What is cmux-customization?

A configuration guide for cmux, a terminal workspace application, covering its buttons, commands, layouts, shortcuts, and related settings.

Use it to customise workspace creation, tab-bar and Dock controls, command menus, keyboard shortcuts, notifications, browser routing, and layouts for worktrees, services, previews, or SSH sessions.

It helps tailor cmux to the way a person works without losing existing configuration. It also provides a way to validate configuration changes.

cmux-customization — Skill for Codex by disler

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 disler/learning-cmux-with-agents --skill cmux-customization

Clone the repo

git clone --depth 1 https://github.com/disler/learning-cmux-with-agents

Made for: 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/disler/learning-cmux-with-agents/cmux-customization/github.svg)](https://agentmods.dev/skills/disler/learning-cmux-with-agents/cmux-customization)

Your own site

<a href="https://agentmods.dev/skills/disler/learning-cmux-with-agents/cmux-customization"><img src="https://agentmods.dev/badge/skills/disler/learning-cmux-with-agents/cmux-customization/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/disler/learning-cmux-with-agents/cmux-customization"><img src="https://agentmods.dev/badge/skills/disler/learning-cmux-with-agents/cmux-customization.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,375 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector warn 7 Sept 2026

SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

medium Rogue Agent · line 16
Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.

Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.

How audits are shown

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	$0.00066	$0.02375
Opus 5	$0.00033	$0.01188
Sonnet 5	$0.00013	$0.00475
Haiku 4.5	$0.00007	$0.00237

Measured 9d ago against content hash 8ed1c3435d36, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, 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 9d 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

Copies of this mod

1 near-identical copy found in the catalogue:

cmux-customization — 98% identical, 2 lines differ

ai_docs/cmux-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

2 files 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.

9d ago First seen · 235 lines · 66 tokens per session scan A 8ed1c3435d36

Subscribe to this mod's changes

cmux-customization is a skill published in the GitHub repository disler/learning-cmux-with-agents (109 stars, last pushed 2mo ago), licensed MIT. It adds 66 tokens to every session and 2,375 once invoked, about $0.0003 per session on Opus 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 2026-08-30.

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cmux-customization