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What is a .mcpb File? App Bundles for AI

· 5 min read
Tony Lewis
MCPBundles

If 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.

The Problem .mcpb Solves​

Before .mcpb, installing MCP servers was messy:

  • Different programming languages (Python, Node.js, Go)
  • Dependency management nightmares
  • Manual configuration files
  • Platform compatibility issues

With .mcpb, you get:

  • One file containing everything
  • One click to install
  • Zero configuration (for most cases)

It's portability and ease of installation wrapped into a single standard.

How It Works​

The .mcpb format is beautifully simple:

  1. Developer packages their MCP server into a single .mcpb file
  2. User downloads the file from a marketplace, GitHub, or service like MCPBundles
  3. Double-click to install in Claude Desktop
  4. Tools are immediately available to the AI

No terminal commands. No dependency installation. No config file editing. Just download and go.

MCPBundles' Cloud-Connected Approach​

Here's where MCPBundles does something different: our .mcpb files don't run a local server on your machine. Instead, they're lightweight bridges that connect to our cloud infrastructure.

Why This Matters​

Traditional .mcpb files:

  • Run entirely on your computer
  • You manage credentials locally
  • Updates require downloading new files
  • Single-service tools

MCPBundles .mcpb files:

  • Connect to cloud-hosted bundles
  • Credentials managed centrally (encrypted)
  • Automatic updates (no reinstallation)
  • Multi-provider tool aggregation

Think of it like streaming services: Netflix doesn't download every movie to your device—you stream from their servers. MCPBundles works the same way, but for AI tools.

Real-World Example​

Let's say you want to give Claude access to your sales workflow tools. Here's how it works with MCPBundles:

Step 1: Get Your API Key​

Visit your MCPBundles Settings and copy your API key. This connects Claude to your account.

Step 2: Download the Bundle​

Browse to the Sales Pipeline bundle (or any bundle) and click "Download .mcpb". You'll get a file like sales-pipeline-bundle.mcpb.

Step 3: Install in Claude Desktop​

Double-click the file. Claude Desktop detects it and prompts you to enter your API key. Done.

Step 4: Start Using Tools​

Open Claude and ask: "What sales tools do you have access to?" Claude will list all the tools from your bundle—Smartlead, Salesforce, Gmail, Calendly, and more—ready to use.

Behind the scenes, the .mcpb file connected Claude to the MCPBundles cloud, where your bundle is hosted with all your configured credentials and providers.

Two Ways to Connect​

MCPBundles supports both connection methods:

MCP URL (Universal)​

https://mcp.mcpbundles.com/bundle/sales-pipeline

Works with any MCP-compatible client:

  • ChatGPT
  • Cursor
  • Windsurf
  • Claude Code
  • VS Code Copilot

Just paste the URL into your AI's connector settings.

.mcpb File (Claude Desktop Optimized)​

sales-pipeline-bundle.mcpb

Optimized for Claude Desktop:

  • One-click installation
  • Built-in credential prompts
  • Automatic server configuration

Both methods connect to the same cloud-hosted bundle. The .mcpb file is just a more convenient installer for Claude Desktop users.

The Future of AI Tool Distribution​

If MCP is the operating system for AI-native applications, then .mcpb is the application bundle format. Just as we rely on:

  • .jar files in Java
  • .deb packages in Linux
  • .vsix extensions in VS Code

.mcpb files are becoming the standard for AI tool distribution.

Why This Matters for the Ecosystem​

Easier for developers: Package once, distribute everywhere
Easier for users: Install with a click, no technical knowledge needed
Better for growth: Lower barriers = faster ecosystem expansion

MCPBundles Advantage​

Here's what makes MCPBundles .mcpb files special:

Cloud-Hosted Infrastructure​

No local server setup or maintenance. The bundle runs in our cloud, not on your machine.

Automatic Updates​

When we add tools or improve functionality, changes deploy automatically. No reinstallation needed.

Centralized Credentials​

Configure your API keys once in your dashboard. They're encrypted at rest and automatically injected when tools are called.

Multi-Provider Aggregation​

One bundle can combine tools from 5+ different APIs. Instead of installing separate servers for GitHub, Slack, Salesforce, HubSpot, and Gmail, you get one bundle with all five integrated.

Getting Started​

Ready to try .mcpb installation?

  1. Install Claude Desktop from claude.ai/download
  2. Sign up at MCPBundles at mcpbundles.com/register
  3. Get your API key from Dashboard Settings
  4. Download a bundle from our catalog
  5. Double-click and go

For detailed instructions, check our Getting Started Guide.

The Bottom Line​

.mcpb files solve the MCP server installation problem. They make distributing AI tools as easy as sharing an app.

MCPBundles takes it further: our .mcpb files connect you to cloud-hosted bundles with automatic updates, centralized credential management, and multi-provider tool aggregation. You get the convenience of .mcpb installation plus the power of cloud infrastructure.

The future of AI tool distribution is here. It comes in a .mcpb file.

Questions? Check out our documentation or read more about how bundles work.