Real-time Voice (MLLM)

# Agora Conversational AI — Realtime Recipe (Python)

[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](./LICENSE)
[![Python](https://img.shields.io/badge/python-%3E%3D3.10-blue)](https://www.python.org/)
[![Bun](https://img.shields.io/badge/bun-latest-black)](https://bun.sh/)

The **realtime** recipe in the Agora Conversational AI recipes family.
Voice-to-voice conversation using a single **OpenAI Realtime** MLLM — no separate
STT, LLM, or TTS. Speak, and hear the model respond directly.

**Not zero-key** — `OPENAI_API_KEY` with Realtime API access is required.

**Pipeline:** `OpenAIRealtime` MLLM via `.with_mllm()` (server_vad turn detection)

## Prerequisites

- [Python 3.10+](https://www.python.org/)
- [Bun](https://bun.sh/)
- [Agora CLI](https://github.com/AgoraIO/cli) — makes generating an App ID + App Certificate easy
- **OpenAI API key with Realtime API access** — set as `OPENAI_API_KEY` in `server/.env.local`

The same commands work on macOS, Linux, and Windows. On macOS/Linux, setup uses
`python3`; on Windows, it uses the Python launcher (`py`) or `python`. WSL and
virtualenv activation are not required.

## Run It

```bash
# 1. Install web deps + create the Python venv
bun run setup

# 2. Add Agora credentials (CLI), or edit server/.env.local by hand
agora login
agora project use <your-project>          # select which project to use
agora project env write server/.env.local # writes App ID + Certificate

# 3. Add your OpenAI Realtime API key to server/.env.local
#    OPENAI_API_KEY=sk-...   (required — OpenAI Realtime access)
#    OPENAI_MODEL=gpt-4o-realtime-preview  (optional, this is the default)

# 4. Run backend + web
bun run dev
```

Open [http://localhost:3000](http://localhost:3000) → **Start Conversation** → speak.

### Working from a clone

If you cloned this repo (rather than scaffolding via the Agora CLI), the steps
above are complete as written: `bun run setup` creates the Python venv and
installs web dependencies, then `bun run dev` brings up both services. You
still need Agora credentials and `OPENAI_API_KEY` in `server/.env.local` before
a conversation can connect.

Services:

- Frontend — http://localhost:3000
- Backend — http://localhost:8000
- Mock LLM — N/A (the realtime MLLM handles voice end-to-end)
- API docs — http://localhost:8000/docs

## Deploy

Deploy `web` (Next.js) and `server` (a reachable FastAPI backend). Set
`AGENT_BACKEND_URL` in the web deployment so the Next rewrites reach the backend.

A backend-only Docker image is published to
`ghcr.io/AgoraIO-Conversational-AI/recipe-agent-realtime` on `v*` tags.
It exposes **BACKEND-ONLY** (:8000). No separate service is needed.

## Environment variables

Backend env file: [`server/.env.example`](https://github.com/AgoraIO-Conversational-AI/recipe-agent-realtime/blob/main/server/.env.example).

| Variable | Required | Default | Notes |
| --- | :---: | :---: | --- |
| `AGORA_APP_ID` | ✅ | — | Agora Console → Project → App ID |
| `AGORA_APP_CERTIFICATE` | ✅ | — | Agora Console → Project → App Certificate |
| `OPENAI_API_KEY` | ✅ | — | BYO OpenAI key with Realtime API access. Validated at agent start. |
| `OPENAI_MODEL` | | `gpt-4o-realtime-preview` | OpenAI Realtime model name |
| `AGENT_GREETING` | | built-in | Optional opening line override |

## Commands

```bash
bun run setup            # install web deps + create server/ venv
bun run dev              # run backend (:8000) + web (:3000)

bun run doctor           # prerequisite check (no creds needed)
bun run doctor:local     # + .env.local + credentials checks

bun run verify           # web-only gate (no Agora creds needed)
bun run verify:local     # full local gate: backend compile + smoke tests + web build
bun run clean            # remove venvs and build artifacts
```

Tests run standalone (no Agora cloud needed): `pytest` in `server/`, plus
`bun run verify` in `web/`. CI runs them on Linux/macOS/Windows × Python 3.10 & 3.13.

## Architecture

```
Browser (localhost:3000)
  │  fetch /api/*
  ▼
Next.js  ──rewrite──▶  Agent backend  (server/, localhost:8000)
                          │  starts agent session (OpenAIRealtime MLLM)
                          ▼
                       Agora ConvoAI Cloud
                          │  OpenAI Realtime (voice-to-voice, server_vad)
                          ▼
                       User hears realtime voice response
```

No cascading STT/LLM/TTS vendors. No `llm/` service.
See [ARCHITECTURE.md](https://github.com/AgoraIO-Conversational-AI/recipe-agent-realtime/blob/main/ARCHITECTURE.md).

## What You Get

- A **Next.js** web client (:3000) that drives the RTC/RTM lifecycle and only ever calls `/api/*`.
- A **FastAPI** agent backend (:8000) that owns Agora token generation and the agent session lifecycle.
- The `/api/get_config` · `/api/startAgent` · `/api/stopAgent` contract between the web client and the backend (Next rewrites, no Route Handlers).
- **OpenAI Realtime MLLM** attached via `.with_mllm()` — replaces the cascading STT→LLM→TTS with a single voice-to-voice model.
- **Server-side VAD** (`server_vad`) turn detection — owned by the MLLM, no top-level cascading VAD config needed.
- **BYO key** — `OPENAI_API_KEY` is required; validated at agent start.

## How It Works

1. The browser calls `/api/get_config`, which Next rewrites to the backend; the
   backend mints an Agora token from `AGORA_APP_ID` + `AGORA_APP_CERTIFICATE`.
2. The browser joins the RTC channel, then calls `/api/startAgent`; the backend
   validates `OPENAI_API_KEY` and starts an agent session using `OpenAIRealtime`.
3. The user speaks. Agora routes audio to the OpenAI Realtime endpoint.
4. OpenAI Realtime processes voice-to-voice and streams the response audio back.
5. The agent's voice plays in the channel. RTM transcript + metrics arrive in the web UI.
6. `/api/stopAgent` ends the session.

## Repo Map

- `web/` — Next.js frontend (:3000); RTC/RTM lifecycle and UI.
- `server/` — FastAPI agent backend (:8000); Agora tokens + agent lifecycle, OpenAI Realtime MLLM.
- `ARCHITECTURE.md` — system shape and component boundaries.
- `AGENTS.md` — guide for coding agents working in this repo.

## Troubleshooting

| Problem | Fix |
| --- | --- |
| `/startAgent` returns 400 | Check `OPENAI_API_KEY` is set and has OpenAI Realtime API access. |
| Agent starts but no audio | Ensure the model (`OPENAI_MODEL`) supports realtime voice. |
| Local calls fail under a global proxy (Clash, etc.) | Configure your proxy to send `127.0.0.1`, `localhost`, and RFC-1918 ranges DIRECT. |

## More Docs

- [ARCHITECTURE.md](https://github.com/AgoraIO-Conversational-AI/recipe-agent-realtime/blob/main/ARCHITECTURE.md)
- [AGENTS.md](https://github.com/AgoraIO-Conversational-AI/recipe-agent-realtime/blob/main/AGENTS.md)

## License

Released under the [MIT License](https://github.com/AgoraIO-Conversational-AI/recipe-agent-realtime/blob/main/LICENSE).