Here's the exact brief to reproduce it on another Mac.

1. Prerequisites

brew install terminal-notifier jq
which terminal-notifier   # confirm the path

/opt/homebrew/bin/terminal-notifier is the Apple Silicon path. On an Intel Mac it's /usr/local/bin/terminal-notifier — substitute whatever which prints into both commands below.

2. Add the hooks

Open ~/.claude/settings.json (create it if missing) and merge in this hooks block:

{
  "hooks": {
    "Notification": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "m=$(jq -r '.message // \"Claude needs your attention\"'); /opt/homebrew/bin/terminal-notifier -title \"Claude Code\" -message \"$m\" -sound Ping -group claude-code -activate com.microsoft.VSCode 2>/dev/null || true"
          }
        ]
      }
    ],
    "Stop": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "in=$(cat); t=$(printf '%s' \"$in\" | jq -r '.transcript_path // empty'); m=\"Done — ready for you\"; if [ -n \"$t\" ] && [ -f \"$t\" ]; then s=$(jq -rs '[.[] | select(.type==\"assistant\") | .message.content[]? | select(.type==\"text\") | .text] | last // empty' \"$t\" 2>/dev/null | tr '\\n' ' ' | sed 's/  */ /g' | cut -c1-140); [ -n \"$s\" ] && m=\"$s\"; fi; /opt/homebrew/bin/terminal-notifier -title \"Claude Code\" -message \"$m\" -sound Glass -group claude-code -activate com.microsoft.VSCode 2>/dev/null || true"
          }
        ]
      }
    ]
  }
}

If the file already has other keys (env, permissions, theme…), add "hooks" alongside them — don't replace the file.

3. Grant notification permission

terminal-notifier -title "Claude Code" -message "test"

macOS will prompt once. Then System Settings → Notifications → terminal-notifier → Allow, and set the style to Alerts if you want them to stay on screen.

4. Reload

Restart Claude Code (hooks are read at session start). Verify with /hooks — both Stop and Notification should be listed.

Tweakables