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freema/firefox-devtools-mcp

v0.9.0 Breaking

This release includes 2 breaking changes for platform teams planning a safe upgrade.

Published 2mo MCP Browser & Automation
✓ No known CVEs patched
Read the diff → Tool health → What is this tool? →

✓ No known CVEs patched in this version

Topics

claude-code firefox mcp mcp-server

Affected surfaces

auth rbac

Summary

AI summary

Script evaluation and privileged contexts now require opt‑in flags, and non‑English docs were removed.

Full changelog

What's Changed

New Features

  • Content script evaluation — evaluate JS against web pages (--enable-script flag)
  • Privileged context support — chrome-privileged context for Firefox internal development (--enable-privileged-context flag)
  • WebExtension tools — install, uninstall, and list Firefox extensions
  • Firefox restart tool — restart Firefox with new config at runtime (preserves profile path)
  • Preferences configuration — read/write Firefox prefs via CLI (--pref name=value) and runtime tools (set_firefox_prefs, get_firefox_prefs)
  • Environment variables & output capture — --env and --output-file CLI flags
  • WebDriver BiDi commands — direct support for sending BiDi commands
  • MOZ_LOG support — Firefox logging integration

Fixes

  • Use native --profile arg for reliable profile loading
  • Wait for WebSocket ready before sending BiDi commands
  • Fix pref tools failing when env var passed via --env
  • Handle disconnected Firefox gracefully in restart_firefox
  • Don't kill unrelated Firefox processes on test cleanup

Breaking Changes

  • Script evaluation and privileged context are now opt-in via --enable-script and --enable-privileged-context flags
  • Removed non-English documentation files

Contributors

  • @padenot
  • @dmose
  • @Majdoddin
  • @juliandescottes
  • @freema

Full Changelog: https://github.com/mozilla/firefox-devtools-mcp/compare/0.8.1...0.9.0

Breaking Changes

  • Script evaluation (`--enable-script`) and privileged context (`--enable-privileged-context`) are now opt‑in only
  • Removed all non‑English documentation files
View diff on GitHub

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About freema/firefox-devtools-mcp

Firefox browser automation via WebDriver BiDi for testing, scraping, and browser control. Supports snapshot/UID-based interactions, network monitoring, console capture, and screenshots.

All releases →

Related context

Beta — feedback welcome: [email protected]