attn LED 1.0 (macOS)

Version 1.0 landed with a single aim: turn the MacBook camera LED into a notification light you can actually see when your machine is on mute and banners are off. It monitors the macOS notifications database via FSEvents, so it catches alerts from apps that normally sit quiet during a Focus session. No sound, no pop-ups — just a blink from the green light next to the camera.

People tend to ask three things before they install it. First, whether it clashes with FaceTime or Zoom. It pauses blinking during active camera use, so a video call doesn't become a disco. Second, whether it spams you with every system ping. The app can limit LED notifications to a short list of apps — Slack, Mail, Messages, Discord, Teams, Telegram — and ignore the rest. Third, whether it works on older hardware. It runs on Apple Silicon and Intel Macs from macOS 12 upwards.

New apps get picked up automatically after you authorise the permissions. Once that's done, the LED becomes a physical nudge for messages you'd otherwise miss while deep in work. No interface to babysit, just a tick list of apps and the light doing its job.

Working session with attn LED

After a week with the app, the pattern settles. Start the day by launching attn LED from Launchpad. The dock icon sits there, doing nothing visible. I open Slack, Mail and Messages — the apps I want the light to watch.

Open the attn LED preferences panel. Tick the three apps. Close the panel. That is the setup done for the day. The app remembers the list between restarts, so next morning I only need to open it again.

The first alert came about ten minutes into a writing session. A green blink from the camera LED caught the corner of my eye. I ignored it, assuming it was a calendar reminder or a server alert. The light kept blinking every few seconds. After five minutes I gave in, switched to Slack, and found a colleague had DM'd me an urgent question. The light stopped as soon as Slack became the active window.

Later that afternoon I was on a FaceTime call. The app paused its blinking automatically, as promised. The caller never saw a strobing light next to my face. After the call ended, the blinking resumed for any messages that had arrived during the conversation.

The mental shift was subtle. I stopped glancing at notification badges and the menu bar. The LED told me, from across the room, whether anything needed my attention. Green light means "check when convenient". No light means "keep working".

Start with just two monitored apps to avoid alert overload

• Start with only two or three apps in the monitored list. Adding everything at once produces too many alerts and you learn to ignore the light.
• Place the MacBook so the camera LED is visible from your typical seating position. On an iMac or a closed-lid setup, the light may be hidden. A small mirror or a repositioned monitor can help.
• Expect a few false positives on day one. Some system notifications that macOS treats as important will trigger the LED until you either add the sending app to the monitored list or exclude it. The app's preferences list shows recent notification sources — use that to refine your filter.
• Keep the app running in the background during Focus sessions. The whole point is that it works while every other notification channel is silenced.

Workflow: filter a Slack channel for the LED

1. Open attn LED preferences and ensure Slack is ticked in the app list.
2. In Slack, mute all channels except the one you want to trigger the LED. Set Slack's own notification preferences to "Only highlight words and phrases" or "None".
3. Let attn LED monitor Slack's native notification database. When a message arrives in the unmuted channel, macOS sends a notification to the system database. attn LED picks it up via FSEvents and blinks the camera LED.
4. When you see the blink, switch to Slack. The LED stops as soon as Slack becomes the active app. Read and reply, then switch back to your main work.
5. If you need to exclude Slack entirely for a while, untick it in attn LED preferences. The app stays running but ignores Slack notifications until you re-enable it.

• macOS 12 or later
• Apple Silicon or Intel Mac with a camera LED