for each tool from Python type hints and docstrings — the same docstring you write for humans is what Claude reads to decide when to call your tool.

Transport: stdio (stdin/stdout). Claude Desktop launches this server as a subprocess and sends JSON-RPC 2.0 messages through stdin. The server writes responses to stdout. This is why we log to stderr — stdout is reserved for the protocol.

Key Concepts Learned

• MCP primitives: Tools (callable functions), Resources (readable data), Prompts (templates)
• JSON-RPC 2.0: The wire protocol — request/response with id, notification without
• Tool descriptions matter: The LLM reads your docstring to decide when to call a tool
• stdio transport: No HTTP server needed for local tools — just a process with pipes
• Async Python: httpx.AsyncClient for non-blocking GitHub API calls
• Auth patterns: Token injection via environment variables — never hardcoded

License

MIT