What is capslkagent?

Capslkagent turns your keyboard's Caps Lock light, or on Mac laptops the keyboard backlight instead, into a simple status indicator for the Claude Code coding agent. The light is solid on while the agent is working, blinks when it needs your attention such as a permission prompt or notification, and turns off when the agent is idle. This means you can glance at your keyboard and know what your agent is doing without checking the terminal. It is written in Rust and ships as a single small binary with no runtime dependencies, and it works across macOS, Linux, and Windows. You can install it through Homebrew on macOS and Linux, or build it yourself from source with cargo. Once installed, a single command wires it into Claude Code's own hook system, so the light turns on when you submit a prompt, turns off when the agent stops or a session ends, and blinks when Claude Code sends a notification that it needs you. You can also drive the light manually from the command line, turning it on, off, or blinking at a chosen speed, and check its current status. Touching your keyboard or mouse while it is blinking counts as acknowledging the alert and turns the light off again, using the operating system's own idle detection so no extra permissions are needed on macOS and Windows. On Linux, blinking instead stops the next time the light is turned on or off. Each platform works differently under the hood: macOS talks directly to system frameworks to control the caps lock state or keyboard backlight, Linux writes to a system file that drives the LED without affecting typing, and Windows simulates an actual caps lock key press. Because of that, on macOS and Windows using the caps lock light also flips your real caps lock state, so anything you type elsewhere while the agent works will come out in capitals, a limitation the author notes plainly. The project is released under the MIT license.