Task banner skill

task-banner

Show a large, always-on-top desktop banner when Claude Code finishes a turn — with a one-line summary of what was actually completed. Works even when macOS Notification Center silently drops osascript display notification calls (a common problem: the CLI has no Notification Center registration, so the command exits 0 but nothing shows).

The banner is a borderless Cocoa overlay window drawn by mac-overlay.js (a JXA script adapted from peon-ping), so no notification permissions are needed.

Requirements

• macOS (the overlay uses Cocoa via JXA / osascript -l JavaScript)
• Claude Code with hooks support

Setup

1. Copy mac-overlay.js from this skill directory to ~/.claude/scripts/mac-overlay.js.

2. Merge a Stop hook into ~/.claude/settings.json (read the file first and preserve existing hooks):

{
  "hooks": {
    "Stop": [
      {
        "matcher": "",
        "hooks": [
          {
            "type": "command",
            "command": "m=$(cat /tmp/claude-banner-msg 2>/dev/null); rm -f /tmp/claude-banner-msg; [ -f ~/.claude/banner.off ] || osascript -l JavaScript ~/.claude/scripts/mac-overlay.js \"${m:-Task done}\" blue \"\" 0 4 2>/dev/null || true",
            "async": true
          }
        ]
      }
    ]
  }
}

3. To make the banner show what was finished (instead of the generic "Task done"), add this to your global agent instructions file (~/.claude/CLAUDE.md or AGENTS.md):

After finishing each task, write a short summary of what was completed to /tmp/claude-banner-msg (e.g. printf 'Typecheck fixed and committed' > /tmp/claude-banner-msg). Identify the actual task; never use a generic "task done".

The Stop hook displays the message and deletes the file. If the file is absent, it falls back to "Task done".

Toggle (mute / unmute)

The hook checks a sentinel file — no config editing needed:

touch ~/.claude/banner.off   # mute the banner
rm -f ~/.claude/banner.off   # unmute

When the user asks to mute/unmute the banner, run the matching command and report the resulting state.

How it works / notes

• mac-overlay.js <message> <color> <icon> <slot> <dismiss_seconds> — color is blue/yellow/red, dismiss 0 means persistent-until-click.
• The hook consumes /tmp/claude-banner-msg even while muted, so no stale summary pops up later when unmuted.
• On recent macOS the JXA bridge constant NSTextAlignmentCenter evaluates to the legacy AppKit value (2), which the unified runtime treats as right-aligned — the bundled script hardcodes alignment 1 (center) to compensate.
• /tmp/claude-banner-msg is shared across parallel Claude sessions; if two finish in the same instant one banner may show the other's summary. Use a per-session file path if that ever matters.