MCP Bundler

1.2.5 verified Sat Apr 25 auth: no javascript

MCPB (MCP Bundle) bundler for Smithery MCP servers, version 1.2.5. Converts Smithery YAML configs into MCPB-compliant bundles with manifest, dot-notation flattening, and automatic type mapping. Supports Node.js >=18, programmatic API, and auto-detection of entry points. Differentiated from generic bundlers by its tight integration with the Smithery ecosystem and MCPB spec compliance.

Common errors

error Error: Cannot find module '@mcps/bundler' ↓

cause Package not installed or missing in node_modules.

fix

Run npm install @mcps/bundler

error SyntaxError: Unexpected token '{' ↓

cause Using CommonJS require() on an ESM-only package.

fix

Use import { bundleMCPServer } from '@mcps/bundler'; instead

error Error: Node.js version 16.x is not supported ↓

cause Minimum Node.js requirement is 18.x.

fix

Upgrade Node.js to version 18 or higher

error TypeError: (0 , bundler_1.bundleMCPServer) is not a function ↓

cause Attempting to call the default export when it does not exist.

fix

Use named import: import { bundleMCPServer } from '@mcps/bundler';

Warnings

breaking Requires Node.js >=18.0.0 due to ESM and modern features. ↓

fix Upgrade Node.js to version 18 or higher.

deprecated The `smitheryYaml` export was deprecated in v1.2.0; use `parseSmitheryYaml` instead. ↓

fix Replace import `{ smitheryYaml }` with `{ parseSmitheryYaml }`.

gotcha Minification is enabled by default, which may increase bundle time and cause issues with dynamic imports. ↓

fix Set `minify: false` in options if you encounter issues with dynamic imports or desire faster builds.

gotcha Entry point auto-detection may pick the wrong file if multiple `main.ts` or `index.ts` exist; always specify `entry` explicitly for projects with multiple source roots. ↓

fix Pass the `entry` option explicitly when calling `bundleMCPServer`.

Install

npm install mcp-bundler

yarn add mcp-bundler

pnpm add mcp-bundler

Imports

bundleMCPServer

wrong

const bundleMCPServer = require('@mcps/bundler');

correct

import { bundleMCPServer } from '@mcps/bundler';

Package is ESM-only; CommonJS require() will fail.

parseSmitheryYaml
```
import { parseSmitheryYaml } from '@mcps/bundler';
```
Use to parse Smithery YAML content directly.
smitheryConfigToUserConfig
```
import { smitheryConfigToUserConfig } from '@mcps/bundler';
```
Converts Smithery config schema to MCPB user config format.

smitheryToManifest

wrong

import smitheryToManifest from '@mcps/bundler';

correct

import { smitheryToManifest } from '@mcps/bundler';

Named export only; default export is not available.

Quickstart

Shows how to use the programmatic API to bundle a Smithery MCP server project.

import { bundleMCPServer } from '@mcps/bundler';
import { resolve } from 'path';

const projectPath = resolve('./my-server');
const outputDir = resolve('./dist');

const result = await bundleMCPServer(projectPath, outputDir, {
  minify: true,
  entry: 'src/index.ts'
});

console.log(`Bundle size: ${result.bundleSize} KB`);