// SPDX-License-Identifier: AGPL-3.0-or-later = Claude Firefox MCP :toc: :icons: font

MCP (Model Context Protocol) server that enables Claude Code CLI to control Firefox browser.

== Overview

This project bridges Claude Code and Firefox, allowing Claude to:

• Take screenshots
• Navigate to URLs
• Read page content (accessibility tree)
• Click elements
• Type text
• Fill forms
• Manage tabs

== Architecture

[source]

┌─────────────┐ stdio ┌──────────────────┐ WebSocket ┌─────────────────┐ │ Claude Code │ ◄────────────► │ MCP Server │ ◄───────────► │ Firefox │ │ CLI │ (MCP) │ (Deno) │ (localhost) │ Extension │ └─────────────┘ └──────────────────┘ └─────────────────┘

== Requirements

• https://deno.land[Deno] runtime
• Firefox 78+
• Claude Code CLI

== Installation

[source,bash]

Clone

git clone https://github.com/hyperpolymath/claude-firefox-mcp.git cd claude-firefox-mcp

Install

./scripts/install.sh

=== Load Firefox Extension

1. Open Firefox and go to about:debugging
2. Click "This Firefox"
3. Click "Load Temporary Add-on"
4. Select extension/manifest.json

=== Configure Claude Code

Add to ~/.claude/settings.json:

[source,json]

{ "mcpServers": { "firefox": { "command": "claude-firefox-mcp", "args": [] } } }

== Available Tools

[cols="1,2"] |=== |Tool |Description

|screenshot |Capture current tab as PNG

|navigate |Go to URL, or 'back'/'forward'

|read_page |Get accessibility tree of page elements

|click |Click at [x, y] coordinates

|type |Type text into focused element

|scroll |Scroll up/down/left/right

|execute_js |Run JavaScript in page context

|find |Find elements by text or CSS selector

|form_input |Set form field value

|tabs_list |List open tabs

|tabs_create |Create new tab

|tabs_close |Close a tab

|get_page_text |Get page text content |===

== Usage Example

Once configured, Claude Code can control Firefox:

[source]

User: Open Firefox and search for "Deno runtime"

Claude: I'll navigate to Google and search for that. [uses navigate tool to go to google.com] [uses type tool to enter search query] [uses click tool to click search button]

== Development

=== Run Server Manually

[source,bash]

deno run --allow-net --allow-read --allow-env host/server.ts

=== Extension Development

The extension auto-reconnects to the MCP server. Click the extension icon to manually trigger reconnection.

== Comparison with Claude in Chrome

[cols="1,1,1"] |=== |Feature |Claude Firefox MCP |Claude in Chrome

|Browser |Firefox, Thunderbird, SeaMonkey |Chrome only

|Protocol |MCP over stdio + WebSocket |MCP over native messaging

|Code |~800 LOC |Proprietary

|License |AGPL-3.0-or-later |Proprietary |===

== License

AGPL-3.0-or-later

This is an independent project. Not affiliated with Anthropic or Mozilla.