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Firefox DevTools MCP Server

Firefox browser automation via WebDriver BiDi for AI development workflows.

Data last scanned today · Reviewed today

20 5 dangerous tools58 tools★ 401TypeScriptNOASSERTION

Overview

This MCP server enables AI assistants to control and automate a local Firefox browser instance using the WebDriver BiDi protocol. It supports various tool presets ranging from basic navigation to advanced debugging, network inspection, and privileged Mozilla-specific browser access. Designed for local execution, the server requires a Firefox 100+ installation and Node.js 20.19.0 or later. Users can deploy it via npx or Docker, with the ability to configure browser behavior through CLI arguments and environment variables like headless mode and custom viewport sizes.

Our verdict

With a security score of 45/100, this server is classified as high risk. Because the authentication method and read-only mode support remain unreviewed, users must follow strict safety protocols, including the use of a dedicated Firefox profile and limiting tool presets to only what is necessary for their specific task. This tool is best suited for experienced developers working in controlled, local environments who are prepared to manage the browser isolation themselves.

Supports modular tool presets to limit agent access levels.
Small dependency surface with only 5 direct dependencies.
Maintains active development with recent commit activity.

High-risk security score due to unreviewed authentication mechanisms.
Requires manual isolation via dedicated browser profiles.
License status listed as NOASSERTION in data.

Setup

Claude Desktop

{
  "mcpServers": {
    "firefox-devtools-mcp": {
      "args": [
        "-y",
        "@mozilla/firefox-devtools-mcp"
      ],
      "command": "npx"
    }
  }
}

Paste into ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows), then restart Claude Desktop. Some servers require API keys or tokens as environment variables — check the project's README and add an "env" object if needed.

No read-only mode — running this grants full read/write access.
No built-in authentication — anyone with access to this config can invoke every tool it exposes.

Tools

Tool	Description	Risk
list_pages	List open pages	low
new_page	Create a new page	medium
navigate_page	Navigate page to a URL	medium
select_page	Select a page as current	low
close_page	Close a page	medium
get_page_text	Get text content of the page	low
take_snapshot	Take a DOM snapshot	low
resolve_uid	Resolve a UID to an element	low
clear_snapshot	Clear the current DOM snapshot	low
click	Click an element by UID	medium

Compatibility

Client	Local	Docker	Remote	Read-only
Claude Desktop
Cursor
VS Code
Windsurf
ChatGPT

Frequently asked questions

›Can I run this MCP server on cloud hosting?

No, this server requires a local Firefox browser installation and cannot operate on cloud hosting services.

›What are the core system requirements?

You must have Node.js version 20.19.0 or higher and Firefox 100 or later installed on your machine.

›How should I handle Firefox profiles for security?

It is highly recommended to use a dedicated Firefox profile for this server, as the agent has access to any information reachable by the browser, such as cookies and saved sessions.

›Can I limit the tools available to the agent?

Yes, you can use the --tool-preset flag to restrict capabilities. For example, the slim preset disables evaluate_script, while developer or mozilla presets grant additional debugging or system-level access.

›Is it possible to connect to an existing Firefox instance?

Yes, you can use the --connect-existing flag to attach to a running Firefox instance instead of having the server launch a new one.