pi-speak 🔊

Real-time neural text-to-speech for the Pi coding agent. Speaks assistant responses as they stream — sentence by sentence, with barge-in interruption, multi-session voice arbitration, and studio-quality DSP — powered by a Rust daemon running Kokoro-82M fully in-process via ONNX Runtime.

pi streams tokens ──► speak.ts extension ──► Unix socket ──► pi-speak daemon (Rust)
                                                             ├─ sentence chunker + sanitizer
                                                             ├─ Kokoro-82M ONNX inference (24 kHz)
                                                             ├─ sinc resampler → 48 kHz stereo
                                                             ├─ soft-knee limiter + edge fades
                                                             └─ cpal playback (PipeWire/ALSA)

Features

• Streaming speech — first sentence is spoken while the LLM is still generating (~400 ms time-to-first-audio)
• Barge-in — start typing a new prompt and the current speech stops in < 10 ms
• Multi-session aware — several Pi sessions can talk through one daemon without interleaving; /speak stop silences only your session
• Adaptive chunking — fast first sentence, then 5–10 s prosodic chunks for natural cadence
• Code-aware sanitizer — markdown, code blocks, and ASCII diagrams are summarized or stripped instead of read aloud
• 17 voices — including a blended "JARVIS" British RP voice (60% George / 30% Daniel / 5% Fable / 5% Lewis)
• Tone-aware pacing — subtle speed modulation for questions, warnings, and asides
• Clean handoff DSP — sinc resampling to 48 kHz, soft-knee limiting, S-curve edge fades (no clicks between chunks)

Requirements

• Linux with a working audio output (PipeWire / PulseAudio / ALSA) — macOS mostly works, not battle-tested
• Rust 1.85+ (edition 2024)
• espeak-ng on PATH (phonemization): sudo apt install espeak-ng
• ONNX Runtime shared library (see below)

Install

Pi package (recommended)

pi install npm:@benjaminjamesxyz/pi-speak

That's it. The package's postinstall step downloads the daemon binary, ONNX Runtime, and models (~380 MB total) into ~/.local/share/pi-speak/, then the extension registers itself. Restart Pi and speech just works. Set PI_SPEAK_SKIP_SETUP=1 before installing if you want to provision the native side yourself.

Shell one-liner (no npm)

curl -fsSL https://raw.githubusercontent.com/benjaminjamesxyz/pi-speak/main/install.sh | bash

Installs prerequisites (Rust, espeak-ng), builds the daemon, downloads ONNX Runtime and models (~350 MB), and registers the extension with Pi. Idempotent — safe to re-run to update.

Manual install

git clone https://github.com/benjaminjamesxyz/pi-speak.git
cd pi-speak

# 1. Build the daemon
cargo build --release

# 2. Download models (~350 MB, git-ignored)
bash scripts/download-models.sh

# 3. Make sure ONNX Runtime is findable (any ONE of these works)
export ORT_DYLIB_PATH=/path/to/libonnxruntime.so          # explicit
# …or install a package: apt install libonnxruntime-dev / brew install onnxruntime
# …or copy it to ~/.local/lib/libonnxruntime.so

# 4. (optional) Install the binary so any session can auto-spawn the daemon
cp target/release/pi-speak ~/.local/bin/

pi -e /path/to/pi-speak/extension/speak.ts     # try it out
pi install /path/to/pi-speak                    # or install as a package

Models

Models are not committed to the repo — run scripts/download-models.sh after cloning.

Usage

Speech starts automatically. While the assistant responds, you hear it sentence by sentence.

/speak                toggle mute/unmute for this session
/speak on | off       explicit mute/unmute
/speak stop [all]     stop playback (this session, or every session)
/speak voice <name>   switch voice (jarvis, af_heart, bm_george, am_adam, …)
/speak speed <0.2-4>  speaking rate multiplier
/speak status         daemon status: playing, sessions, model, voice, speed
/speak shutdown       stop the daemon (refuses while other sessions are connected; --force overrides)

Environment variables

Architecture

Two layers:

1. extension/speak.ts — Pi extension. Hooks message_update / message_end / turn_end to stream text deltas to the daemon over a line-delimited JSON Unix-socket protocol; hooks before_agent_start for barge-in; registers /speak. Resolves and auto-spawns the daemon binary if none is running.

2. src/ — Rust daemon (cargo build --release):

   • ipc/ — tokio Unix-socket server; per-connection IDs; flock-guarded single instance; graceful shutdown
   • text/ — streaming sentence chunker (fast-start + sustained modes) and markdown/code sanitizer
   • engine/ — Kokoro-82M ONNX inference in-process via ort; espeak-ng phonemizer with cache; ZIP-of-.npy voice style database; JARVIS blend precomputation
   • dsp/ — rubato sinc resampler (24 kHz → 48 kHz), soft-knee limiter, S-curve edge fades
   • audio/ — cpal output stream with lock-free-ish chunk queue and instant-cancel token

One dedicated producer thread owns the engine and a fair per-session queue map, so sessions never interleave audio and cancellation is O(1).

Development

cargo test        # 17 unit tests (chunker, sanitizer, DSP, engine)
cargo clippy

License

MIT. Model weights keep their upstream licenses (Kokoro: Apache-2.0).