Voice & TTS

Hermes Agent supports both text-to-speech output and voice message transcription across all messaging platforms.

Text-to-Speech

Convert text to speech with three providers:

Provider	Quality	Cost	API Key
Edge TTS (default)	Good	Free	None needed
ElevenLabs	Excellent	Paid	ELEVENLABS_API_KEY
OpenAI TTS	Good	Paid	VOICE_TOOLS_OPENAI_KEY

Platform Delivery

Platform	Delivery	Format
Telegram	Voice bubble (plays inline)	Opus .ogg
Discord	Audio file attachment	MP3
WhatsApp	Audio file attachment	MP3
CLI	Saved to ~/.hermes/audio_cache/	MP3

Configuration

# In ~/.hermes/config.yaml
tts:
  provider: "edge"              # "edge" | "elevenlabs" | "openai"
  edge:
    voice: "en-US-AriaNeural"   # 322 voices, 74 languages
  elevenlabs:
    voice_id: "pNInz6obpgDQGcFmaJgB"  # Adam
    model_id: "eleven_multilingual_v2"
  openai:
    model: "gpt-4o-mini-tts"
    voice: "alloy"              # alloy, echo, fable, onyx, nova, shimmer

Telegram Voice Bubbles & ffmpeg

Telegram voice bubbles require Opus/OGG audio format:

• OpenAI and ElevenLabs produce Opus natively — no extra setup
• Edge TTS (default) outputs MP3 and needs ffmpeg to convert:

# Ubuntu/Debian
sudo apt install ffmpeg

# macOS
brew install ffmpeg

# Fedora
sudo dnf install ffmpeg

Without ffmpeg, Edge TTS audio is sent as a regular audio file (playable, but shows as a rectangular player instead of a voice bubble).

tip

If you want voice bubbles without installing ffmpeg, switch to the OpenAI or ElevenLabs provider.

Voice Message Transcription

Voice messages sent on Telegram, Discord, WhatsApp, or Slack are automatically transcribed and injected as text into the conversation. The agent sees the transcript as normal text.

Provider	Model	Quality	Cost
OpenAI Whisper	whisper-1 (default)	Good	Low
OpenAI GPT-4o	gpt-4o-mini-transcribe	Better	Medium
OpenAI GPT-4o	gpt-4o-transcribe	Best	Higher

Requires VOICE_TOOLS_OPENAI_KEY in ~/.hermes/.env.

Configuration

# In ~/.hermes/config.yaml
stt:
  enabled: true
  model: "whisper-1"