cmux Release Notes

Try itRun cmux ssh user@host to open a workspace on the remote machine.

Steady Agent Layouts

Agents resumed with cmux restore or cmux fork receive terminal resizes again, so their layout no longer garbles after a restore. Images dropped or pasted into a terminal stay on disk long enough for Claude Code and Codex to read them.

Try itRun cmux restore --surface <ref> or cmux fork --surface <ref> on a saved agent session, then resize its pane.

Light Mode Terminals

A terminal no longer reloads its dark theme after macOS switches to light, and Light applies the light palette when the Ghostty config sets only a font, keybinding, or opacity.

Try itSet Settings > App > Appearance to System, then switch macOS to Light.

Changed

• The persistent "Terminal is not rendering" banner no longer covers terminal panes; render-health recovery, logs, and socket fields are unchanged (#12738).

Fixed

• SSH workspaces connect again in released builds: the app ships a checksum-verified cmuxd-remote for macOS and Linux, and the release pipeline rejects a build whose daemon manifest and assets disagree (#12720) -- thanks @john-agi for the report! …

Agents over SSH, Crash Recovery, Predictive Echo, Settings Redesign, Terminal Import

Agents on SSH Hosts

Claude Code and Codex on a cmux ssh host show Running, Needs input, or Idle in the sidebar, like local agents. A stopped Claude Code session can move between your Mac and a host with its transcript and git working tree.

Try itRun cmux session move <session-id> --to user@host.

Predictive Local Echo

Over a slow remote link, the characters you type appear right away, underlined until the remote shell confirms them. It is on by default for remote terminals.

Try itSettings > Terminal > Predictive Local Echo.

Crash-Proof Sessions

Terminal scrollback is checkpointed, and interrupted Claude sessions can be recovered after a crash. Agents whose turn ends on a retryable error, such as model capacity or a dropped connection, are told to continue automatically.

Try itRun cmux session restore to bring back interrupted agent sessions.

Redesigned Settings

Settings shows one categorized section at a time, with a theme gallery and controls for Ghostty fonts, cursor, and opacity.

Try itOpen Settings with ⌘, and pick a section from the sidebar.

Bring Your Terminal Setup

Import settings from iTerm2, Terminal, Alacritty, Kitty, WezTerm, or Warp, and pick a Base Keymap preset that matches the shortcuts you already know.

Try itRun cmux import, or open Settings > Keyboard Shortcuts.

Jump to Your Prompts …

<!-- cmux-published-sha: c79bb22e6862d729bc9edbbb1a442e0ace1ade4a -->

Automated nightly build for c79bb22 from nightly-next. Published commit: c79bb22e6862d729bc9edbbb1a442e0ace1ade4a. cmux NIGHTLY ships one app per architecture (bundle ID com.cmuxterm.app.nightly):

• Apple silicon: cmux-nightly-next-macos-arm64.dmg, feed appcast-arm64.xml
• Intel: cmux-nightly-next-macos-x86_64.dmg, feed appcast-x86_64.xml
• Universal (any Mac): cmux-nightly-next-macos.dmg, feed appcast.xml; the app switches to its architecture's feed on the first update check

<!-- cmux-published-sha: 77eea5fafab1ef09ccb40fb8c5a62c52ec76bee1 -->

Automated rc build for 77eea5f from rc/v0.65.0. Published commit: 77eea5fafab1ef09ccb40fb8c5a62c52ec76bee1. cmux RC ships one app per architecture (bundle ID com.cmuxterm.app.rc):

• Apple silicon: cmux-rc-macos-arm64.dmg, feed appcast-arm64.xml
• Intel: cmux-rc-macos-x86_64.dmg, feed appcast-x86_64.xml
• Universal (any Mac): cmux-rc-macos.dmg, feed appcast.xml; the app switches to its architecture's feed on the first update check

Reliable Codex Resumes, Account Switching, Cloud CLI Compatibility

Reliable Codex Resumes

Codex --yolo no longer calls a missing helper or replays a restore command after repeated resume cycles, keeping the active session identity attached to the right terminal.

Switch CLI Accounts

The CLI authorization page can sign out the current browser account and return to sign-in with the original confirmation code intact.

Cloud CLI Compatibility

Cloud terminal sessions accept the workspace-close syntax used by the in-terminal CLI while preserving routing, JSON output, revision fences, and idempotency.

Added

• IROH v2 Cloud connectivity now uses the Cloudflare control plane with durable pairing, relay renewal, direct-only routes, and recovery that stays alive through stalls and traffic bursts (#12326, #12411) -- thanks @azooz2003-bit!
• Cloud file transfers use private SCP, and iOS Computer details can delete non-IROH routes without losing the computer (`5f0ce77`, #12691) -- thanks @azooz2003-bit!

Changed …

Vault Search and Checkpoints, Inline Notification Replies, Nine Languages

Vault Search, Checkpoints, and Fork

Every agent session lands in a recency-first Vault with day sections and filters, search with agent:, repo:, ws:, before:, and after: operators, and checkpoints you can fork from for Claude Code, Codex, Pi, and Grok, in the app or through cmux vault and cmux fork.

Reply to Agents from Notifications

Answer an agent straight from the macOS banner or the iPhone Lock Screen: type a reply on turn-complete and idle notifications, pick an option on AskUserQuestion banners, or send a revision on exit-plan banners. Automations, agent-event context for notification hooks, and per-agent sounds round out the pipeline.

cmux in Nine Languages

The macOS app is fully localized in German, French, Spanish, Arabic, Korean, Simplified and Traditional Chinese, and Japanese alongside English.

