Getting Started with MCP Desktop Extensions (DXT) in Claude Desktop

MCP Desktop Extensions (DXT) allow developers to package and install Model Context Protocol (MCP) servers into Claude Desktop with a single click—eliminating the need for terminal commands or complex setup. This beginner-friendly guide walks through the fundamentals of DXT and demonstrates how to install and use .dxt extensions to connect Claude with external tools, starting with a basic file system integration and concluding with a real-world Twitter analytics use case.

What Are Desktop Extensions (.dxt)?

.dxt files are zip-based packages that bundle a local MCP server and a manifest.json file describing its capabilities. This packaging format enables one-click installation of MCP servers into Claude Desktop on Windows and macOS¹.

Why Use DXT? Key Benefits

• No manual dependencies: Claude Desktop includes built-in runtime support, eliminating the need to install tools like Node.js.
• Secure configuration: Secrets are collected via a GUI and stored in the OS keychain².
• Cross-platform and auto-updating: Supports Windows and macOS, with install audits and seamless updates.

How DXT Works Internally

1. Manifest Parsing: Claude reads the manifest.json file to understand the server's permissions, parameters, and commands.
2. Environment Setup: Users provide configuration (e.g., API keys, folder paths) via a secure GUI.
3. Server Launch: Claude launches the MCP server locally and forwards prompts.
4. Tool Invocation: Commands (e.g., list_files) are passed to the server via JSON-RPC over stdio.

Getting Started³

1. Install the DXT CLI Globally

2. Initialize a New Project

• Create a new folder and open it in your preferred code editor (e.g., VS Code, Cursor).
• In the terminal, run:

• Fill in the configuration details or replicate the example shown below. This generates your manifest.json file.

3. Edit the manifest.json File⁴

Update the server configuration as follows:

This configuration enables multi-directory access via the filesystem MCP server.

4. Package the Extension

This command builds your .dxt file.

5. Install in Claude Desktop

• Double-click the generated .dxt file, or manually install it via: Settings > Extensions > Advanced Settings > Install Extensions
• Select your .dxt file.

After installation, select the folders you wish to expose and restart Claude Desktop.

6. Verify the Extension

In Claude Desktop Chat, type:

You will be prompted to authorize access.

Once authorized, Claude will display the list of accessible folders.

Conclusion

This feels like one of those "before and after" moments in developer tooling. DXT transforms MCP from something for the technically adventurous into something anyone can use. I'm already dreaming up extensions for my specific workflows—a project manager that connects to GitHub, a research assistant that taps into scientific databases, or a writing helper that integrates with my note-taking system.

The best part? Each one will be a simple double-click away. If you've been curious about extending Claude but intimidated by the setup, now's the time to dive in. The water's finally warm.

References