DXT File

Desktop Extension file format (.dxt) that packages MCP servers with dependencies and metadata into a single installable archive using ZIP compression.

DXT File

A DXT file is a ZIP archive with the .dxt extension that contains a complete MCP server package. It includes the server code, all dependencies, configuration metadata, and optional assets like icons—everything needed for one-click installation.

File Structure

example.dxt (ZIP archive)
├── manifest.json         # Required: Extension metadata
├── server/              # Server implementation
│   ├── index.js         # Main entry point
│   └── utils.js         # Supporting modules
├── node_modules/        # Bundled dependencies
├── package.json         # Optional: Package definition
├── icon.png            # Optional: Extension icon
└── assets/             # Optional: Additional resources
    └── screenshots/    # Optional: Preview images

Manifest Structure

The manifest.json is the only required file:

{
  "dxt_version": "0.1",
  "name": "my-extension",
  "version": "1.0.0",
  "description": "A simple MCP extension",
  "author": {
    "name": "Extension Author"
  },
  "server": {
    "type": "node",
    "entry_point": "server/index.js",
    "mcp_config": {
      "command": "node",
      "args": ["${__dirname}/server/index.js"]
    }
  }
}

Server Types

Type	Entry Point	Use Case
`node`	JavaScript/TypeScript file	Most common, uses bundled Node.js
`python`	Python script	Data processing, ML integrations
`binary`	Executable file	System utilities, compiled tools

Template Variables

DXT files support runtime substitution:

Variable	Description	Example
`${__dirname}`	Extension installation directory	`/path/to/extension`
`${user_config.key}`	User-provided configuration	API keys, paths
`${HOME}`	User home directory	`/Users/username`
`${TEMP}`	System temporary directory	`/tmp`

Platform Support

Extensions can include platform-specific configurations:

{
  "server": {
    "mcp_config": {
      "platforms": {
        "win32": {
          "command": "node.exe",
          "env": {"TEMP_DIR": "${TEMP}"}
        },
        "darwin": {
          "env": {"TEMP_DIR": "${TMPDIR}"}
        }
      }
    }
  }
}

Installation Process

Download - User obtains .dxt file
Import - Drag file into Claude Desktop Settings
Validation - Host validates manifest and dependencies
Configuration - User provides required settings
Deployment - Extension unpacked and registered
Activation - Server becomes available to LLM

Security Features

Manifest Validation - Ensures proper structure and permissions
Dependency Scanning - Checks for known vulnerabilities
Sandboxed Execution - Servers run in isolated environments
Permission System - Explicit user consent for sensitive operations

Development Tools

# Install DXT toolchain
npm install -g @anthropic-ai/dxt

# Initialize new extension
dxt init

# Validate manifest
dxt validate

# Package extension
dxt pack

File Format Benefits

Benefit	Description
Portability	Single file contains everything needed
Versioning	Built-in version management and updates
Compression	ZIP format reduces download size
Metadata	Rich information for discovery and installation
Validation	Checksum verification and integrity checks