Allows interaction with Firefox via its Remote Debugging Protocol, providing tools to evaluate JavaScript, navigate tabs, capture network traffic, take screenshots, and extract page content.
Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type @ followed by the MCP server name and your instructions, e.g., "@mcp-firefox take a full page screenshot of the current tab"
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.
An MCP (Model Context Protocol) server that connects to Firefox's Remote Debugging Protocol (RDP) over TCP, exposing browser DevTools capabilities as tools for LLMs.
Firefox has a built-in Remote Debugging Protocol that speaks length-prefixed JSON over TCP. This server maintains a persistent connection to that port and translates MCP tool calls into RDP messages, returning the results to the LLM.
LLM ↔ MCP (HTTP :8090) ↔ Firefox RDP (TCP :6000)The RDP client uses a background reader task to handle both request/response pairs and unsolicited events (like network traffic), enabling real-time capture features.
Related MCP server: sa2web-mcp
Tool | Description |
| Evaluate a JavaScript expression in the current tab's console (supports top-level await) |
| List all open browser tabs with URLs and titles |
| Navigate the current tab to a URL |
| Get the full HTML source of the current page |
| Get cached console messages (errors, logs) |
| Extract readable text content from the page (strips nav, ads, boilerplate) |
| Take a screenshot — viewport, full page, or a specific CSS selector element |
| Start capturing network requests (like opening the Network tab) |
| Read captured network events (URLs, methods, status, timing, optionally bodies) |
| Stop network capture and clean up |
| Send arbitrary RDP JSON for experimentation |
Open about:config in Firefox and set:
Preference | Value | Purpose |
|
| Allow remote debug connections |
|
| Skip the "allow connection?" dialog (optional) |
|
| Enable chrome debugging |
firefox --start-debugger-server 6000This opens a TCP listener on localhost:6000. Your tabs and session restore normally.
ss -tlnp | grep 6000You should see Firefox listening on 127.0.0.1:6000.
Requires Python 3.11+. Uses uv for dependency management:
uv venv
uv pip install -e ..venv/bin/firefox-mcpThe MCP server starts on http://0.0.0.0:8090/mcp using streamable HTTP transport (stateless mode).
Variable | Default | Description |
|
| Firefox RDP host |
|
| Firefox RDP port |
{
"mcpServers": {
"firefox-devtools": {
"url": "http://localhost:8090/mcp"
}
}
}# Read article text from a news site you're logged into
> read_page
# Take a screenshot of a specific element
> screenshot(selector=".article-body")
# Full page screenshot
> screenshot(fullpage=True)Capture API traffic from web apps (streaming services, SPAs, etc.):
# Start recording network traffic
> start_capture
# Navigate to the app or trigger actions
> navigate("https://www.disneyplus.com/home")
# See what API calls were made
> read_capture
# Get response bodies (JSON payloads, manifests, etc.)
> read_capture(include_bodies=True)
# Done
> stop_capture> raw_rdp_command({"to": "root", "type": "listTabs"})
> raw_rdp_command({"to": "<consoleActor>", "type": "getCachedMessages", "messageTypes": ["PageError", "ConsoleAPI"]})Use list_tabs first to discover actor IDs, then experiment with raw_rdp_command.
This server cannot be deployed
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