hope-voice-api/AGENTS.md

# Voice — Real-time Voice Assistant

A single-container voice assistant built on LiveKit Agents. Speaks and listens in real time using Azure Speech (STT + TTS) with models hosted by OpenWebUI (xNAS) for reasoning.

## Architecture

One Docker container runs four processes via supervisord:

1. **LiveKit server** — open-source WebRTC media transport (port 7880 TCP, 7882 UDP muxed media)
2. **Voice agent** — Python LiveKit Agents pipeline: Azure STT → LLM (OpenWebUI) → Azure TTS
3. **Web frontend** — static HTML served by nginx (port 9178 by default)
4. **Media server** — FastAPI music library/player coordinator (port 8092 internal, proxied at /media/api/)

```
Browser ──WebRTC──► LiveKit Server ──audio──► Agent
   ▲                                              │
   └────────── audio ◄────────────────────────────┘
                        Azure STT → LLM (OpenWebUI) → Azure TTS

Browser ──HTTP──► nginx /media/api/ ──► Media server ──► yt-dlp/ffmpeg ──► ./media
   └────── audio element ◄── /media/files/ (nginx static, Range) ──────────┘
```

## Quick Start

```bash
# 1. Set your Azure Speech key (already in ~/.hermes/.env as AZURE_SPEECH)
export AZURE_SPEECH_KEY=$(grep '^AZURE_SPEECH=' ~/.hermes/.env | cut -d= -f2)

# 2. Build and start
docker compose up --build -d

# 3. Open the web UI (self-signed cert: accept the browser warning once)
# https://<host-ip>:9178
```

LAN access requires firewall rules: `9178/tcp` (UI + signaling), `7882/udp`
(WebRTC media), `7881/tcp` (media TCP fallback).

## Ports

| Port  | Protocol | Service              | Access       |
|-------|----------|----------------------|--------------|
| 7880  | TCP      | LiveKit HTTP/WS      | internal only (proxied via nginx at /livekit/) |
| 7881  | TCP      | LiveKit RTC media (TCP fallback) | LAN |
| 7882  | UDP      | LiveKit RTC media (muxed) | LAN   |
| 8092  | TCP      | Media server (library, player state, stream proxy) | internal only (proxied via nginx at /media/api/) |
| 9178  | TCP      | Web frontend (HTTPS) | LAN          |

## Configuration

All config lives in `.env` (git-ignored). See `.env.example` for the full list.

Key variables:
- `AZURE_SPEECH_KEY` — Azure Speech resource key
- `AZURE_SPEECH_REGION` — default `eastus`
- `AZURE_TTS_VOICE` — default voice (`en-US-Ava:DragonHDOmniLatestNeural`)
- `LLM_BASE_URL` — OpenAI-compatible endpoint (default `http://192.168.86.2:3005/api`, OpenWebUI)
- `LLM_MODEL` — default model (default `qwen2.5-vl-3b`; switchable live from the web UI)
- `LLM_API_KEY` — OpenWebUI API key (bears `sk-…`)
- `YTDLP_COOKIES` — optional path to a cookies.txt inside the container (e.g. `/data/media/cookies.txt`) for reliable YouTube downloads

## Media Player

Hope can play music on the web UI's media player: YouTube Music search →
yt-dlp download → ffmpeg transcode to mp3 → nginx static streaming (HTTP
Range) back to the browser's `<audio>` element. Live audio stream URLs
(internet radio) are added to the library and proxied over HTTPS by the
media server (mixed-content safe).

- The permanent library lives in `./media` (bind-mounted to `/data/media`):
  `files/` mp3s, `thumbs/` cover art, `jobs/` download status, `library.json`.
- `web/media_server.py` owns the library, search, download jobs (one at a
  time), and per-room player desired state. The browser is the actual player:
  it polls `GET /media/api/state?room=…`, reconciles, and reports real
  playback back via `POST /media/api/report`.
- Hope's tools live in `agent/media_mcp.py` (MCP, id "media"):
  `search_music`, `play_song`, `offer_song_choices`, `pause_music`,
  `resume_music`, `stop_music`, `skip_song`, `seek_music`, `now_playing`,
  `list_library`, `add_stream`. The MCP process is spawned per session with
  `MEDIA_ROOM` set to the LiveKit room name, scoping player state per room.
- **Music and conversation are mutually exclusive.** When a track plays, the
  UI reports `{type: "media_state", state: "playing"}` on data-channel topic
  "media-control" and the agent disables its mic (`_apply_listening` in
  agent.py). Engaging Hope (Start conversation / text message) pauses the
  music; ending the conversation resumes what was playing. Voice commands
  (pause/skip/…) work whenever the conversation is active.

