Command Input

日本語

Command Input is a lightweight macOS menu bar app that switches Japanese input modes with single taps of the Command keys:

• Left Command (tap alone) → Eisu (英数 / Alphanumeric)
• Right Command (tap alone) → Kana (かな / Japanese)

Standard keyboard shortcuts such as Command-C or Command-Space pass through unchanged.

Requirements

• Platform: macOS 14.0 Sonoma or later
• Architecture: Apple silicon and Intel (Universal release builds)
• Build (source only): Swift 6 and Xcode Command Line Tools

Installation

Homebrew (recommended)

Command Input is available via a Homebrew tap. Homebrew 7 requires trusting the cask before installation:

brew trust --cask gajeroll/tap/command-input
brew install --cask gajeroll/tap/command-input

If you previously installed Command Input manually, delete /Applications/Command Input.app before running the cask install. Homebrew will refuse to overwrite an existing application.

On first launch from /Applications, the app enables Launch at Login automatically.

Prebuilt binary

Download the latest CommandInput-<version>.zip from Releases, unzip it, and drag Command Input.app to /Applications.

Build from source

git clone https://github.com/gajeroll/command-input.git
cd command-input
make            # Build build/Command Input.app (host architecture)
make run        # Run from the build directory
make install    # Copy to /Applications

Command Input runs as a menu bar accessory and does not appear in the Dock.

Upgrades

There is no in-app updater. If installed via Homebrew:

brew upgrade --cask

If installed manually, replace /Applications/Command Input.app with the newer release.

Uninstallation

Turn the in-app Launch at Login toggle off before uninstalling if you do not want a leftover Login Items record.

• Homebrew:

  brew uninstall --cask --zap command-input

  --zap removes the application and its preferences plist. macOS Login Items (BTM) registrations and Accessibility (TCC) grants are not cleared by Homebrew.
• Source / manual:

  make uninstall  # Remove /Applications/Command Input.app

  You can also quit the app and move /Applications/Command Input.app to the Trash.

Permissions and Privacy

Command Input requires Accessibility permission to observe modifier keys and post input-switching events.

• Granting permission: Enable the app under System Settings > Privacy & Security > Accessibility when prompted.
• Input Monitoring is not required. The app uses a session-level CGEventTap and does not need the broader Input Monitoring permission.
• What the tap does: The tap is created with listenOnly, so it cannot modify or suppress events. It observes keyDown, keyUp, and flagsChanged events so shortcuts such as Command-A or held keys cancel a pending switch. Keystrokes are never stored or sent anywhere.
• Privacy manifest: PrivacyInfo.xcprivacy is bundled into the app (no tracking, no collected data, and UserDefaults reason CA92.1).

See SECURITY.md for the full policy and a verification command.

Launch at Login

Command Input manages startup through macOS SMAppService and an internal preference. The stored preference is the source of truth, so a registration that macOS silently drops is restored instead of being treated as an opt-out.

Default behavior

• Installed app (/Applications or ~/Applications): enabled automatically on first launch.
• Development builds (build/): automatic registration is off so a temporary path is not recorded. The menu toggle still works.

Approval, repair, and opt-out

• Approval required: If macOS asks for approval, choose Open Login Items Settings in the app menu and enable Command Input once.
• Repair: If macOS loses the registration, the app retries a few times and then shows Repair Launch at Login in the menu.
• Disabling: Use the in-app toggle. Removing the item in System Settings only clears the system record, so the app restores it from the stored preference.

Troubleshooting

• Keys are not switching: Open System Settings > Privacy & Security > Accessibility and confirm Command Input is enabled. After an update or identity change, turn the checkbox off and on again.
• Menu shows "Repair Launch at Login": Click the item to re-register with macOS.
• Menu shows "Approve Command Input in Login Items": Open Login Items in System Settings and enable the app.

Development

Contributions are welcome. See CONTRIBUTING.md for local setup, code signing, architecture notes, and the release workflow.

make            # Build local host binary
make test       # Run test suite via Swift Testing
make run        # Build and run locally
make clean      # Remove build artifacts

Security

For event-tap guarantees and vulnerability reporting, see SECURITY.md.

Roadmap

• DMG packaging
• Automatic updates

Credits

Inspired by iMasanari/cmd-eikana and dominion525/cmd-eikana.

License

Distributed under the MIT License.