ElevenLabs Voice

Overview

ElevenLabs provides text-to-speech voices for both in-app TTS and phone calls. The config key services.tts.providers.elevenlabs.voiceId controls the voice across all channels. Use the voice_config_update tool to change the voice - it writes to the config file and pushes to the macOS app via SSE in one call.

Choose a Voice

Pick a voice that matches the your identity and the user's preferences. Offer to show the full list if they want to choose themselves.

Female voices

Voice	Style	Voice ID
Amelia	Expressive, enthusiastic, British	ZF6FPAbjXT4488VcRRnw
Sarah	Soft, young, approachable	EXAVITQu4vr4xnSDxMaL
Charlotte	Warm, Swedish-accented	XB0fDUnXU5powFXDhCwa
Alice	Confident, British	Xb7hH8MSUJpSbSDYk0k2
Matilda	Warm, friendly, young	XrExE9yKIg1WjnnlVkGX
Lily	Warm, British	pFZP5JQG7iQjIQuC4Bku

Male voices

Voice	Style	Voice ID
Antoni	Warm, well-rounded	ErXwobaYiN019PkySvjV
Josh	Deep, young, clear	TxGEqnHWrfWFTfGW9XjX
Arnold	Crisp, narrative	VR6AewLTigWG4xSOukaG
Adam	Deep, middle-aged, professional	pNInz6obpgDQGcFmaJgB
Bill	Trustworthy, American	pqHfZKP75CvOlQylNhV4
George	Warm, British, distinguished	JBFqnCBsd6RMkjVDRZzb
Daniel	Authoritative, British	onwK4e9ZLuTAKqWW03F9
Charlie	Casual, Australian	IKne3meq5aSn9XLyUdCD
Liam	Young, articulate	TX3LPaxmHKxFdv7VOQHJ

Setting the voice

To set the chosen voice, use voice_config_update. This writes to the config file (services.tts.providers.elevenlabs.voiceId) for phone calls and pushes to the macOS app via SSE (ttsVoiceId) for in-app TTS in one call:

voice_config_update setting="tts_voice_id" value="<selected-voice-id>"

Verify it worked:

assistant config get services.tts.providers.elevenlabs.voiceId

Tell the user what voice you chose and why, but also offer to show all available voices so they can choose for themselves.

ElevenLabs API Key Setup

For advanced voice selection (browsing the full library, custom/cloned voices), the user needs an ElevenLabs API key. A free tier is available at https://elevenlabs.io.

To collect the API key securely:

credential_store action="prompt" service="elevenlabs" field="api_key"

Advanced Voice Selection (with API key)

Users with an ElevenLabs API key can go beyond the curated list above.

Check for an existing key

assistant credentials inspect --service elevenlabs --field api_key --json

Browse the voice library

curl -s "https://api.elevenlabs.io/v2/voices?category=premade&page_size=50" \
  -H "xi-api-key: $(assistant credentials reveal --service elevenlabs --field api_key)" | python3 -m json.tool

Search for a specific style

curl -s "https://api.elevenlabs.io/v2/voices?search=warm+female&page_size=10" \
  -H "xi-api-key: $(assistant credentials reveal --service elevenlabs --field api_key)" | python3 -m json.tool

Custom and cloned voices

If the user has created a custom voice or voice clone in their ElevenLabs account, they can use its voice ID directly. These voices work in both in-app TTS and Twilio ConversationRelay.

Preview voices

Each voice in the API response includes a preview_url with an audio sample the user can listen to before deciding.

Set the chosen voice

After the user picks a voice from the library:

voice_config_update setting="tts_voice_id" value="<selected-voice-id>"

Voice Tuning

Fine-tune how the selected voice sounds. These parameters apply to all ElevenLabs modes (in-app TTS and phone calls):

# Playback speed (0.7 = slower, 1.0 = normal, 1.2 = faster)
assistant config set services.tts.providers.elevenlabs.speed 1.0

# Stability (0.0 = more expressive/variable, 1.0 = more consistent/monotone)
assistant config set services.tts.providers.elevenlabs.stability 0.5

# Similarity boost (0.0 = more creative, 1.0 = closer to original voice)
assistant config set services.tts.providers.elevenlabs.similarityBoost 0.75

Lower stability makes the voice more expressive but less predictable - good for conversational calls. Higher stability is better for scripted or formal contexts.

Voice Model Tuning

By default, the system sends a bare voiceId to Twilio ConversationRelay (no model/tuning suffix). This is the safest default across voice IDs.

To optionally force Twilio's extended voice spec, set a model ID:

assistant config set services.tts.providers.elevenlabs.voiceModelId "flash_v2_5"

When voiceModelId is set, the emitted voice string becomes: voiceId-model-speed_stability_similarity.

To clear and revert to the bare voiceId default:

assistant config set services.tts.providers.elevenlabs.voiceModelId ""