## Voice Selection

The web UI includes a voice picker that sends the selected voice to the agent via LiveKit data channel. The agent updates its TTS voice in real time without restarting.

Supported voices: any Azure Neural voice. See https://learn.microsoft.com/en-us/azure/ai-services/speech-service/language-support?tabs=en-us#neural-voices

## SSML / Expressive Speech

The TTS layer wraps output in SSML. The default Azure Dragon HD Omni voice recognizes inline style markers such as `[appreciative]`, `[whispering]`, and `[Neutral]`; the agent prompt allows these markers while keeping responses short and conversational.

## Agent Prompt

The LLM is instructed to:
- Speak as if talking to someone, not writing for them to read
- Keep responses to 1-3 sentences
- Use contractions, natural fillers sparingly
- Never use markdown, lists, or formatting
- Spell out numbers and abbreviations

## Testing

```bash
# Verify the container is running
docker compose ps

# Check all logs (single service: "voice")
docker compose logs -f voice

# Tail individual process logs via supervisord stdout
docker exec voice tail -f /dev/stdout

# Test TTS directly (outside the agent)
curl -s "https://eastus.tts.speech.microsoft.com/cognitiveservices/v1" \
  -H "Ocp-Apim-Subscription-Key: $AZURE_SPEECH_KEY" \
  -H "Content-Type: application/ssml+xml" \
  -H "X-Microsoft-OutputFormat: audio-24khz-48kbitrate-mono-mp3" \
  --data-binary '<speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xml:lang="en-US"><voice name="en-US-Ava:DragonHDOmniLatestNeural">[appreciative] Test complete.</voice></speak>' > /tmp/test.mp3
```

## File Layout

```
~/dev/voice/
├── AGENTS.md            ← you are here
├── .env.example         ← config template (copy to .env)
├── .gitignore
├── docker-compose.yml   ← single container
├── Dockerfile           ← multi-stage build
├── entrypoint.sh        ← regenerates self-signed cert with LAN IP at start
├── livekit.yaml         ← LiveKit server config
├── nginx.conf           ← HTTPS UI + /livekit/ WS proxy + /media/ (static + API)
├── supervisord.conf     ← process manager (livekit, agent, nginx, token-server, media-server)
├── certs/               ← persisted self-signed cert (volume mount)
├── media/               ← permanent music library (bind-mounted to /data/media)
│   ├── files/           ← transcoded mp3 tracks (nginx-served, HTTP Range)
│   ├── thumbs/          ← cover art
│   ├── jobs/            ← download job status snapshots
│   └── library.json     ← library metadata (permanent)
├── agent/
│   ├── agent.py         ← LiveKit Agents voice pipeline
│   ├── media_mcp.py     ← Hope's music tools (YouTube Music via media server)
│   ├── pyproject.toml   ← Python deps (uv)
│   └── uv.lock          ← locked dependency versions
└── web/
    ├── index.html       ← single-page voice UI (+ music panel)
    ├── app.js           ← LiveKit client logic (+ player reconciliation)
    ├── media_server.py  ← FastAPI library/search/download/player state
    ├── token_server.py  ← LiveKit token endpoint (mints room name)
    ├── manifest.json    ← PWA manifest
    ├── favicon.svg      ← site icon
    ├── livekit-client.umd.js ← vendored LiveKit JS SDK (no CDN)
    └── style.css        ← minimal dark theme
```

