Ghostty-based macOS terminal with vertical tabs and notifications for AI coding agents https://cmux.com
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Lawrence Chen 9af7df0dac Fix socket accept loop not restarted after Sparkle update relaunch
After a Sparkle auto-update relaunches cmux, the control socket stops
accepting connections because start() early-returns when isRunning is
true, without checking if the accept loop thread is actually alive.

- Add acceptLoopAlive flag to track accept loop thread liveness
- Fix start() early-return to also check acceptLoopAlive, so a dead
  thread triggers full socket re-creation
- Break acceptLoop() after 50 consecutive accept() failures with 10ms
  backoff instead of tight-spinning forever
- Clean up socket in applicationWillTerminate and
  updaterWillRelaunchApplication for clean teardown before relaunch
2026-02-17 22:00:47 -08:00
.claude/commands Add /release-local skill and direnv setup 2026-02-17 21:33:11 -08:00
.github/workflows Fix menubar lag in production builds caused by hardened runtime 2026-02-16 03:26:33 -08:00
Assets.xcassets Add dev build branding and reload scripts 2026-01-28 01:20:48 -08:00
CLI Add sidebar metadata (git branch, ports, logs, progress), fix localhost URL resolution, simplify analytics 2026-02-16 02:46:39 -08:00
docs Fix frozen terminals after split churn (#12) 2026-02-13 16:45:31 -08:00
docs-site Reversion all 1.x.x to 0.x.x for pre-launch versioning 2026-02-17 18:31:05 -08:00
ghostty@eac00f33d6 Update submodules: ghostty merge fork + upstream, homebrew cask bumps 2026-02-17 21:51:39 -08:00
GhosttyTabs.xcodeproj Bump version to 0.39.0 2026-02-17 18:43:23 -08:00
GhosttyTabsTests Browser searchbar bugs (#51) 2026-02-17 16:26:42 -08:00
GhosttyTabsUITests Fix flaky WebKit escape focus tests on slow environments (#57) 2026-02-17 21:12:28 -08:00
homebrew-cmux@796498b5aa Update submodules: ghostty merge fork + upstream, homebrew cask bumps 2026-02-17 21:51:39 -08:00
node_modules Update app and tooling 2026-01-29 17:36:26 -08:00
Resources Fix terminal keys swallowed after opening browser (#45) 2026-02-17 03:21:08 -08:00
scripts reload: quiet xcodebuild output, save full log to /tmp/cmux-xcodebuild-{tag}.log 2026-02-17 21:33:11 -08:00
skills Add sidebar metadata (git branch, ports, logs, progress), fix localhost URL resolution, simplify analytics 2026-02-16 02:46:39 -08:00
Sources Fix socket accept loop not restarted after Sparkle update relaunch 2026-02-17 22:00:47 -08:00
tests Release v1.36.0 (#47) 2026-02-17 04:04:29 -08:00
tests_v2 Fix frozen terminals after split churn (#12) 2026-02-13 16:45:31 -08:00
vendor Always show close button on active tab 2026-02-17 21:33:11 -08:00
web Browser searchbar bugs (#51) 2026-02-17 16:26:42 -08:00
.gitignore Add /release-local skill and direnv setup 2026-02-17 21:33:11 -08:00
.gitmodules Fix frozen terminals after split churn (#12) 2026-02-13 16:45:31 -08:00
.vercelignore Add Vercel ignore 2026-01-29 17:50:35 -08:00
AGENTS.md agents 2026-01-22 03:18:02 -08:00
bun.lock Update app and tooling 2026-01-29 17:36:26 -08:00
CHANGELOG.md Reversion all 1.x.x to 0.x.x for pre-launch versioning 2026-02-17 18:31:05 -08:00
CLAUDE.md Reversion all 1.x.x to 0.x.x for pre-launch versioning 2026-02-17 18:31:05 -08:00
cmux-Bridging-Header.h Rename to cmux and add About panel 2026-01-26 03:05:03 -08:00
cmux.entitlements Fix menubar lag in production builds caused by hardened runtime 2026-02-16 03:26:33 -08:00
CONTRIBUTING.md Add nightly update channel workflow and adopt AGPL licensing 2026-02-14 02:43:03 -08:00
ghostty.h Initial commit: macOS terminal app with vertical tabs using libghostty 2026-01-22 01:16:24 -08:00
LICENSE Add nightly update channel workflow and adopt AGPL licensing 2026-02-14 02:43:03 -08:00
package.json Add nightly update channel workflow and adopt AGPL licensing 2026-02-14 02:43:03 -08:00
Package.resolved Initial commit: macOS terminal app with vertical tabs using libghostty 2026-01-22 01:16:24 -08:00
Package.swift Rename to cmux and add About panel 2026-01-26 03:05:03 -08:00
PROJECTS.md Reversion all 1.x.x to 0.x.x for pre-launch versioning 2026-02-17 18:31:05 -08:00
README.ar.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.bs.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.da.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.de.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.es.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.fr.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.it.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.ja.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.ko.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.no.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.pl.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.pt-BR.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.ru.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.th.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.tr.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.zh-CN.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
README.zh-TW.md update keyboard shortcuts in README and translations 2026-02-15 21:49:54 -08:00
THIRD_PARTY_LICENSES.md add third-party licenses and update bonsplit submodule 2026-02-14 20:33:40 -08:00
TODO.md Update TODO with bugs, refactoring items, and UI improvements 2026-02-17 18:45:38 -08:00

cmux

A Ghostty-based macOS terminal with vertical tabs and notifications for AI coding agents

