MCP Bundle file format
View All TagsIf you've ever installed an app on your computer—double-clicking a .dmg file on Mac or a .exe on Windows—you already understand .mcpb files.
Anthropic introduced the .mcpb extension (MCP Bundle) as the standard packaging format for distributing MCP servers. Think of it as the "app bundle" for AI tools: one file that contains everything needed to give your AI assistant new capabilities.
I spent two hours staring at Claude Desktop wondering why my MCP server wouldn't connect. The config looked perfect. The server ran fine standalone. But Claude showed no tools. The problem? A single trailing comma in my JSON config that Claude silently ignored. This is everything I wish the docs had told me upfront.
There are two ways to add MCP servers to Claude Desktop: .mcpb files (one-click install) or manual JSON config (full control). This guide covers both, plus the debugging steps you'll inevitably need.
Config file location (if that's all you need):
~/Library/Application Support/Claude/claude_desktop_config.json%APPDATA%\Claude\claude_desktop_config.json~/.config/Claude/claude_desktop_config.jsonOr open it directly: Claude Desktop → Settings → Developer → Edit Config.
New to MCP? Start with Introduction to MCP to understand what it is and how it works.
