cmux-settings

cmux-settings is a skill for Claude Code, Codex from DJRHails/dotfiles. It costs 124 tokens per session (1,471 once invoked), scanned B, a copy of cmux-settings, MIT.

A settings-management skill for cmux, a terminal application that can organize multiple command-line workspaces. It reads and edits cmux's JSONC settings file, which is JSON that may contain comments.

In plain words
What is it for?
Use it to change cmux appearance, sidebar, notifications, automation, browser, and keyboard-shortcut preferences, then validate or open the settings file.
Why use it?
It reduces the risk of editing settings by hand and validates setting names before saving changes.

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

Made for: Claude Code, 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.

agentmods badge for cmux-settings

README.md
[![agentmods](https://agentmods.dev/badge/skills/djrhails/dotfiles/cmux-settings.svg)](https://agentmods.dev/skills/djrhails/dotfiles/cmux-settings)
Your own site
<a href="https://agentmods.dev/skills/djrhails/dotfiles/cmux-settings"><img src="https://agentmods.dev/badge/skills/djrhails/dotfiles/cmux-settings.svg" alt="Measured on agentmods" height="20"></a>
Per session 124 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,471 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. Scan, not verified.
Origin 97% 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 $0.00124 $0.01471
Opus 5 $0.00062 $0.00736
Sonnet 5 $0.00025 $0.00294
Haiku 4.5 $0.00012 $0.00147

Measured 3d ago against content hash 510e78bcc080, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

cmux-settings scanned grade B with 1 finding 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.

Subtle steeringmediumPrompt injection

Instructions that bias recommendations or shape behaviour without the user noticing.

- Never tell the user to restart cmux to apply a change. The file watcher reloads on save.
Origin

This is a copy

97% identical to cmux-settings — 6 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-settings/SKILL.md · 84 lines

How it starts

The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.

cmux-settings

cmux reads user settings from ~/.config/cmux/cmux.json (JSONC). The app installs a file watcher; saving the file applies changes immediately, no restart needed. Legacy ~/.config/cmux/settings.json is read only as a fallback for keys not present in cmux.json.

Schema: https://raw.githubusercontent.com/manaflow-ai/cmux/main/web/data/cmux.schema.json. The authoritative path list lives in Sources/CmuxSettingsJSONPathSupport.swift in the cmux checkout, and the installed skill includes a generated copy in references/all-keys.md. Top-level sections are app, terminal, notifications, sidebar, sidebarAppearance, workspaceColors, automation, browser, and shortcuts. Non-settings sections (actions, ui, commands, vault, rightSidebar) coexist in the same file.

Helper script

Use the bundled helper for every read/write. It strips JSONC comments, writes atomically, and validates keys against the schema.

# From a cmux checkout
skills/cmux-settings/scripts/cmux-settings <subcommand>

# From the installed skill
~/.agents/skills/cmux-settings/scripts/cmux-settings <subcommand>

For brevity in the rest of this doc, assume the script is on $PATH as cmux-settings. To make it so for a session from a checkout: export PATH="$PWD/skills/cmux-settings/scripts:$PATH".

Subcommands:

Command What it does
cmux-settings path Print the config path.
cmux-settings dump Print the raw file (preserves comments).
cmux-settings dump --no-comments Print the parsed JSON.
cmux-settings get <a.b.c> Print value at dotted JSON path.
cmux-settings set <a.b.c> <value> Set value. <value> is parsed as JSON (true, 42, "text", […], {…}); plain strings without quotes are stored as strings.
cmux-settings unset <a.b.c> Delete key, reverting to the in-app default.
cmux-settings list-supported List every settings JSON path the app recognizes.
cmux-settings validate Parse the file and flag any unknown settings keys.
cmux-settings open Open cmux.json in $EDITOR, VS Code, Cursor, or TextEdit.

Read the full file on GitHub · 84 lines

Files

What ships with it

3 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.

  1. 3d ago First seen · 84 lines · 124 tokens per session scan B 510e78bcc080

Subscribe to this mod's changes

cmux-settings is a skill published in the GitHub repository DJRHails/dotfiles (2 stars, last pushed today), licensed MIT. It adds 124 tokens to every session and 1,471 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it B with 1 finding (subtle steering). It is 97% identical to cmux-settings, differing in 6 lines, and is treated as a copy.

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