Download cmux for macOS

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cmux screenshot

Features

  • Vertical tabs — Sidebar shows git branch, working directory, listening ports, and latest notification text
  • Notification rings — Panes get a blue ring and tabs light up when AI agents (Claude Code, OpenCode) need your attention
  • Notification panel — See all pending notifications in one place, jump to the most recent unread
  • Split panes — Horizontal and vertical splits
  • In-app browser — Split a browser alongside your terminal with a scriptable API ported from agent-browser
  • Scriptable — CLI and socket API to create workspaces, split panes, send keystrokes, and automate the browser
  • Native macOS app — Built with Swift and AppKit, not Electron. Fast startup, low memory.
  • Ghostty compatible — Reads your existing ~/.config/ghostty/config for themes, fonts, and colors
  • GPU-accelerated — Powered by libghostty for smooth rendering

Install

Download cmux for macOS

Open the .dmg and drag cmux to your Applications folder. cmux auto-updates via Sparkle, so you only need to download once.

Homebrew

brew tap manaflow-ai/cmux
brew install --cask cmux

To update later:

brew upgrade --cask cmux

On first launch, macOS may ask you to confirm opening an app from an identified developer. Click Open to proceed.

Why cmux?

I run a lot of Claude Code and Codex sessions in parallel. I was using Ghostty with a bunch of split panes, and relying on native macOS notifications to know when an agent needed me. But Claude Code's notification body is always just "Claude is waiting for your input" with no context, and with enough tabs open I couldn't even read the titles anymore.

I tried a few coding orchestrators but most of them were Electron/Tauri apps and the performance bugged me. I also just prefer the terminal since GUI orchestrators lock you into their workflow. So I built cmux as a native macOS app in Swift/AppKit. It uses libghostty for terminal rendering and reads your existing Ghostty config for themes, fonts, and colors.

The main additions are the sidebar and notification system. The sidebar has vertical tabs that show git branch, working directory, listening ports, and the latest notification text for each workspace. The notification system picks up terminal sequences (OSC 9/99/777) and has a CLI (cmux notify) you can wire into agent hooks for Claude Code, OpenCode, etc. When an agent is waiting, its pane gets a blue ring and the tab lights up in the sidebar, so I can tell which one needs me across splits and tabs. Cmd+Shift+U jumps to the most recent unread.

The in-app browser has a scriptable API ported from agent-browser. Agents can snapshot the accessibility tree, get element refs, click, fill forms, and evaluate JS. You can split a browser pane next to your terminal and have Claude Code interact with your dev server directly.

Everything is scriptable through the CLI and socket API — create workspaces/tabs, split panes, send keystrokes, open URLs in the browser.

Keyboard Shortcuts

Workspaces

Shortcut Action
⌘ N New workspace
⌘ 18 Jump to workspace 18
⌘ 9 Jump to last workspace
⌃ ⌘ ] Next workspace
⌃ ⌘ [ Previous workspace
⌘ ⇧ W Close workspace
⌘ B Toggle sidebar

Surfaces

Shortcut Action
⌘ T New surface
⌘ ⇧ ] Next surface
⌘ ⇧ [ Previous surface
⌃ Tab Next surface
⌃ ⇧ Tab Previous surface
⌃ 18 Jump to surface 18
⌃ 9 Jump to last surface
⌘ W Close surface

Split Panes

Shortcut Action
⌘ D Split right
⌘ ⇧ D Split down
⌥ ⌘ ← → ↑ ↓ Focus pane directionally
⌘ ⇧ H Flash focused panel

Browser

Shortcut Action
⌘ ⇧ L Open browser in split
⌘ L Focus address bar
⌘ [ Back
⌘ ] Forward
⌘ R Reload page
⌥ ⌘ I Open Developer Tools

Notifications

Shortcut Action
⌘ I Show notifications panel
⌘ ⇧ U Jump to latest unread

Find

Shortcut Action
⌘ F Find
⌘ G / ⌘ ⇧ G Find next / previous
⌘ ⇧ F Hide find bar
⌘ E Use selection for find

Terminal

Shortcut Action
⌘ K Clear scrollback
⌘ C Copy (with selection)
⌘ V Paste
⌘ + / ⌘ - Increase / decrease font size
⌘ 0 Reset font size

Window

Shortcut Action
⌘ ⇧ N New window
⌘ , Settings
⌘ ⇧ , Reload configuration
⌘ Q Quit

License

This project is licensed under the GNU Affero General Public License v3.0 or later (AGPL-3.0-or-later).

See LICENSE for the full text.