COS Glasses Server

Self-hosted AI heads-up display for Even G2 smart glasses. Runs on your Mac, talks to your local Claude Code CLI, and pushes answers, voice transcription, and notes to the lens. Your data never leaves your machine, and no API key is pasted into the phone for chat.

Quick start

npx @gotcos/glasses-server

The launcher checks Node, finds your CLI, downloads the local voice model, writes ~/.cos-glasses/.env, and starts the server on 0.0.0.0:3141. On boot it prints an API token — paste that into the COS Glasses app.

Requirements

• Node.js 20.11+ — https://nodejs.org
• Claude Code CLI (Opus/Sonnet/Haiku) — https://claude.ai/download, then claude login or Codex CLI (Codex High) — https://developers.openai.com/codex/, then codex login
• Even G2 glasses + the COS Glasses app from the Even Hub
• Optional: brew install whisper-cpp for free local voice (otherwise OpenAI API)
• Optional: Tailscale so your phone reaches your Mac from anywhere

No ANTHROPIC_API_KEY is needed — chat runs through your installed CLI, billed to your existing Claude or Codex subscription. Pick either per query, or set a default with COS_G2_DEFAULT_MODEL (opus|sonnet|haiku|codex-high). Codex runs sandboxed read-only by default (COS_CODEX_SANDBOX to adjust).

Connect your phone (the one gotcha)

The glasses app runs on your iPhone and must reach this server on your Mac.

1. The launcher binds 0.0.0.0 (all interfaces) for you.
2. Same WiFi (simplest): find your Mac's LAN IP (System Settings > Wi-Fi > Details), and in the COS Glasses app enter http://192.168.x.x:3141.
3. From anywhere: install Tailscale on the Mac + iPhone (same account), note the Mac's 100.x address, and enter http://100.x.x.x:3141.
4. Either way, paste the API token the server printed at boot.

To restrict the server to localhost only, set BIND_HOST=127.0.0.1 in ~/.cos-glasses/.env. The built-in IP allowlist blocks public-internet traffic regardless.

What it does

• Ask anything, get a streamed answer on the lens (/api/query, /v1/chat/completions)
• Live voice capture + transcription during meetings
• Local whisper.cpp transcription (free) with OpenAI fallback (optional)
• Tasks / calendar / people context if you run the COS Starter Kit (COS_SCRIPTS_DIR); otherwise it is glasses + AI only

Configuration

Config lives at ~/.cos-glasses/.env (created on first run). Every key is optional except an installed CLI. Highlights: BIND_HOST, PORT, COS_API_TOKEN (auto if unset), OPENAI_API_KEY (cloud voice fallback), COS_SCRIPTS_DIR (full pipeline). Your name + transcription vocabulary live in ~/.cos-glasses/.cos-profile.json (see .cos-profile.example.json).

Run from source

git clone https://github.com/ukaoma/cos-glasses-server.git
cd cos-glasses-server
npm install
BIND_HOST=0.0.0.0 npm run start:server

Troubleshooting

• Phone can't connect — check BIND_HOST=0.0.0.0, the same Tailscale account on both devices, and the correct 100.x IP + token.
• AI queries fail — run claude --version / codex --version, then claude login / codex login.
• Voice getting billed? — install whisper-cpp for free local transcription.

License

MIT. Learn more at gotcos.com.