## Conventions

- **Single container.** All services (LiveKit, agent, web, token endpoint) run in one Docker container via supervisord. No multi-service compose.
- **No published UDP ports in compose.** LiveKit binds its media ports directly on the host network (`network_mode: host`). This avoids the docker-proxy process explosion that hit hope-webui.
- **Agent dispatch via roomConfig token claim.** LiveKit only dispatches agents to rooms that request them; a room auto-created by a participant join gets none. The token endpoint embeds `roomConfig.agents` in every JWT so the agent is dispatched when the browser joins. Do not pre-create rooms instead — if the agent worker isn't registered yet (first ~15s after container start), the dispatch silently fails and never retries; joining later re-fires it. The token server now pins the room name to "voice-room" server-side and no longer accepts arbitrary room names.
- **Interruption mode must be "vad".** `interruption={"mode": "adaptive"}` requires the LiveKit Cloud barge-in service (agent-gateway.livekit.cloud) and spams 401 retries on self-hosted setups.
- **Mic requires HTTPS.** Browsers block getUserMedia outside a secure context. nginx serves the UI on `WEB_PORT` (9178 by default) over HTTPS with a self-signed cert whose SAN includes the detected LAN IP. The cert is persisted in `./certs/` and the LiveKit WS is proxied through nginx at `/livekit/`.
- **No CDN dependencies.** livekit-client UMD bundle is vendored into `web/`; LAN devices may have no internet access.
- **Transcripts flow over the data channel.** The agent publishes `{type: "transcript", role, text}` JSON on topic "transcript"; the UI renders them. Voice changes flow the other way as `{type: "set_voice", voice}` on topic "voice-control".
- **Models come from OpenWebUI.** The LLM endpoint is OpenWebUI's OpenAI-compatible API at `LLM_BASE_URL` (default `http://192.168.86.2:3005/api`); chat goes to `/api/chat/completions` and the model list comes from `GET {LLM_BASE_URL}/models`. Plain `/v1/*` routes are NOT routed on that instance (they serve the SPA). Pipe models (`opencode_go_messages.*`, `go-chat.*`, `go-responses.*`) currently fail upstream with auth errors; the local llama.cpp/vLLM models (e.g. `gemma-4-e4b`, `qwen2.5-vl-3b`, `qwen3.8-27b`) work.
- **Reasoning models may hide their answer.** Gemma (and similar) sometimes spends tokens on hidden reasoning before producing content. The agent implements this with `max_completion_tokens=1000` and a `HopeLLM` subclass that wraps the LLM stream, falling back to `reasoning_content` if `content` is empty.
- **Azure TTS uses SSML, not JSON.** The REST endpoint requires `Content-Type: application/ssml+xml`. The LiveKit Azure plugin handles this internally.
- **Voice changes are live.** The web UI sends a data message to the agent; the agent calls `tts.update_options(voice=...)` without restarting. The agent filters data messages by topic ("voice-control") before processing.
- **Model changes are live too.** The agent fetches the chat-capable model list (`HopeLLM` filters out embedding/reranker ids) and publishes `{type: "models", models, selected}`; the UI's settings sheet renders a picker and sends `{type: "set_model", model}`, which calls `HopeLLM.update_options(model=...)` (mutates `self._opts.model`) and acks with `{type: "model_changed", model}`. The choice persists in the browser's localStorage.
- **All supervisord programs log to /dev/stdout** so `docker compose logs -f voice` shows everything. Individual process logs are no longer written to files.
- **Music downloads are mp3, not YouTube streams.** The media server transcodes with yt-dlp (`-x --audio-format mp3 --audio-quality 192K --embed-thumbnail`) into `/data/media/files/{video_id}.mp3`; nginx serves those files as statics with native HTTP Range, which is what makes seeking work in the `<audio>` element. Never point the player at YouTube directly.
- **External stream URLs are proxied, never played directly.** An `http://` radio URL would be blocked as mixed content on the HTTPS UI, so `GET /media/api/stream/{id}` re-serves the upstream over HTTPS with Range passthrough. Downloaded tracks on that endpoint just redirect to `/media/files/`.
- **Player state is per-room desired state, reconciled by the browser.** The media server never streams to anything; it records what SHOULD play per LiveKit room and the browser polls and reports back. Track ids for YouTube tracks are the video ids (dedupe by video_id); stream tracks get `s<uuid>`.
- **Anonymous yt-dlp first, cookies when flaky.** Search (`ytsearch`) and downloads work anonymously from a residential IP; if YouTube starts bot-blocking, drop a cookies.txt into `./media/cookies.txt` and set `YTDLP_COOKIES=/data/media/cookies.txt`.

## Git

Commit frequently. Conventional commits (`feat:`, `fix:`, `chore:`).