cmux Skill (manaflow-ai) for Claude Code: What It Does and How to Install It

Makes Claude control the cmux terminal: windows, workspaces, panes, focus, moves and run-in-new-split commands.

Installs: 9.9K; on skills.sh
Stars: 28.6K; on GitHub
Files: 5; besides SKILL.md
Updated: Nov 2026; last repo commit

This skill teaches Claude the cmux command line. Claude can list your windows, workspaces, panes and surfaces, open splits, move and reorder them, set workspace colors and names, and flash a surface so you can see it. A new split can start with a command already running.

It needs the cmux macOS app. It is in the cmux repo itself. It bundles no scripts, only SKILL.md, 4 reference files and an openai.yaml. Claude runs cmux commands in your terminal, so approve them as you would any shell command.

Good for

cmux users who want Claude to arrange panes and workspaces
Developers running dev servers and tests in new splits through an agent
Anyone scripting a multi-pane layout

Install cmux

Claude Code

Copy this prompt.

Install the cmux skill in Claude Code. Run this command:

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

Then check that it loaded and tell me how to use it.

2
Paste it into Claude Code. It shows the change and asks before running it.

Requires Homebrew, macOS.

The skill only drives the cmux macOS app through its command line, so install the app too. The README's DMG route opens a disk image to drag cmux into Applications and auto-updates. The Homebrew cask is the other documented route. Because it runs a local CLI, there is no Claude app upload route.

From the project README. Source.

What's in the skill

When it loads

End-user control of cmux topology and routing (windows, workspaces, panes/surfaces, focus, moves, reorder, identify, trigger flash). Use when automation needs deterministic placement and navigation in a multi-pane cmux layout.

Sections in SKILL.md

Fast start
Handle model
Initial command on new terminals
Settings
Deep-dive references

Key facts

Author: manaflow-ai (the cmux maker; this is the skill in cmux's own repo)
License: NOASSERTION in the crawl; README says GPL-3.0-or-later (server software under BSL 1.1)
Installs on skills.sh: 9,869 (Nov 2, 2026)
GitHub stars: 28,635 for the whole cmux repo (Nov 2, 2026)
Last repo commit: Nov 1, 2026
Audits on skills.sh: Gen Agent Trust Hub: pass, Socket: pass, Snyk: pass
What it includes: 6 files including SKILL.md: 4 reference files and an openai.yaml (no scripts)
Needs: The cmux macOS app and its cmux command line tool

What it includes

Shows the current window, workspace, pane and surface
Gives the caller context. Output uses short refs like workspace:2 unless you ask for UUIDs.
Runs code · cmux identify
cmux list-windows, list-workspaces, list-panes, list-pane-surfaces
Reads the layout so Claude can target the right pane.
Runs code · List windows, workspaces, panes, surfaces
cmux new-workspace, new-split, new-pane, new-surface
With --command, the new terminal runs the text in a live shell right away.
Runs code · Create workspaces and splits
move-surface, split-off, reorder-surface, reorder-workspace, move-workspace-to-window
Surface identity stays stable across moves. Layout commands do not take focus unless you pass --focus true.
Runs code · Move and reorder
focus-pane, focus-window, select-workspace, close-surface, close-workspace, close-window
The close commands remove windows, workspaces or surfaces.
Delete · Focus and close
cmux workspace-action: set-color, rename, pin, set-description and more
Runs the workspace right-click actions, such as color, rename, pin and mark read.
Runs code · Workspace actions
Flashes a surface or workspace for visual confirmation
Also surface-health checks for hidden or detached surfaces.
Runs code · trigger-flash
cmux docs settings, cmux settings, cmux reload-config
Settings live in ~/.config/cmux/cmux.json. The skill says to copy an existing file to a timestamped .bak before editing.
Runs code · Settings and reload
cmux browser --surface <surface> download list
Lists completed downloads for a browser surface. Full browser control is in the cmux-browser skill.
Runs code · Browser download history

From the official docs

Permissions

Medium risk

What it can do

Read your data
Create and change things
Delete things
Read-only mode

Watch out for

New panes can run any command
--command on new-split, new-pane, new-surface and new-workspace delivers the text plus Enter to a normal shell. Pipes, && and $VARS are interpreted by that shell. Check the text before you approve. github.com
It can close your windows and workspaces
The references list close-window, close-workspace and close-surface. github.com
It edits cmux settings
SKILL.md says cmux-owned settings live in ~/.config/cmux/cmux.json and tells Claude to copy an existing file to a timestamped .bak before editing. Terminal look-and-feel belongs in the Ghostty config instead. github.com

Security advisories

No published security advisories as of Nov 2, 2026.

Technical details

Turning on read-only	No read-only mode. Ask Claude to only list and identify.
Sign-in and keys	SKILL.md does not mention any account or key.
Scopes	Runs the cmux CLI against your open cmux app Can start commands in new terminal panes with --command Can close windows, workspaces and surfaces Can edit ~/.config/cmux/cmux.json

Questions

What does the cmux skill do?

It makes Claude control the cmux terminal app from the command line. Claude can list and create windows, workspaces, panes and surfaces, move and focus them, run a command in a new split, and flash a surface for confirmation.

What is cmux?

cmux is a Ghostty-based macOS terminal with vertical tabs and notifications for AI coding agents, per its README. The skill only works if cmux is installed and the cmux CLI is available.

How do I install it?

Use the install box at the top of this page. It installs the cmux app (DMG or Homebrew, per the README) and the skill. The skill does nothing without the cmux app.

Is this an official cmux skill?

It is in the cmux repo itself, owned by manaflow-ai, so it comes from the maker of cmux. The README also points to a separate cmux-skills collection.

Does it work on Windows or Linux?

Only macOS is documented. SKILL.md describes a "top-level macOS cmux window", and the README offers a macOS DMG and a Homebrew cask.

Do I need the other cmux skills?

No. SKILL.md links to cmux-workspace, cmux-settings, cmux-browser, cmux-markdown and cmux-capture for deeper topics, such as browser automation. They are optional.

Is it safe?

It bundles no scripts. It has Claude run cmux commands, and --command starts text in a new terminal shell, so Claude can start any command there. It can also close windows and edit your cmux settings file. Approve commands you do not recognise.

Information

updated Nov 2, 2026

Repository: manaflow-ai/cmux
Folder: skills/cmux

manaflow-ai/cmux skills.sh

Sources

Docs, issue trackers and discussions this page is built from.

Show all 6

cmux README · github.com
cmux SKILL.md · github.com
panes-surfaces.md · github.com
windows-workspaces.md · github.com
trigger-flash-and-health.md · github.com
handles-and-identify.md · github.com