# cmux-terminal-multiplexer

Equips AI agents with CLI commands for terminal split orchestration and headless Chromium browser actions via surface handles.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 1400 installs · ★ 88
- Author: reason-machines
- License: not stated · policy=link-only · description only; the file stays with the author
- Source: https://github.com/reason-machines/trending-skills/tree/HEAD/skills/cmux-terminal-multiplexer/SKILL.md
- Updated: 2026-10-09
- HTML: https://affpapa.org/en/nevibecode/skills/cmux-terminal-multiplexer

## What it does

This skill teaches coding agents to manage workspaces through `cmux`. The agent spins up horizontal or vertical panes using `new-split right` or `new-split down`, sends commands to designated targets like `surface:22`, and captures output with `capture-pane`. Targeting runs directly against explicit surface handles. That structure prevents unexpected window focus shifts while background jobs run.

A headless Chromium runtime comes embedded inside `cmux`, so configuring an external Chrome installation is unnecessary. Web actions rely on interactive snapshot identifiers such as `e1` or `e2` instead of standard CSS selectors. Because DOM updates invalidate these handles immediately, the agent must generate a fresh snapshot after clicks or navigation steps.

## Requirements
- Works with: Playwright

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add reason-machines/trending-skills --skill cmux-terminal-multiplexer -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/cmux-terminal-multiplexer/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/cmux-terminal-multiplexer/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add reason-machines/trending-skills --skill cmux-terminal-multiplexer -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/cmux-terminal-multiplexer/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add reason-machines/trending-skills --skill cmux-terminal-multiplexer -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/cmux-terminal-multiplexer/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install reason-machines/trending-skills cmux-terminal-multiplexer
```

2. **Manually: put the files in place**
- File: `.github/skills/cmux-terminal-multiplexer/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add reason-machines/trending-skills --skill cmux-terminal-multiplexer -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/reason-machines/trending-skills --path skills/cmux-terminal-multiplexer
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/cmux-terminal-multiplexer/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add reason-machines/trending-skills --skill cmux-terminal-multiplexer -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/reason-machines/trending-skills/tree/HEAD/skills/cmux-terminal-multiplexer/SKILL.md

## When to use it
- Manage terminal splits side by side for concurrent command runs
- Run headless browser workflows without setting up an external Chrome
- Read terminal output and scrollback history by surface reference
- Execute browser actions using generated snapshot element references

## Example prompts
- Open a right terminal split with cmux and run npm test
- Navigate to https://example.com using cmux browser and take an interactive snapshot
- Read the latest output from surface:12 with cmux capture-pane

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From the same set: [reason-machines/trending-skills](https://affpapa.org/en/nevibecode/by/reason-machines/trending-skills.md) — 186 cards

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md