Case 00442

VoiceClaw

Local-only voice I/O for OpenClaw agents.

• STT: transcribe.sh — converts audio to text via local Whisper binary
• TTS: speak.sh — converts text to speech via local Piper binary
• Network calls: none — both scripts run fully offline
• No cloud APIs, no API keys required

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Prerequisites

The following must be installed on the system before using this skill:

Requirement	Purpose
whisper binary	Speech-to-text inference
ggml-base.en.bin model file	Whisper STT model
piper binary	Text-to-speech synthesis
*.onnx voice model files	Piper TTS voices
ffmpeg	Audio format conversion

See README.md for installation and setup instructions.

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Environment Variables

Variable	Default	Purpose
WHISPER_BIN	auto-detected via which	Path to whisper binary
WHISPER_MODEL	~/.cache/whisper/ggml-base.en.bin	Path to Whisper model file
PIPER_BIN	auto-detected via which	Path to piper binary
VOICECLAW_VOICES_DIR	~/.local/share/piper/voices	Directory containing .onnx voice model files

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Verify Setup

which whisper && echo "STT binary: OK"
which piper   && echo "TTS binary: OK"
which ffmpeg  && echo "ffmpeg: OK"
ls "${WHISPER_MODEL:-$HOME/.cache/whisper/ggml-base.en.bin}" && echo "STT model: OK"
ls "${VOICECLAW_VOICES_DIR:-$HOME/.local/share/piper/voices}"/*.onnx 2>/dev/null | head -1 && echo "TTS voices: OK"

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Inbound Voice: Transcribe

# Transcribe audio → text (supports ogg, mp3, m4a, wav, flac)
TRANSCRIPT=$(bash scripts/transcribe.sh /path/to/audio.ogg)

Override model path:

WHISPER_MODEL=/path/to/ggml-base.en.bin bash scripts/transcribe.sh audio.ogg

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Outbound Voice: Speak

# Step 1: Generate WAV (local Piper — no network)
WAV=$(bash scripts/speak.sh "Your response here." /tmp/reply.wav en_US-lessac-medium)

# Step 2: Convert to OGG Opus (Telegram voice requirement)
ffmpeg -i "$WAV" -c:a libopus -b:a 32k /tmp/reply.ogg -y -loglevel error

# Step 3: Send via message tool (filePath=/tmp/reply.ogg)

Override voice directory:

VOICECLAW_VOICES_DIR=/path/to/voices bash scripts/speak.sh "Hello." /tmp/reply.wav

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Available Voices

Voice	Style
en_US-lessac-medium	Neutral American (default)
en_US-amy-medium	Warm American female
en_US-joe-medium	American male
en_US-kusal-medium	Expressive American male
en_US-danny-low	Deep American male (fast)
en_GB-alba-medium	British female
en_GB-northern_english_male-medium	Northern British male

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Agent Behavior Rules

1. Voice in → Voice + Text out. Always respond with both a voice reply and a text reply when a voice message is received.
2. Include the transcript. Show "🎙️ I heard: [transcript]" at the top of every text reply to a voice message.
3. Keep voice responses concise. Piper TTS works best under ~200 words — summarize for audio, include full detail in text.
4. Local only. Never use a cloud TTS/STT API. Only the local whisper and piper binaries.
5. Send voice before text. Send the audio file first, then follow with the text reply.

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Full Example

# 1. Transcribe inbound voice message
TRANSCRIPT=$(bash path/to/voiceclaw/scripts/transcribe.sh /path/to/voice.ogg)

# 2. Compose reply and generate audio
RESPONSE="Deployment complete. All checks passed."
WAV=$(bash path/to/voiceclaw/scripts/speak.sh "$RESPONSE" /tmp/reply_$$.wav)
ffmpeg -i "$WAV" -c:a libopus -b:a 32k /tmp/reply_$$.ogg -y -loglevel error

# 3. Send voice + text
# message(action=send, filePath=/tmp/reply_$$.ogg, ...)
# reply: "🎙️ I heard: $TRANSCRIPT\n\n$RESPONSE"

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Troubleshooting

Issue	Fix
whisper: command not found	Ensure whisper binary is installed and in PATH
Whisper model not found	Set WHISPER_MODEL=/path/to/ggml-base.en.bin
piper: command not found	Ensure piper binary is installed and in PATH
Voice model missing	Set VOICECLAW_VOICES_DIR=/path/to/voices/
OGG won't play on Telegram	Ensure -c:a libopus flag in ffmpeg command