Say it in the address bar.
One box takes an address, a search or a task. Start with / and it is always a task. Today's projects and your open tabs wait right below.
Agentic harness for your browser.
Claude Code and Codex already have your terminal. Serein is a native Mac browser that gives them the web, in real tabs you can watch, take over or stop.
Ask without leaving the page.
Reading docs or a stack trace? Select the part you mean and press ⌥⌘E. The task panel opens beside the page, and you see exactly what gets sent.
Watch it work.
Web tasks run in visible tabs with their own cookies. The pointer glides to each element before it acts, and you can take over at any moment.
A harness, not another assistant.
Serein has no agent of its own. It finds Claude Code, Codex, Cursor Agent, OpenCode, Command Code, Grok, Hermes Agent and Pi on your Mac and gives them tabs, tools and limits. Each keeps its own sign-in, so there is no new plan, no API key to paste and no password to hand over.
- ⌘E opens one composer. Serein picks where each request goes: an answer, research, the current page or a project. It tells you why.
- Run up to three tasks at once and keep browsing. Each one runs apart from the others, with its own permissions.
- A follow-up resumes the native Claude Code or Codex session, so you do not explain the task twice.
Give them a browser. Keep the keys.
Every task can read pages. Clicking and typing, your sign-ins, project edits and Mac actions stay off until you grant them. Stop takes a task's browser access away at once.
- On a password, payment or verification-code page, the task hands the tab straight back to you.
- Agent tabs keep their own cookies. “Use my sign-ins” is a per-task grant you can take back.
- Private windows never reach an agent.
A native Mac browser underneath.
Browse
One omnibox ranks addresses, searches, tasks, tabs, history and saved pages. Vertical or horizontal tabs, groups and side-by-side compare.
⌘T · ⌘LAsk and point
Ask about a page with your selection attached, or point at up to three elements. You always see what will be sent.
⌥⌘E · ⇧⌘EReview every edit
Each edit needs your approval. Every turn's changes are snapshotted in a private Git ref: read the diff, then undo the turn or redo it.
Allow once · Always · DenyJournal
Your day on a timeline. Describe any visit to find it again, with an index that stays on your Mac.
On-devicePasswords
Kept in your Mac's Keychain and filled only on the exact site. Serein never signs in for you.
KeychainHold to talk
Hold fn and talk into a page, the omnibox or the composer. Apple Speech transcribes on your Mac.
fnGet Serein for Mac.
Download for MacSerein runs on Macs with macOS 14 or later, on Apple Silicon and Intel. You can download it here and open it on your Mac.
- 1Open the disk image from your Downloads and drag Serein onto the Applications folder.
- 2Open Serein from Applications. It's signed with a Developer ID and notarized by Apple, so macOS only asks once whether you want to open an app downloaded from the internet. Choose Open.
- 3Follow setup. A short guide opens on first launch and every step can be skipped. It finds the agents already on your Mac, and each one signs in through its own tool.
- 4Let agents use your Mac, if you want. Setup walks you through Accessibility, Screen Recording and Automation one at a time: click Allow, turn on Serein in System Settings, and it ticks itself off. Skip it to keep agents in the browser.