McSpeak

Multi-engine text-to-speech server exposed as MCP tools via FastMCP 3.0 Streamable HTTP. Plays audio through the host's speakers using PipeWire. Built for giving AI agents a voice -- literally.

Quick Start

McSpeak runs a Streamable HTTP MCP server on :8371. Start the server, then point any MCP client at it.

1. Get the Kokoro model files (~340 MB, one-time):

mkdir -p models/kokoro && cd models/kokoro
curl -LO https://github.com/thewh1teagle/kokoro-onnx/releases/download/model-files-v1.0/kokoro-v1.0.onnx
curl -LO https://github.com/thewh1teagle/kokoro-onnx/releases/download/model-files-v1.0/voices-v1.0.bin
cd -

The defaults look for models/kokoro/kokoro-v1.0.onnx and models/kokoro/voices-v1.0.bin relative to the working directory. Override with TTS_KOKORO_MODEL / TTS_KOKORO_VOICES if you put them elsewhere.

2. Start the server:

# Run directly from PyPI (no install needed)
uvx mcspeak

# Or install and run
pip install mcspeak
mcspeak

Wait for McSpeak ready on 0.0.0.0:8371 in the logs. Piper and Orpheus will report unhealthy unless their backends are running -- that's expected; Kokoro alone is enough to start.

3. Wire it into Claude Code (HTTP transport, server must be running):

claude mcp add --transport http mcspeak http://127.0.0.1:8371/mcp

mcspeak ships as a Streamable HTTP server, not a stdio one, so --transport http is required. The older form claude mcp add mcspeak -- uvx mcspeak registers stdio and will fail to connect.

For multi-engine Docker deployment with Piper and GPU-accelerated Orpheus, see Docker Setup below.

MCP Tools

Tool	What it does
speak	Synthesize text and play through speakers. Blocks with live progress.
generate_audio	Synthesize to WAV file without playing. Bypasses the queue.
list_voices	List available voices for an engine.
list_engines	Show all engines and their health status.
speech_status	Check status of a queued/playing speech item.
cancel_speech	Kill playback immediately. Plays a cancel tone.

There's also an audio://recent resource listing the last 20 generated WAV files.

Engines

Engine	Backend	Speed	Voices	Notes
kokoro	ONNX (local CPU)	~4x realtime	~50	Default. Fast, good quality.
piper	Wyoming protocol (Docker)	~2x realtime	Depends on model	Connects to any Wyoming-compatible TTS server.
orpheus	llama-server + SNAC	~1x realtime	6	LLM-based. Supports <laugh>, <sigh>, emotion tags. Needs GPU.

Features

Radio-Style Alert Tones

Speech is bookended by short tones inspired by two-way radio systems. An entry tone fires immediately when speak() is called (before synthesis starts), acting as an audible "I heard you" that covers the 1-3s synthesis latency. An exit tone plays when the queue empties.

Available tones: chirp (Nextel iDEN), apollo (NASA quindar key-up), roger (CB radio descending beep), quindar-out (NASA unkey), scratch (vinyl record scratch for cancellation), and more. All generated programmatically at startup -- no bundled audio files.

Voice Identity

When multiple projects connect simultaneously, each one automatically gets a distinct voice via round-robin assignment from a curated pool. Voices are interleaved across gender and accent (American, British, European) for maximum contrast. Assignments persist across restarts.

Pass project="my-project" in speak() calls, or let it auto-detect from MCP Roots.

Media Ducking

External audio (YouTube, Spotify, etc.) automatically fades down before speech and fades back in after the exit tone, like a radio broadcast interruption. Uses pactl under the hood. Fails silently if PulseAudio isn't available.

Chunked Synthesis Pipeline

Long texts (20+ words with sentence boundaries) are split into chunks and pipelined -- synthesis of chunk N+1 overlaps playback of chunk N. First audio plays within ~1-2s instead of waiting for the full text to synthesize.

Graceful Shutdown

docker compose down lets the current speech finish instead of cutting mid-sentence. Two-phase: 3s handler drain, then up to 30s for the consumer to finish. Configurable via TTS_SHUTDOWN_TIMEOUT.

Configuration

All settings use the TTS_ prefix and can be set via environment variables or .env file.

