What is cmux-claude-skill CLAUDE.md?

A set of Claude Code instructions for using cmux, a macOS terminal designed for AI-assisted work, instead of tmux. It also describes when to fall back to tmux.

Use it for terminal multiplexing on macOS, including managing workspaces, panes, terminal tabs, and browser tabs; use tmux in SSH, CI, or remote environments.

It helps Claude Code use the correct terminal controls and environment settings when working inside cmux.

How goddaehee/cmux-claude-skill configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to goddaehee/cmux-claude-skill. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/goddaehee/cmux-claude-skill/main/CLAUDE.md

Clone the repo

git clone --depth 1 https://github.com/goddaehee/cmux-claude-skill

Made for: Claude Code.

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/instructions/goddaehee/cmux-claude-skill/claude-md/github.svg)](https://agentmods.dev/instructions/goddaehee/cmux-claude-skill/claude-md)

Your own site

<a href="https://agentmods.dev/instructions/goddaehee/cmux-claude-skill/claude-md"><img src="https://agentmods.dev/badge/instructions/goddaehee/cmux-claude-skill/claude-md/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/instructions/goddaehee/cmux-claude-skill/claude-md"><img src="https://agentmods.dev/badge/instructions/goddaehee/cmux-claude-skill/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 112 This file is loaded in full into every session.

When invoked 112 The same file — it is already loaded in full.

Security scan A 0 findings. 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	$0.00112	$0.00112
Opus 5.5	$0.00045	$0.00045
Sonnet 5.5	$0.00022	$0.00022
Haiku 4.5	$0.00011	$0.00011

Measured 2mo ago against content hash d247f16a811b, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

cmux-claude-skill CLAUDE.md scanned grade A with 0 findings 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 2mo 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 10 lines

What it actually says

cmux-claude-skill

This plugin teaches AI agents to use cmux (AI-native macOS terminal) instead of tmux.

Key Points

Use cmux CLI commands, not tmux, for terminal multiplexing on macOS.
Environment variables CMUX_WORKSPACE_ID, CMUX_SURFACE_ID are auto-set in cmux terminals.
For full CLI reference, invoke /cmux skill.
Fall back to tmux in SSH/CI/remote environments where cmux is unavailable.

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.

2mo ago First seen · 10 lines · 112 tokens per session scan A d247f16a811b

Subscribe to this mod's changes

cmux-claude-skill CLAUDE.md is an instructions file published in the GitHub repository goddaehee/cmux-claude-skill (2 stars, last pushed 6mo ago), licensed MIT. It adds 112 tokens to every session, about $0.0004 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

cmux-claude-skill CLAUDE.md next to 6 instructions from other repositories
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cmux-claude-skill: Instructions file for Claude Code