STT2TTS

Local-first speech-to-text and text-to-speech MCP server. Hot-swappable engines via config.yaml — no code changes, no API keys required.

┌──────────────┐     stdio      ┌──────────────────┐
│ MCP client   │ ◀────────────▶ │ stt2tts-mcp      │
│              │                │  ├─ STT engine   │ ──▶ faster-whisper
│              │                │  └─ TTS engine   │ ──▶ piper / kokoro / coqui
└──────────────┘                └──────────────────┘
                                       │
                                       ▼
                              config.yaml (hot-reload)

Why

Replaces whisper-mcp. Works offline, ships with five STT and six TTS engines, switches per-task via config.

Install

pip install stt2tts-mcp

# Add the engines you actually use:
pip install stt2tts-mcp[stt-faster-whisper]   # local STT
pip install stt2tts-mcp[tts-piper]            # local TTS (~50MB voices)

# Register with your MCP client (consult your client's docs for the exact
# config file location — most use mcp_config.json or a per-client equivalent):
{
  "mcp": {
    "stt2tts": {
      "type": "local",
      "command": ["stt2tts-mcp"],
      "enabled": true
    }
  }
}

Engines

Configure

config.yaml:

stt:
  engine: faster_whisper   # sherpa_onnx | openai_api | ollama | lmstudio
  enabled: true
  params:
    model_size: base.en     # tiny.en | base.en | small.en | medium.en
    device: cpu             # cpu | cuda

tts:
  engine: piper             # kokoro | coqui | openai_api | ollama | lmstudio
  enabled: true
  params:
    voice: en_US-lessac-medium
    model_dir: ~/.cache/piper

Reload without restart by calling the reload_config MCP tool.

MCP Tools

All formats ffmpeg supports (wav, mp3, ogg, flac, m4a) are accepted; STT input is auto-converted to 16 kHz mono.

Develop

Source-only releases ship on main for clean installs. The dev branch carries the test suite (tests/test_config_loader.py, tests/test_mcp_integration.py, tests/test_piper_no_json.py) for contributors.

git clone https://github.com/pygodzilla/stt2tts-mcp
cd stt2tts-mcp
git checkout dev                 # for tests + dev iteration
pip install -e ".[all]"
python -m stt2tts_mcp.server

License

MIT