What is capsblink?

CapsBlink is a pair of small Mac apps that use an unusual trick: blinking the Caps Lock light on your keyboard as a notification, without changing the actual Caps Lock setting. Neither app needs extra hardware and both run entirely on your own computer, with no cloud accounts or tracking involved. The first app, called CapsBlink, watches any webpage you give it a link to, such as a live sports score page, and blinks the light when the page changes in a way that matches instructions you type in plain English, like blink when the game score changes. The second app, CapsBlink Agents, instead watches local AI coding assistants such as Claude Code or Codex, and blinks the light when one of them finishes a task and is waiting for you. To decide when to blink, CapsBlink fetches the watched page every so often, strips it down to plain text, and checks whether the text actually changed in a meaningful way. Only when something meaningfully differs does it hand the text to a small AI language model that runs locally on the Mac, which then decides whether that change matches what you asked it to watch for. The keyboard's Caps Lock light is then blinked briefly and returned to its normal state. Both apps are installed as regular Mac applications downloaded from the project's releases page, and since they are not signed by an official Apple developer account, the first launch requires a small extra step to open them. The apps also need permission to monitor keyboard input, which is how they are able to control the light. Anyone comfortable with a Mac's command line tools can instead build the apps from source, and the project provides a reusable core library that other developers could build their own tools on top of. The project is released under the MIT license, and the small AI model it bundles uses the Apache 2.0 license.