Local, on-device text-to-speech for Claude & Cursor. No API key, no cloud. Powered by Supertonic 3 — 10
voices, 31 languages, inline expression tags (<laugh>, <pause>, etc.). ~820ms synthesis on Apple Silicon. MIT licensed.
Overview
What it does
Give your AI assistant a voice — locally, with no API key and no cloud calls. supertonic3-mcp wraps Supertonic 3 on-device TTS as three MCP tools your AI assistant (Claude Desktop, Cursor, or any MCP client) can call directly.
Tools
| Tool | Description |
|---|---|
speak | Synthesize text to WAV. Returns file path + metadata. |
list_voices | List built-in voices (M1–M5, F1–F5) |
list_expressions | List inline expression tags with descriptions |
Key features
- No API key — runs entirely on your machine
- No cloud — model weights cached locally (~400MB, downloads once)
- 10 voices — M1–M5, F1–F5
- 31 language codes —
en,ko,ja,fr, and more - Inline expression tags —
<laugh>,<pause>,<breath>, and 7 more - ~820ms warm synthesis on Apple M3 Air
- FastMCP + asyncio — inference serialized behind asyncio.Lock; playback runs outside the lock
Quick start
git clone https://github.com/nextic-tech/supertonic3-mcp
cd supertonic3-mcp
pip install -e .
supertonic3-mcp preload # optional: pre-download model
Add to your MCP config:
{
"mcpServers": {
"supertonic3": {
"command": "/absolute/path/to/supertonic3-mcp/.venv/bin/supertonic3-mcp",
"args": []
}
}
}
License
MIT (code) · model weights © Supertone Inc. under OpenRAIL-M
Server Config
{
"mcpServers": {
"supertonic3": {
"command": "uvx",
"args": [
"supertonic3-mcp"
]
}
}
}