WatchBuddy

A standalone Apple Watch voice assistant. Tap the mic, ask a question, and hear the AI respond — all from your wrist.

Architecture

The watch app supports two modes:

Trusted Mode (Server does everything)

A single round trip. The watch sends audio to the server, which handles STT → LLM → TTS and returns MP3 audio. The server uses its own API key. Users authenticate with a shared access key set in the server's .env file.

Watch --[audio + access key]--> Server (STT → LLM → TTS) --[mp3]--> Watch

BYOK Mode (Bring Your Own Key)

Three round trips. The user's API key never touches the server — it goes directly from the watch to the LLM provider.

Watch --[audio]--> Server (STT) --[text]--> Watch
Watch --[text + API key]--> LLM Provider --[text]--> Watch
Watch --[text]--> Server (TTS) --[mp3]--> Watch

Supported LLM providers in BYOK mode: Gemini, OpenAI, Anthropic.

Project Structure

WatchAI/                          # iOS companion app (required wrapper for App Store)
  WatchAIApp.swift                # App entry point
  ContentView.swift               # Placeholder UI directing users to the watch

WatchAIWatch Watch App/           # Standalone watchOS app
  WatchAIWatchApp.swift           # App entry point
  ContentView.swift               # Main UI — mic, stop, play buttons
  SettingsView.swift              # Server URL, mode toggle, provider picker, API key
  Managers/
    NetworkManager.swift          # Dual-path networking (trusted vs BYOK)
    AudioRecorderManager.swift    # M4A recording via AVAudioRecorder
    AudioPlayerManager.swift      # MP3 playback via AVPlayer
    SessionManager.swift          # WKExtendedRuntimeSession for background audio
    KeychainManager.swift         # Secure API key storage

docs/                             # GitHub Pages
  index.html                      # Support page
  privacy.html                    # Privacy policy

Server

The companion server lives in a separate directory. See Server/README or set up your own with these endpoints:

Endpoint	Method	Description
POST /v1/chat	multipart	Full pipeline (trusted mode). Requires api_key form field. Returns MP3.
POST /v1/stt	multipart	Speech-to-text only. Returns {"text": "..."}.
POST /v1/tts	JSON	Text-to-speech only. Accepts {"text": "..."}. Returns MP3.
GET /health	—	Health check.

Setup

1. Open WatchAI.xcodeproj in Xcode
2. Set your team and bundle identifiers
3. Build and run the WatchAIWatch Watch App scheme on your Apple Watch
4. In the watch app, tap the gear icon to configure:
   • Server URL: Your server's address (e.g., https://myserver.example.com)
   • Mode: Toggle "Use Server's AI" for trusted mode, or leave off for BYOK
   • API Key: Paste your access key (trusted mode) or LLM API key (BYOK mode)

Requirements

• Xcode 26+
• watchOS 26+
• A running server instance with STT/TTS capabilities