cmux-settings

name: cmux-settings description: "View and edit cmux settings in ~/.config/cmux/cmux.json. Use when the user wants to change cmux preferences (appearance, sidebar, notifications, automation, browser, shortcuts), set a value by JSON path, validate the file, open it in an editor, or look up which keys cmux recognizes. Triggers on '/cmux-settings', 'change cmux setting', 'set in cmux', 'cmux config', 'cmux.json', or 'rebind a cmux shortcut'."

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 an installed Codex skill
~/.codex/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.

--file <path> overrides the target file (useful for --file ~/.config/cmux/settings.json when the user keeps things in the legacy file).

Workflow

Confirm the change. If the user named a setting in plain English (e.g. "make the sidebar tint match the terminal background"), look it up first.
```
cmux-settings list-supported | rg -i 'sidebar.*terminal|terminal.*sidebar'
```

Set the value. JSON literals (true, false, numbers, arrays, objects) must be valid JSON. Plain words are stored as strings.

cmux-settings set sidebarAppearance.matchTerminalBackground true
cmux-settings set app.appearance dark
cmux-settings set shortcuts.bindings.toggleSidebar cmd+b
cmux-settings set shortcuts.bindings.newTab '["ctrl+b","c"]'
cmux-settings set browser.hostsToOpenInEmbeddedBrowser '["localhost","*.internal.example"]'

Verify by reading back and validating.

cmux-settings get sidebarAppearance.matchTerminalBackground
cmux-settings validate

Tell the user it auto-reloaded. No app restart. If they want to revert, run cmux-settings unset <key>.

Quick reference

Appearance: app.appearance = "system" | "light" | "dark", app.appIcon, app.menuBarOnly, app.minimalMode.
Sidebar tint: sidebarAppearance.matchTerminalBackground, sidebarAppearance.tintColor, sidebarAppearance.tintOpacity (0..1).
Sidebar details: sidebar.hideAllDetails, sidebar.showBranchDirectory, sidebar.showPullRequests, sidebar.showPorts, sidebar.showLog.
Notifications: notifications.dockBadge, notifications.sound (enum incl. "none", "custom_file"), notifications.customSoundFilePath, notifications.hooks (array).
Browser: browser.defaultSearchEngine, browser.theme, browser.openTerminalLinksInCmuxBrowser, browser.hostsToOpenInEmbeddedBrowser.
Automation: automation.socketControlMode (off | cmuxOnly | automation | password | allowAll), automation.portBase, automation.portRange.
Shortcuts: shortcuts.bindings.<actionId> = "cmd+b", ["ctrl+b","c"], null, or "" to unbind. See references/shortcut-actions.md.

For the full list of settings, defaults, and descriptions, run cmux-settings list-supported or read references/all-keys.md.

Rules

Only edit cmux.json. Never edit settings.json unless the user explicitly asks; it is legacy and only read when the key is absent from cmux.json.
Never tell the user to restart cmux to apply a change. The file watcher reloads on save.
Always validate after a bulk edit: cmux-settings validate. Unknown keys mean the user pasted a key the app does not consume.
Do not blindly overwrite top-level sections (actions, ui, commands, vault, rightSidebar). They live in the same file and contain non-settings config the user has hand-tuned.
Shortcut action ids must match the schema enum. Look them up in references/shortcut-actions.md before binding.
Color values must be #RRGGBB. Opacities are 0..1.
For settings the user expressed in app-level language (e.g. "Settings > Notifications > Dock badge"), translate to the matching JSON path first; the docs page at web/app/[locale]/docs/configuration/page.tsx mirrors the schema 1:1.