diff --git a/README.md b/README.md
index ac54a51..9ff291e 100644
--- a/README.md
+++ b/README.md
@@ -31,3 +31,37 @@ git config --global user.email "$GIT_AUTHOR_EMAIL"
 
 Run `./boostrap.sh`, this will create all the necessary symlinks, then source
 `.zshrc`. This is a **destructive** process, so backup your dotfiles first.
+
+## Auto switch between light and dark mode
+
+To switch between dark and light mode automatically, we use a helper lib.
+
+Clone it from `https://github.com/bouk/dark-mode-notify` then run `make` and `make install`.
+
+Then make a script to run is automatically, put the plist where your system can find it: `~/Library/LaunchAgents/ke.bou.dark-mode-notify.plist` with the following content:
+
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
+"http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+    <key>Label</key>
+    <string>ke.bou.dark-mode-notify</string>
+    <key>KeepAlive</key>
+    <true/>
+    <key>StandardErrorPath</key>
+    <string>/Users/jonny/.local/var/log/dark-mode-notify-stderr.log</string>
+    <key>StandardOutPath</key>
+    <string>/Users/jonny/.local/var/log/dark-mode-notify-stdout.log</string>
+    <key>ProgramArguments</key>
+    <array>
+       <string>/usr/local/bin/dark-mode-notify</string>
+       <string>/Users/jonny/git/dotfiles/zsh/dark-mode-notify.zsh</string>
+    </array>
+</dict>
+</plist>
+```
+
+Make the log file and script file point to the right location. For clarity `dark-mode-notify.zsh` is in this repo.
+