build-mcpb

npx skills add anthropics/claude-plugins-official --skill build-mcpb --agent claude-code

Same command for any agent — swap --agent for codex, cursor, copilot.

# Build an MCPB (Bundled Local MCP Server) MCPB is a local MCP server **packaged with its runtime**. The user installs one file; it runs without needing Node, Python, or any toolchain on their machine. It's the sanctioned way to distribute local MCP servers. > MCPB is the **secondary** distribution path. Anthropic recommends remote MCP servers for directory listing — see https://claude.com/docs/connectors/building/what-to-build. **Use MCPB when the server must run on the user's machine** — reading local files, driving a desktop app, talking to localhost services, OS-level APIs. If your server only hits cloud APIs, you almost certainly want a remote HTTP server instead (see `build-mcp-server`). Don't pay the MCPB packaging tax for something that could be a URL. --- ## What an MCPB bundle contains ``` my-server.mcpb (zip archive) ├── manifest.json ← identity, entry point, config schema, compatibility ├── server/ ← your MCP server code │ ├── index.js │ └── node_modules/ ← bundled dependencies (or vendored) └── icon.png ``` The host reads `manifest.json`, launches `server.mcp_config.command` as a **stdio** MCP server, and pipes messages. From your code's perspective it's identical to a

npm install
npx esbuild src/index.ts --bundle --platform=node --outfile=server/index.js
npx @anthropic-ai/mcpb pack
pip install -t server/vendor -r requirements.txt
Interactive manifest creation (first time)
npx @anthropic-ai/mcpb init
Run the server directly over stdio, poke it with the inspector
npx @modelcontextprotocol/inspector node server/index.js
Validate manifest against schema, then pack
npx @anthropic-ai/mcpb validate