cmux-customization

cmux-customization is a skill for Claude Code, Codex from DJRHails/dotfiles. It costs 80 tokens per session (2,389 once invoked), scanned A, a copy of cmux-customization, MIT.

A configuration guide for cmux, a terminal application for organizing workspaces, browser views, and development sessions. It covers actions, layouts, buttons, shortcuts, and related settings.

In plain words
What is it for?
Use it to customize workspace layouts, terminal and browser controls, command menus, notifications, shortcuts, sidebar behavior, and development workflows.
Why use it?
It helps you change cmux behavior without losing existing configuration or relying on undocumented settings.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/djrhails/dotfiles/cmux-customization
Any agent
npx skills add DJRHails/dotfiles --skill cmux-customization
Clone the repo
git clone --depth 1 https://github.com/DJRHails/dotfiles

Made for: Claude Code, Codex.

Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,389 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 98% copy Near-identical to another mod 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.

ModelPer sessionOnce invoked
Fable 5 $0.00080 $0.02389
Opus 5 $0.00040 $0.01195
Sonnet 5 $0.00016 $0.00478
Haiku 4.5 $0.00008 $0.00239

Measured 3d ago against content hash 04a2df61b54b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cmux-customization 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 3d 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.

Origin

This is a copy

98% identical to cmux-customization — 2 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

modules/agents/skills/cmux-customization/SKILL.md · 235 lines

How it starts

The opening of the file, as written. The whole thing — 235 lines — stays where its author put it; the contents beside it link to each section on GitHub.

cmux Customization

Use this skill for user-facing cmux customization. Keep the user's config intact, prefer schema-backed edits, and validate before reporting completion.

What Can Be Customized

  • Custom actions: define reusable actions in cmux.json. Actions can appear in Cmd+Shift+P, surface tab bars, shortcuts, and the plus-button right-click menu.
  • New workspace button: set ui.newWorkspace.action to replace the normal plus-button click, and ui.newWorkspace.contextMenu to control right-click actions. ui.newWorkspace.rightClick is accepted as an alias, but new examples should use contextMenu.
  • Surface tab bar buttons: set ui.surfaceTabBar.buttons to replace the default tab bar buttons. Include built-in IDs such as cmux.newTerminal, cmux.newBrowser, cmux.splitRight, and cmux.splitDown only when they should stay visible.
  • Workflows and layouts: use commands with workspace definitions to open a worktree, multiple checkouts, local services, browser previews, or SSH sessions in a deliberate split layout.
  • Dock controls: create .cmux/dock.json or ~/.config/cmux/dock.json for right-sidebar terminal controls such as logs, test watchers, git TUIs, dev servers, queues, or cmux feed tui --opentui.
  • Sidebar and app behavior: use cmux-settings for supported settings such as appearance, sidebar display, notification behavior, browser routing, automation, shortcuts, and new-workspace placement.
  • Workspace metadata: use the cmux CLI or cmux-workspace for workspace names, descriptions, colors, read state, and sidebar metadata updates.
  • Feed and notifications: use cmux hooks setup for Feed event sources, notification settings for delivery behavior, and notification hooks in cmux.json for filtering or post-processing banners.
  • Team presets and examples: use project-local .cmux/cmux.json and .cmux/dock.json to share worktree, SSH, review, dev, CI, and docs workspace patterns with a repo.
  • Import, export, and reset: back up the current config, apply the smallest diff, validate it, and keep a rollback path for user-owned customizations.
  • Terminal behavior: use Ghostty config for fonts, themes, cursor style, copy-on-select, shell integration, terminal keybindings, and terminal rendering.

Read the full file on GitHub · 235 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.

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.

  1. 3d ago First seen · 235 lines · 80 tokens per session scan A 04a2df61b54b

Subscribe to this mod's changes

cmux-customization is a skill published in the GitHub repository DJRHails/dotfiles (2 stars, last pushed 8d ago), licensed MIT. It adds 80 tokens to every session and 2,389 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 98% identical to cmux-customization, differing in 2 lines, and is treated as a copy.

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