Variable	Default	Description
TTS_HOST	0.0.0.0	Server bind address
TTS_PORT	8371	Server port
TTS_ENTRY_TONE	chirp	Tone before speech (chirp, apollo, none, or WAV path)
TTS_EXIT_TONE	roger	Tone after speech (roger, quindar-out, none, or WAV path)
TTS_CANCEL_TONE	scratch	Tone on cancel (scratch, reverse-roger, none, or WAV path)
TTS_DUCK_MEDIA	true	Fade external audio during speech
TTS_DUCK_FADE_OUT_MS	500	Media fade-out duration (ms)
TTS_DUCK_FADE_IN_MS	1000	Media fade-in duration (ms)
TTS_VOICE_IDENTITY	true	Auto-assign distinct voices per project
TTS_VOICE_IDENTITY_FILE	(empty)	JSON file to persist voice assignments
TTS_VOICE_IDENTITY_EXCLUDE	af_nicole	Voices excluded from auto-assign pool
TTS_ANNOUNCE_PROJECT	false	Prefix speech with project name
TTS_VOICE_BLACKLIST	am_adam,af_jessica	Voices hidden from listings
TTS_SHUTDOWN_TIMEOUT	30	Max seconds to wait for speech on shutdown
TTS_KOKORO_MODEL	models/kokoro/kokoro-v1.0.onnx	Path to Kokoro ONNX model
TTS_KOKORO_VOICES	models/kokoro/voices-v1.0.bin	Path to Kokoro voice pack
TTS_PIPER_HOST	172.26.0.3	Piper Wyoming server host
TTS_PIPER_PORT	10200	Piper Wyoming server port
TTS_ORPHEUS_URL	http://127.0.0.1:8081	Orpheus llama-server URL

Docker Setup

The compose file defaults to a kokoro-only stack — no GPU required. Orpheus (GPU-accelerated, llama-server backed) is opt-in via the with-orpheus profile. Piper integrates via its host/port settings; you supply your own Wyoming server.

Prerequisites (base, kokoro-only):

• PipeWire on the host (the container plays audio via the host's pw-play socket)
• An external Docker network named caddy (create with docker network create caddy if it doesn't exist). The private mcspeak-internal network is auto-created per-stack.
• Kokoro ONNX model files in ./models/kokoro/ (see Quick Start for the download)

Additional prerequisites for with-orpheus:

• NVIDIA GPU + nvidia-container-toolkit
• Orpheus GGUF model on disk — path goes in .env as ORPHEUS_GGUF_PATH

Bring it up (kokoro-only):

make up        # build + start kokoro-only
make logs      # follow logs
make status    # health check

Bring it up with Orpheus:

cp .env.example .env
# Edit .env: set ORPHEUS_GGUF_PATH to your Orpheus GGUF file
make up-with-orpheus

Once make status shows the container as healthy, register it with Claude Code. The compose file applies a caddy-docker-proxy label exposing the server at mctalkbox.l.supported.systems -- if you're not using that hostname, point at the container's mapped port directly:

# Direct connection (replace with your hostname/port if different)
claude mcp add --transport http mcspeak http://127.0.0.1:8371/mcp

The container mounts the host PipeWire socket (/run/user/1000/pipewire-0) for audio playback and the PulseAudio compat socket (/run/user/1000/pulse) for media ducking.

stop_grace_period in the compose file is set to 38s (3s drain + 30s shutdown timeout + 5s safety). Adjust if you change TTS_SHUTDOWN_TIMEOUT.

Architecture

src/tts_mcp/
  server.py          FastMCP lifespan, tool definitions, chunked synthesis
  queue.py           Producer-consumer speech queue with priority + outcome tracking
  tones.py           Procedural tone WAV generation (numpy, 48kHz 16-bit PCM)
  audio.py           WAV writing and async pw-play wrapper
  media_duck.py      Async pactl volume control for media ducking
  voice_identity.py  Project-to-voice mapping with round-robin assignment
  settings.py        Pydantic settings from env vars
  engines/
    base.py          TTSEngine abstract base
    kokoro.py        Kokoro ONNX engine
    piper.py         Wyoming protocol client
    orpheus.py       llama-server + SNAC decoder

See CLAUDE.md for the full technical reference -- design decisions, progress lifecycle, cancellation semantics, and the Python 3.13 asyncio.wait_for pitfall that cost a few hours of debugging.

License

MIT