More Agents, More Shells

Amp and Hermes join Claude Code, Codex, Pi, and Grok as first-class agents with auto-resume, notifications, and Vault history, Cursor approvals show up as Needs input, and Nushell gets shell integration and session resume.

Stability and Performance

Workspace switching no longer ghosts or hangs, idle CPU burn from logging and git watchers is gone, terminals in hidden windows release about 40 MB each, persistent SSH reconnects survive sleep and network changes, and Google Sheets no longer pins a core. …

Fixed

• Fix a crash seconds after launch on Intel Macs; cmux is now the only process-wide crash handler, and embedded GhosttyKit no longer links Ghostty's native Sentry initializer (#9436)
• Fix cmux ssh <host> failing immediately with a shell syntax error from the generated startup script (#9425) -- thanks @KousukeUchiyama for the report!
• Clear Dock notifications when you focus the pane that raised them (#9418)
• Keep a restored Claude agent on its own account instead of falling back to the ambient one (#9419) -- thanks @seanyoungberg for the report!
• Stop bash shell integration printing cannot overwrite existing file on every prompt under set -o noclobber (#9420) -- thanks @8bit-void for the report!
• Fail closed when close or respawn-pane is given an explicit --surface that no longer exists, instead of acting on a different live surface (#9422) -- thanks @PhilipPinckaers for the report!

Contributors …

Simulator Panes, Mosh Transport, Idle CPU Reclaimed

Native Simulator Panes

Run iPhone and iPad Simulators as first-class cmux panes, rendered crisply at real size, with their own commands and automation so an agent can drive the simulator next to the terminal that built it.

Mosh for Remote Workspaces

Remote workspaces can use Mosh instead of plain SSH, so a laptop that sleeps, changes networks, or loses Wi-Fi picks the session back up instead of dropping it.

Idle CPU and Memory Reclaimed

Leaked openThread loops that burned about 90% of cmux idle CPU are gone, hidden Ghostty renderers release their memory, workspace switching no longer freezes the renderer, and idle background agents hibernate under critical memory pressure.

Navigation and Restore

Cmd+Shift+T reopens the last closed item, Cmd+[ and Cmd+] walk global workspace focus history, surfaces move between panes with automatic directional splits, and Dock panes, workspace IDs, and per-tab terminal zoom all survive a restart.

cmux on iPhone (beta)

Stream Mac browser panes to the phone interactively, follow a chronological notification feed, launch agent workspaces from the task composer, and scroll terminals locally on screen-anchored render grids over a rebuilt peer-to-peer transport.

Added

• Native iPhone and iPad Simulator panes, with their own commands and automation (#7857) …

Native AppKit Sidebar, Browser Design Mode, TUI Mouse Forwarding

Native AppKit Sidebar

The workspace sidebar is rebuilt on native AppKit rows and is now on by default: faster scrolling in large workspace lists, precise hover and selection, and full fidelity with your sidebar settings.

Browser Design Mode

Visually edit pages inside the browser pane, annotate elements, and hand the annotated changes straight to an agent to implement.

Mouse Input for TUI Apps

cmux now forwards mouse input to TUI applications running in the terminal, so tools that own the pointer respond to clicks, drags, and scrolls as expected.

Stability and Performance

Codex YOLO mode and Pi sessions survive restore, typing latency from title churn is fixed, sidebar scroll livelocks and popover resize crashes are gone, and remote ssh-tmux panes size and focus correctly.

Added

• Native AppKit workspace sidebar, now on by default: faster scrolling, precise hover and selection, and full settings fidelity (#8270, #8433, #8366, #8390, #8415, #8432, #8450) -- thanks @azooz2003-bit! …

Fixed

• Fix overflowed tab bar scrolling to the wrong place, right-edge tabs hiding their close buttons, and a misaligned active-tab indicator (#8071)
• Preserve the Claude Code permission mode when restoring, resuming, or forking a session, including interactively chosen auto-accept/plan/bypass modes; stop a one-word prompt after a boolean flag from being replayed on resume (#8070)

Contributors

austinywangaustinywang

Saved Workspace Layouts, Fork Conversation, Per-Monitor Window Memory

Saved Workspace Layouts

Capture the current split arrangement as a named layout, reopen it from the new-workspace menu anytime, and set a default layout that every new workspace starts from.

Fork Conversation

Right-click an agent terminal to fork the conversation into a new split, tab, or workspace, so you can explore a tangent without losing the original session.

Per-Monitor Window Memory

cmux remembers window position and size per monitor configuration and refits windows when displays change, so docking and undocking a laptop no longer scrambles your setup.

Stability and Performance

A coordinated memory-pressure response with automatic scrollback compression, fixes for macOS 27 launch crashes and SSH panes dying after sleep, runaway scrolling with high-resolution mice, and a Sparkle update that no longer kills running agents on macOS 26.

Added

• Saved workspace layouts: capture the current split arrangement as a named layout, reopen it from the + menu, and set a default layout for new workspaces (#7414, #7354) -- thanks @azooz2003-bit!
• Fork Conversation from an agent terminal's context menu into a new split, tab, or workspace (#7259) …

Added

• Vault: recency-first All Sessions view with day sections and filters, session search with agent:, repo:, ws:, before:, and after: operators, and checkpoints with fork-from-checkpoint for Claude Code, Codex, Pi, and Grok, plus cmux vault sessions|search|checkpoints|checkpoint|fork and cmux fork <kind> <checkpoint> (#10215, #11324); session status dots and a native search field shared with Find (#11915, #12146, #12036, #12109)
• Reply to agent notifications inline from the macOS banner: typed replies on turn-complete and idle notifications, one button per option on AskUserQuestion banners, and Revise… on exit-plan banners; cmux notify --reply marks a notification replyable (#8670, #10511) -- thanks @azooz2003-bit! …