Building Audio Alerts with TTS for AI Coding Agents

Ever wish your AI coding agent could actually speak to you? I've been working on adding audio alerts with text-to-speech to Gemini CLI, and here's how it works.

The Problem

When running AI coding agents in the background, you often miss important moments:

• When the agent needs your permission to run a tool
• When an error occurs
• When a long task completes

You either have to constantly check the terminal or miss important updates entirely.

The Solution: Audio Alerts + TTS

I built a hook system that plays themed sounds followed by spoken messages:

Sounds

Each theme has its own sound:

• retro - 8-bit game sounds
• espionage - High-tech clicks
• hero - Dramatic fanfare
• portal - Magical transitions
• premium - Elegant chimes

Spoken Messages

After each sound, a TTS message plays:

Event	Retro Theme	Espionage Theme
Permission needed	"Permission needed"	"Agent requesting permission"
Error	"Error detected"	"Critical failure detected"
Done	"Game over. You win"	"Mission accomplished"

Cross-Platform Support

The implementation works on:

• macOS: Uses built-in say command and afplay
• Linux: Supports espeak, gtts-cli, and play
• Windows: Uses PowerShell's System.Speech and SoundPlayer

How It Works

The hook intercepts Gemini CLI events:

# Play sound
play_audio "$ASSETS_DIR/done.wav"

# Wait a bit
sleep 0.3

# Speak the message
speak "Task complete"

All runs non-blocking, so the agent keeps working while you get audio feedback.

Installation

Clone the repo:

git clone https://github.com/HainanZhao/gemini-extension-audio-alerts
cd gemini-extension-audio-alerts

Set your theme:

export AUDIO_ALERTS_THEME=retro

What's Next

Possible enhancements:

• Custom voice selection
• More themes
• Sound mixing
• Volume control

The code is open source and available at: https://github.com/HainanZhao/gemini-extension-audio-alerts

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This post was written with assistance from AI coding agents.