How do I use MCP Opener?

1. Click on "Install Server". 2. Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state. 3. In the chat, type `@` followed by the MCP server name and your instructions, e.g., "`@MCP Opener` open my Documents folder" That's it! The server will respond to your query, and you can continue using it as needed. Here is a [step-by-step guide with screenshots](https://glama.ai/blog/2025-07-08-how-to-install-and-use-mcp-servers).

MCP Opener

Model Context Protocol server for opening files, folders, and browsers across different operating systems. Designed specifically to handle Linux Flatpak Firefox complexities on distributions like Fedora Bluefin.

Features

Open Folders: Launch system file manager (Nautilus, Finder, Explorer, etc.)
Open Files: Open files with their default applications
Open Browser: Open URLs with configurable browser preferences
Flatpak Firefox Support: Auto-detects and handles Flatpak Firefox installations
Cross-Platform: Works on Linux, macOS, and Windows
Smart File Handling: Automatically copies files to /tmp for Flatpak browser access when needed

Installation

# Install dependencies pnpm install # Build pnpm build # Install globally (optional) pnpm link --global

Configuration

Configure via environment variables in your .env file or Claude Code MCP settings:

# Preferred browser: 'firefox' | 'chrome' | 'chromium' | 'default' MCP_OPENER_BROWSER=firefox # Explicitly set if Firefox is installed via Flatpak (auto-detected if omitted) MCP_OPENER_FIREFOX_FLATPAK=true # Whether to copy files to /tmp for Flatpak access (default: true) MCP_OPENER_TMP_COPY=true

Claude Code Configuration

Add to your Claude Code MCP settings (.claude/settings.json or global settings):

{ "mcpServers": { "opener": { "command": "node", "args": ["/path/to/mcp-opener/dist/index.js"], "env": { "MCP_OPENER_BROWSER": "firefox", "MCP_OPENER_FIREFOX_FLATPAK": "true", "MCP_OPENER_TMP_COPY": "true" } } } }

Or using pnpm:

{ "mcpServers": { "opener": { "command": "pnpm", "args": ["--dir", "/path/to/mcp-opener", "exec", "node", "dist/index.js"], "env": { "MCP_OPENER_BROWSER": "firefox" } } } }

Tools

`open_folder`

Opens a folder in the system file manager.

Parameters:

path (string, required): Absolute or relative path to the folder

Example:

{ "path": "/home/user/Documents" }

Behavior by Platform:

Linux: Uses xdg-open, falls back to nautilus or dolphin
macOS: Uses open (Finder)
Windows: Uses explorer

`open_file`

Opens a file with its default application.

Parameters:

path (string, required): Absolute or relative path to the file

Example:

{ "path": "./report.pdf" }

Behavior by Platform:

Linux: Uses xdg-open
macOS: Uses open
Windows: Uses start

`open_browser`

Opens a URL in the preferred web browser.

Parameters:

url (string, required): URL to open (must start with http://, https://, or file://)

Example:

{ "url": "https://github.com" }

Behavior:

Checks configured browser preference (MCP_OPENER_BROWSER)
On Linux with Firefox:
- Auto-detects Flatpak installation
- For file:// URLs with Flatpak: Copies file to /tmp for accessibility
- Uses flatpak run org.mozilla.firefox for Flatpak
- Uses native firefox command otherwise
Falls back to system default browser if preferred browser unavailable

Special Handling for Fedora Bluefin / Flatpak Firefox:

When opening local HTML files or other file:// URLs with Flatpak Firefox:

File is copied to /tmp/mcp-opener-<random>/
Browser opens the /tmp copy
Cleanup happens after 5 seconds

This works around Flatpak's filesystem sandboxing restrictions.

Platform Support

Platform	File Manager	Browser Detection	Flatpak Support
Linux	xdg-open, Nautilus, Dolphin	✅	✅
macOS	Finder	✅	N/A
Windows	Explorer	✅	N/A

Usage Examples

From Claude Code

User: Open my Downloads folder Agent: [Uses open_folder tool with path: /home/user/Downloads] User: Open this README file Agent: [Uses open_file tool with path: ./README.md] User: Open GitHub in my browser Agent: [Uses open_browser tool with url: https://github.com] User: Preview this HTML file Agent: [Uses open_browser tool with url: file:///home/user/project/index.html] [On Flatpak Firefox: Copies to /tmp, opens copy, cleans up]

Direct Tool Calls

// Open folder { "name": "open_folder", "arguments": { "path": "/home/viky/Code" } } // Open file { "name": "open_file", "arguments": { "path": "./package.json" } } // Open browser { "name": "open_browser", "arguments": { "url": "https://anthropic.com" } }

Error Handling

The server provides detailed error messages:

File/folder not found: "File does not exist: /path/to/file"
Invalid URL: "URL must start with http://, https://, or file://"
Platform not supported: "Unsupported platform: <platform>"
No file manager found: "No file manager found (tried xdg-open, nautilus, dolphin)"

Development

# Watch mode for development pnpm dev # Build for production pnpm build # Test the server manually echo '{"method":"tools/list"}' | node dist/index.js

Troubleshooting

Flatpak Firefox not detected

Check if Firefox is installed via Flatpak:

flatpak list --app | grep firefox

If installed, you should see org.mozilla.firefox. Set MCP_OPENER_FIREFOX_FLATPAK=true explicitly if auto-detection fails.

Files not opening in Flatpak Firefox

Ensure MCP_OPENER_TMP_COPY=true (default). The server will copy files to /tmp for Flatpak accessibility.

Wrong browser opens

Set MCP_OPENER_BROWSER explicitly:

MCP_OPENER_BROWSER=firefox # or MCP_OPENER_BROWSER=chrome # or MCP_OPENER_BROWSER=default

License

MIT

Author

3viky

Contributing

Issues and PRs welcome at github.com/3viky/mcp-opener

MCP Opener

MCP Opener

Features

Installation

Configuration

Claude Code Configuration

Tools

`open_folder`

`open_file`

`open_browser`

Platform Support

Usage Examples

From Claude Code

Direct Tool Calls

Error Handling

Development

Troubleshooting

Flatpak Firefox not detected

Files not opening in Flatpak Firefox

Wrong browser opens

License

Author

Contributing

Resources

Tools

New MCP Servers

Latest Blog Posts

MCP directory API