cmux-skills

Give Claude Code full control of your cmux workspace — split panes, automate browsers, display docs, all from natural language.

cmux is a macOS terminal with split panes, embedded browsers, and a markdown viewer built in — designed for AI agents to control programmatically.

Claude Code doesn't know any of that. It just sees a shell. This plugin teaches it what cmux can do.

Install

/plugin marketplace add mangledmonkey/cmux-skills
/plugin install cmux

What Claude gains

• Split panes and arrange your workspace by asking
• Open a browser beside your terminal and debug web apps visually
• Display docs, plans, or notes in a live-updating markdown panel
• Capture debug window snapshots with a single command

Skills

cmux

Control windows, workspaces, panes, and surfaces — create, focus, move, reorder, identify.

You say: "Split my workspace and move the browser to the right pane"

Claude runs:

cmux new-split right --panel pane:1
cmux move-surface --surface surface:7 --pane pane:2 --focus true

browser

Automate cmux webview surfaces — open sites, snapshot interactive refs, fill forms, click, wait.

You say: "Open my dev server and check if the login form works"

Claude runs:

cmux browser open http://localhost:3000 --json
cmux browser surface:7 snapshot --interactive
cmux browser surface:7 fill e1 "[email protected]"
cmux browser surface:7 click e2 --snapshot-after

markdown

Open markdown files in a formatted panel with live file watching alongside the terminal.

You say: "Show my plan file in a side panel"

Claude runs:

cmux markdown open plan.md
# Panel auto-updates when the file changes on disk

debug-windows

Manage Sidebar, Background, and Menu Bar Extra debug windows. Capture combined snapshots.

You say: "Grab a snapshot of all debug windows"

Claude runs:

${CLAUDE_PLUGIN_ROOT}/skills/debug-windows/scripts/debug_windows_snapshot.sh --copy

Cross-skill orchestration

The real power is combining skills. Ask Claude to write a reusable script and it will wire them together.

You say: "Write a script that sets up a research workspace — takes a URL, opens it in a browser pane, and puts a notes file beside it"

Claude writes:

#!/usr/bin/env bash
set -euo pipefail

URL="${1:?usage: research.sh <url> [notes-file]}"
NOTES="${2:-research-notes.md}"

# Start the notes file if it doesn't exist
[ -f "$NOTES" ] || printf "# Research Notes\n\n## Source\n%s\n" "$URL" > "$NOTES"

# Open browser to the target URL
RESULT=$(cmux --json browser open "$URL")
SURFACE=$(echo "$RESULT" | jq -r '.surface_id')
cmux browser "$SURFACE" wait --load-state complete --timeout-ms 15000

# Open notes panel beside it
cmux markdown open "$NOTES"

# Flash the browser to confirm
cmux trigger-flash --surface "$SURFACE"

Three skills, fifteen lines, fully parameterized.

Requirements

• cmux (macOS 14.0+)
• Claude Code

Upstream sync

Skills are sourced from manaflow-ai/cmux and synced weekly via GitHub Actions. A Claude CLI step reviews each sync PR before merge to fix paths and references.

License

See the upstream cmux repository for license information.