Firefox DevTools MCP

Model Context Protocol server for automating Firefox via WebDriver BiDi (through Selenium WebDriver). Works with Claude Code, Claude Desktop, Cursor, Cline and other MCP clients. Its 4 documented tools cluster into slim, developer, mozilla, all. It runs locally over stdio via the published package.

People who work with Start and Firefox and want it reachable from Claude, Cursor, VS Code, or another MCP client. The project is written in TypeScript.

VERIFIED ACTIVE

LAST COMMIT 2026-09-28 · ★ 451 · #11 OF 290 MAINTAINED BROWSER AUTOMATION · VERIFIED 2026-09-30

NOASSERTION · TypeScript servers · how we verify → /methodology

01 · Install Firefox DevTools MCP

before you install - you'll need

Set START_URL, FIREFOX_HEADLESS before connecting.

Claude Code

claude mcp add mozilla-firefox-devtools-mcp -- npx -y @mozilla/firefox-devtools-mcp

Claude Desktop / Cursor / VS Code - add to config

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

Same JSON for Cursor. For VS Code, rename the top-level key from `mcpServers` to `servers`.

Using another client? Same JSON, different key

Claude Desktop · mcpServers

Cursor · mcpServers

VS Code · servers

Windsurf · mcpServers

Zed · context_servers

Cline · mcpServers

Roo Code · mcpServers

Continue · mcpServers

LibreChat · mcpServers

Gemini CLI · mcpServers

Codex CLI · mcp_servers

Full setup guides: every client.

02 · Evidence

Security posture

What to check before giving this server access to your agent - from the registry, GitHub, and our own probes. We don't score safety; we show what's verifiable.

runs as local process (stdio) - runs on your machine with your user's permissions

license no standard license detected - usage rights unclear; check the repo before commercial use

npm package @mozilla/firefox-devtools-mcp - published under the repo owner's npm scope (@mozilla)

registry namespace io.github.mozilla is GitHub-verified and matches the repo owner

03 · What Firefox DevTools MCP can do

Prose above is summarized from the project's README and registry record - no invented capabilities.

What you can build

An agent gets 4 documented tools across slim, developer, mozilla, including slim, developer, mozilla, all.

Capability map

Tools grouped from the project's README - what Firefox DevTools MCP lets an agent do.

Slim

1 tool - e.g. pages, snapshot, input, screenshot

slim

Developer

1 tool - e.g. basic plus debugging, network, console, profiler

developer

Mozilla

1 tool - e.g. developer plus launch, prefs, privileged

mozilla

All

1 tool - e.g. every module

all

Latest releases

v0.10.4 · 2026-09-22

add mcp registration artifacts · prepare release v0.10.4

v0.10.3 · 2026-09-18

add webdriver-bidi-protocol types · replacing deprecated server with McpServer · bypass Selenium Manager only where it cannot run · Bug 2071202 - [firefox-devtools-mcp] Add tool to close the browser session (close or…

v0.10.2 · 2026-09-04

enforce LF line endings with gitattributes · Bug 2065546 - [firefox-devtools-mcp] navigate should accept an option to wait for load · make process cleanup work on Windows · handle file paths correctly on Windows…

04 · Who maintains Firefox DevTools MCP

Firefox DevTools MCP is maintained by mozilla. It's the only MCP server we track from this author; the repo dates to Oct 2025.

05 · Facts

repository: github.com/mozilla/firefox-devtools-mcp
website: https://github.com/mozilla/firefox-devtools-mcp
category: browser automation - ranked #11 of 290 actively-maintained browser automation servers as of 2026-09-30.
release cadence: 10+ releases in the last 90 days (latest 2026-09-22)
registry: io.github.mozilla/firefox-devtools-mcp (active, first published 2026-09-22)
packages: npm:@mozilla/firefox-devtools-mcp

06 · Firefox DevTools MCP FAQ

Is Firefox DevTools MCP still maintained?

Yes - as of 2026-09-30, its last commit was 2026-09-28 and it shipped 10+ releases in the last 90 days. We re-verify nightly.

What can Firefox DevTools MCP do?

An agent gets 4 documented tools across slim, developer, mozilla, including slim, developer, mozilla, all.

How do I install Firefox DevTools MCP?

Run `npx -y @mozilla/firefox-devtools-mcp`. The README documents 2 environment variables (START_URL, FIREFOX_HEADLESS) to set first. Set START_URL, FIREFOX_HEADLESS before connecting. You can also paste the ready-made client config above.

Does Firefox DevTools MCP run locally?

Yes - it's a stdio server: it runs on your machine (via npx) with your user's permissions. Your data stays local unless the server itself calls external APIs.

07 · Alternatives to Firefox DevTools MCP

Alternatives to Firefox DevTools MCP

Maintained browser automation servers if Firefox DevTools MCP isn't the fit.

Pairs well with

Servers that cover what Firefox DevTools MCP doesn't - only shown when the pairing reason fits the companion.

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