The open-source browser your AI agent can drive.
A Chromium sidebar browser for macOS with a built-in MCP server. Claude, Cursor or any MCP client browses in the same window you do, logins and all. Open source, so nobody can shelve it.
Also: Apple Silicon · Intel
Illustration: cards an agent sends with ask_user / notify_user.
Roar⚙︎See Roar in one minute
Watch an agent work
A scripted illustration of what an MCP agent can do in Roar. Left: your agent (here Claude Code). Right: Roar, where it works. Pick a job, or answer its question yourself in Roar’s sidebar.
RoarInstall
About five minutes, start to finish. Needs a Mac on macOS 13 or later; no Node.js.
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Download 1 min
Get the latest DMG, open it and drag Roar onto Applications. Or use Homebrew:
brew install --cask roarbrowser/tap/roar -
First open
Roar is signed and notarized by Apple, so it opens like any app you download: macOS asks once whether to open it. Click Open.
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Connect your agent 1 min
Roar's welcome page has a Connect button for Claude Code, Claude Desktop, Cursor, VS Code, Windsurf, Codex, Gemini CLI and others. Click yours, then restart that app. The server ships inside Roar and launches Roar if it isn't running (keep Allow agents to connect on).
Set it up by hand
The server is
/Applications/Roar.app/Contents/Resources/roar-mcp, a stdio MCP server.Claude Code
claude mcp add --scope user roar -- /Applications/Roar.app/Contents/Resources/roar-mcpCodex
codex mcp add roar -- /Applications/Roar.app/Contents/Resources/roar-mcpGemini CLI
gemini mcp add roar /Applications/Roar.app/Contents/Resources/roar-mcpVS Code
code --add-mcp '{"name":"roar","command":"/Applications/Roar.app/Contents/Resources/roar-mcp"}'Claude Desktop, Cursor, Windsurf and most others
Add this to the client's MCP config:
~/Library/Application Support/Claude/claude_desktop_config.json,~/.cursor/mcp.jsonor~/.codeium/windsurf/mcp_config.json.{ "mcpServers": { "roar": { "command": "/Applications/Roar.app/Contents/Resources/roar-mcp" } } }
What's inside
What your agent gets
- Real tabsPages your agent opens land in your sidebar. Watch, take over or close them.
- It asks you firstCards in the sidebar; your click goes back to the agent.
- Your sessions, beside your tabsSee each Claude Code session, reply, or send it the page you’re on.
- Only where you allowOne click on the sidebar dot blocks the space you’re in. Ghost tabs are always off-limits.
- Headless if you’d ratherAgents can use a hidden Roar with its own profile.
What you get
- Spaces in a vertical sidebarEach space has its own tabs and its own logins.
- Pinned tabs, groups and split viewTwo tabs side by side when you need them.
- Tabs that tidy themselvesThey archive after 6 hours to a week.
- Command bar and reader mode⌘T searches tabs, history and page text. uBlock Origin Lite is built in.
- Leave Arc in one stepYour spaces and pinned tabs come over on first launch. Chrome, Safari, Firefox, Edge and Dia import too.
Roar vs the rest
The new AI browsers ship their own assistant and keep the source closed. Roar is the other answer: MIT licensed, no built-in assistant, and your own agent plugged in over MCP.
| Browser | Open source | Built-in AI | Your agent can drive it | Vertical tabs |
|---|---|---|---|---|
| Roar | Yes, MIT | None. Bring your own | Yes, built-in MCP server | Yes, with spaces |
| AI browsers | ||||
| Dia | No | Dia's assistant | No official MCP path | Optional, since July 2025 |
| ChatGPT Atlas | No | ChatGPT | No official MCP path | Had them; OpenAI shut Atlas down Aug 9, 2026 |
| ChatGPT desktop app | No | ChatGPT | — | — |
| Perplexity Comet | No | Perplexity | No official MCP path | — |
| Genspark | No | Genspark | — | — |
| Opera Neon | No | Neon AI, paid plan | Yes, MCP Connector | — |
| Everyday browsers | ||||
| Chrome | No, only Chromium is | Gemini | Separate setup (chrome-devtools-mcp) | Optional, since April 2026 |
| Edge | No | Copilot | No official one | Optional, since 2021 |
| Brave | Yes, MPL 2.0 | Leo | No, community add-ons only | Optional, since 2023 |
| Firefox | Yes, MPL 2.0 | Chatbot sidebar, your pick of provider | No | Optional, since March 2025 |
| Safari | No | Apple Intelligence | No | No |
Checked October 17, 2026. A dash means we couldn't confirm it from the maker or the press.
Sources
- Dia vertical tabs: AlternativeTo, July 8, 2025
- ChatGPT Atlas vertical tabs: MacRumors, November 20, 2025; shutdown, folded into the ChatGPT desktop app: 9to5Mac, July 9, 2026
- Genspark: genspark.ai
- Comet: perplexity.ai/comet
- Opera Neon MCP Connector, free plan: Opera, August 12, 2026
- Chrome vertical tabs: Google, April 7, 2026; chrome-devtools-mcp: GitHub
- Edge vertical tabs: Microsoft
- Brave license: GitHub; vertical tabs: Brave, May 31, 2023
- Firefox vertical tabs: Firefox 136 release notes, March 4, 2025
We don't need a browser company to build a browser.