Google Chirp 3 HD TTS Skill

High-definition generative speech synthesis using Google Cloud Chirp 3 HD voices. Delivers superior realism, emotional expressiveness, and natural pacing using LLM-based generative audio models. Use when: (1) User requests audio/voice output with "tts" or "speak" triggers. (2) Content requires natural human-like prosody.

Overview

Generate ultra-realistic, human-like speech using Google's latest Chirp 3 HD generative models. This skill handles its own dependencies locally to remain portable.

Security Note: On first execution, this skill will run npm install locally within its own folder to fetch the official @google-cloud/text-to-speech library from the public npm registry.

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Trigger Detection

Recognize keywords like "tts", "speak", "voice", or "read this out loud" as TTS requests.

• Action: Extract the target text, strip the trigger keyword, apply "Natural Speech" formatting (see below), then call the tool using the auto-run logic below.

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Auto-Run Logic (Agent Instructions)

Follow these steps every time TTS is needed. Never assume gtts is in PATH — always run via node directly.

Step 1 — Find the skill folder

gtts.js lives in the same folder as this SKILL.md. Resolve that path:

SKILL_DIR="$(cd "$(dirname "$0")" && pwd)"

Step 2 — Check Node.js (Version 18+ Required)

if ! command -v node &>/dev/null; then
    echo "ERROR: Node.js is not installed."
    exit 1
fi

NODE_MAJOR=$(node -v | cut -d'v' -f2 | cut -d'.' -f1)
if [ "$NODE_MAJOR" -lt 18 ]; then
    echo "ERROR: Node.js 18 or higher is required for Google Chirp 3 HD."
    exit 1
fi

Step 3 — Auto-install dependency if missing

This installs the package locally inside the skill folder only.

if [ ! -d "$SKILL_DIR/node_modules/@google-cloud/text-to-speech" ]; then
    npm install @google-cloud/text-to-speech --prefix "$SKILL_DIR" --silent
fi

Step 4 — Run the script

node "$SKILL_DIR/gtts.js" --text "$TEXT" --voice "$VOICE" --out "$OUTFILE"

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Command Arguments

Argument	Description	Default
--text	Text to synthesize. Supports [pause] tags.	(required)
--voice	Voice short-name (e.g. Aoede, Charon, Puck)	Aoede
--out	Output filename (saved to $OPENCLAW_WORKSPACE)	output.mp3

Returns SUCCESS:/absolute/path/to/file.mp3 on success, or ERROR: ... on failure.

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Voice Selection

Gender	Recommended HD Voices
Female	Achernar (Default), Aoede, Leda, Kore, Zephyr, Despina, Gacrux, Vindemiatrix
Male	Charon, Puck, Fenrir, Orus, Achird, Algenib, Enceladus

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Prompt Engineering for Natural Speech

1. Pause Tags

Converted automatically into SSML <break> tags:

Tag	Duration
[pause short]	300ms
[pause]	600ms
[pause long]	900ms

2. Human-Like Formatting

• Contractions: Use "I'm", "don't", "can't" for a conversational tone.
• Ellipses: Use ... for trailing hesitation.
• Fillers: Use "Well,", "Um,", or "So," to mimic natural thought.

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Authentication

Uses Google Application Default Credentials (ADC). One-time setup:

gcloud auth application-default login

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Requirements

Requirement	Status
Node.js 18+	❌ Must be installed on system
OPENCLAW_WORKSPACE	ℹ️ Optional (Defaults to current dir)
@google-cloud/text-to-speech	✅ Auto-installed locally in skill folder
Google Cloud SDK + ADC login	❌ One-time manual step required

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Workflow

1. Detect Intent — Identify a TTS trigger keyword.
2. Format Text — Apply contractions, ellipses, and [pause] tags.
3. Check Environment — Confirm node (18+) is available and OPENCLAW_WORKSPACE is known.
4. Auto-install deps — Run Step 3 if node_modules is missing.
5. Execute — node "$SKILL_DIR/gtts.js" --text "..." --voice "..." --out "..."
6. Confirm Output — Reference the SUCCESS: path and confirm to the user.