[FEATURE] System notifications/sound alerts when Claude needs user input or completes tasks

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When working on long-running tasks with Claude Code, users often step away from their terminal. Currently, there's no way to know when Claude has finished processing or needs user permission without actively monitoring the terminal window. This creates inefficiency - users either:

• Waste time frequently checking if Claude is done
• Miss prompts for user input, causing delays
• Context-switch inefficiently between tasks

Proposed Solution

Add system notifications and/or audio alerts that trigger when:

• Claude completes a task and is waiting for the next command
• Claude requires user permission to proceed (e.g., tool confirmation)
• Claude encounters an error that needs attention

Implementation could include:

• Ubuntu: Use notify-send for desktop notifications
• macOS: Use native notification system
• Cross-platform: Optional sound alert (beep or configurable audio file)
• Configuration option in .claude.json to enable/disable and customize behavior

Alternative Solutions

_No response_

Priority

High - Significant impact on productivity

Feature Category

Interactive mode (TUI)

Use Case Example

1. Developer runs: claude "refactor this codebase to use TypeScript"
2. Developer switches to browser to read documentation
3. Claude finishes after 10 minutes → notification pops up
4. Developer returns immediately instead of checking every 2 minutes

Additional Context

I'm willing to implement this if the maintainers are interested. Would appreciate guidance on preferred notification approach and config structure.