A control skill for cmux, a macOS terminal app that can run several coding agents in separate workspaces and panels. It can work with terminal and browser panels through commands or a local socket.

Use it to create and inspect workspaces, panes, and surfaces; automate browser panels; send notifications; manage sidebar details; and restore sessions.

It removes the need to manage terminal layouts and browser panels manually during multi-agent work. It also helps automation address the correct workspace instead of whichever one is currently visible.

cmux — Skill for Claude Code and Codex by pawel-cell

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add pawel-cell/cmux-ai-agents-bundle --skill cmux-skill

Clone the repo

git clone --depth 1 https://github.com/pawel-cell/cmux-ai-agents-bundle

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/pawel-cell/cmux-ai-agents-bundle/cmux-skill/github.svg)](https://agentmods.dev/skills/pawel-cell/cmux-ai-agents-bundle/cmux-skill)

Your own site

<a href="https://agentmods.dev/skills/pawel-cell/cmux-ai-agents-bundle/cmux-skill"><img src="https://agentmods.dev/badge/skills/pawel-cell/cmux-ai-agents-bundle/cmux-skill/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/pawel-cell/cmux-ai-agents-bundle/cmux-skill"><img src="https://agentmods.dev/badge/skills/pawel-cell/cmux-ai-agents-bundle/cmux-skill.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 86 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,338 The whole file, excluding the scripts and references it only reads on demand.

Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00086	$0.02338
Opus 5	$0.00043	$0.01169
Sonnet 5	$0.00017	$0.00468
Haiku 4.5	$0.00009	$0.00234

Measured 12d ago against content hash 7842849ce0b3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade B, and why

cmux scanned grade B with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

sudo ln -sf /Applications/cmux.app/Contents/Resources/bin/cmux /usr/local/bin/cmux

cmux-skill/SKILL.md · 174 lines

How it starts

The opening of the file, as written. The whole thing — 174 lines — stays where its author put it; the contents beside it link to each section on GitHub.

cmux Control

cmux is a native macOS terminal app for running multiple AI coding agents in parallel. It exposes a CLI (cmux) and a Unix-socket JSON-RPC API (/tmp/cmux.sock) for full topology and browser control.

Core Concepts

Window — top-level macOS cmux window
Workspace — sidebar tab within a window (one git branch / project context)
Pane — split region inside a workspace
Surface — tab inside a pane (terminal or browser)

Handles default to short refs (workspace:2, pane:1, surface:7); UUIDs accepted as input. Add --id-format uuids|both for full IDs in output.

Detect cmux in a Shell

[ -S "${CMUX_SOCKET_PATH:-/tmp/cmux.sock}" ] || exit 0   # bail if not in cmux
[ -n "${CMUX_WORKSPACE_ID:-}" ] && echo "inside cmux surface"

Injected env vars in every cmux-spawned terminal: CMUX_WORKSPACE_ID, CMUX_SURFACE_ID, CMUX_SOCKET_PATH, CMUX_PORT. Always anchor automation to CMUX_WORKSPACE_ID — the visually focused workspace may not be the agent's caller workspace.

Fast Start — Topology

cmux identify --json                              # who am I (window/workspace/pane/surface)
cmux tree                                         # full hierarchy
cmux list-workspaces --json
cmux list-panes --workspace "$CMUX_WORKSPACE_ID"
cmux list-surfaces --workspace "$CMUX_WORKSPACE_ID"

cmux new-workspace --name "feature-x" --cwd /path/to/repo
cmux new-pane --workspace "$CMUX_WORKSPACE_ID" --type terminal --direction right --focus false
cmux new-pane --workspace "$CMUX_WORKSPACE_ID" --type browser  --direction right --url http://localhost:3000
cmux move-surface --surface surface:7 --pane pane:2 --focus false
cmux split-off --surface surface:7 right
cmux reorder-surface --surface surface:7 --before surface:3
cmux close-surface --surface surface:7

Send Input

cmux send "echo hi\n"                                       # focused terminal
cmux send-key "ctrl+c"                                       # enter|tab|esc|backspace|arrows|ctrl+x|shift+tab
cmux send-surface --surface surface:7 "npm run build\n"      # specific surface
cmux send-key-surface --surface surface:7 enter

Read the full file on GitHub · 174 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

README.md 1.6 KB

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

12d ago First seen · 174 lines · 86 tokens per session scan B 7842849ce0b3

Subscribe to this mod's changes

cmux is a skill published in the GitHub repository pawel-cell/cmux-ai-agents-bundle (41 stars, last pushed 3mo ago), licensed MIT. It adds 86 tokens to every session and 2,338 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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