uttero
Uttero is a voice channel that lets Claude Code take and make phone calls during a coding session. An incoming call arrives as a channel not
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About
Uttero is a voice channel that lets Claude Code take and make phone calls during a coding session. An incoming call arrives as a channel notification; Claude hears the caller's transcription, speaks back via TTS through the `reply` tool, and keeps editing your codebase between turns. Works like a live collaborator who happens to be on a phone line. Tools exposed: reply (speak), call_user (outbound), end_call, list_calls. Audio, transcription, and TTS are handled by Uttero's hosted backend (api.uttero.dev). The plugin itself is ~500 lines of TypeScript that speaks MCP stdio and authenticated HTTPS. Credentials are stored locally at ~/.uttero/credentials.json (mode 600) and never shared with callers. The plugin deliberately omits `capabilities.experimental['claude/channel/permission']` so voice callers cannot approve Bash/Write/Edit tool use.
Details
- Kind
- Plugins
- Topic
- AI, RAG & memory
- Publisher
- utterodev
- Origin
- marketplace
- Category
- ferramentas
- Last push
- 2026-04-28T15:52:19Z
- Repository state
- ativo
- Language
- TypeScript
- License
- MIT
- Added
- 2026-08-30 01:48:58
- Updated
- 2026-08-30 01:48:58
- Origin id
utterodev/uttero-plugins/uttero
README
# Uttero
**Voice channel for Claude Code.** Receive phone calls while coding and let Claude answer in your voice. Uttero turns any Claude Code session into a live agent that can pick up a call, hear the caller, speak back via TTS, and keep working on your codebase between turns.
> Status: public preview. Requires Claude Code v2.1.80+ with `--dangerously-load-development-channels` while under review for the official marketplace allowlist.
## Demo
## Quick start
```bash
# Inside Claude Code — one-time setup
/plugin marketplace add utterodev/uttero-plugins
/plugin install uttero@uttero-plugins
/uttero:configure # paste the pair code from app.uttero.dev/settings/devices
# Start Claude Code with the voice channel enabled
claude --dangerously-load-development-channels server:uttero
```
After approval to the official marketplace the last line simplifies to `claude --channels plugin:uttero@uttero-plugins`.
## How it works
```mermaid
flowchart LR
caller["Caller<br/>(browser or mobile app)"]
api["api.uttero.dev<br/>STT · TTS · call routing"]
bridge["uttero bridge<br/>(MCP server)"]
claude["Claude Code session"]
caller <-- "WebRTC audio" --> api
api -- "SSE (bearer auth)" --> bridge
bridge -- "authenticated HTTPS" --> api
bridge <-- "stdio / channel events" --> claude
subgraph local["Your machine"]
bridge
claude
end
```
1. A caller hits your public URL (`app.uttero.dev/call/<id>`) or initiates a call from the mobile client.
2. Audio is streamed to `api.uttero.dev`, transcribed, and the transcription is pushed to your registered agent over an authenticated SSE stream.
3. The local bridge (this plugin) receives the transcription and forwards it into Claude Code as a `<channel source="ottrvoice" ...>` notification.
4. Claude responds via the plugin's `reply` tool; the text is sent back to `api.uttero.dev`, synthesized, and streamed back to the caller.
Everything between Claude and the caller traverses Uttero's hosted backend. The plugin itself is ~500 lines of TypeScript that speaks MCP stdio and authenticated HTTPS.
## Pairing
1. Sign in at <https://app.uttero.dev> (Google OAuth).
2. Open **Settings → Devices** and generate a pair code (format `XXXX-XXXX`, expires in 5 minutes).
3. In Claude Code, run `/uttero:configure` and paste the code when prompted. The command shells out to `bin/login.ts --code=<code>`.
4. The bridge now has an OAuth-derived bearer token stored at `~/.uttero/credentials.json` (file mode 600, refreshed automatically).
Revoke a device at any time from `app.uttero.dev/settings/devices`, or delete the local file with `rm ~/.uttero/credentials.json`.
## Security
See [SECURITY.md](./SECURITY.md) for the full threat model and vulnerability disclosure policy.
Key points for reviewers:
- **Inbound sender gating is server-side.** The bridge authenticates to `api.uttero.dev` with a rotating bearer token and trusts the authenticated SSE streams it receives. The service enforces which accounts can reach you. Per-caller allowlist management on your device is planned but not yet enforced (see `plugin/commands/access.md`).
- **No permission relay.** `capabilities.experimental['claude/channel/permission']` is deliberately omitted so voice callers cannot approve Bash/Write/Edit tool use.
- **Transcription content is untrusted.** Claude Code automatically wraps channel content in a system reminder instructing the model to treat the payload as untrusted data, not instructions. The plugin does not add any path for a caller to override that framing.
- **Credentials never leave the machine** except to `api.uttero.dev` for token refresh. The credentials file is mode 600.
## Privacy
See [PRIVACY.md](./PRIVACY.md). In short: audio, transcriptions, and call metadata flow through Uttero's hosted backend; transcriptions enter your Claude Code session context. Full policy at <https://uttero.dev/privacy>.
## Configuration
| Env var | Default | Purpose |
| :---------------- | :------------------------- | :------------------------------------------------------------------------------------- |
| `UTTERO_API_URL` | `https://api.uttero.dev` | Backend base URL. Override only for development against a local Uttero server. |
| `UTTERO_APP_URL` | `https://app.uttero.dev` | Frontend base URL (used to build sharable call links). |
Credentials live in `~/.uttero/credentials.json`. The file stores the refresh token, the last-known server URL, and metadata about the paired device.
## Tools exposed to Claude
| Tool | Purpose |
| :------------ | :------------------------------------------------------------------- |
| `reply` | Speak back into an active call via TTS. |
| `call_user` | Place an outbound call to a registered user. |
| `end_call` | Hang up an active call. |
| `list_calls` | List active calls on this agent. |
## Build & reproducibility
The published plugin ships a pre-built `dist/bridge.js` so the MCP runtime can launch the bridge with plain `node` (no Bun required on the user's machine). To rebuild from source and verify the shipped artifact:
```bash
cd plugin
bun install
bun run build
# outputs dist/bridge.js from bin/bridge.ts
```
Source of truth is `plugin/bin/bridge.ts`. Auth and credential helpers live in `plugin/bin/lib/`. The build command is a single `bun build --target node` — no bundler config, no custom transforms.
## Repository layout
```
.
├── .claude-plugin/
│ └── marketplace.json # catalog for the marketplace
├── plugin/ # Claude Code plugin (source of truth)
│ ├── .claude-plugin/
│ │ └── plugin.json
│ ├── bin/ # bridge.ts, login.ts, setup-mcp.ts
│ ├── commands/ # /uttero:configure, /uttero:setup, /uttero:access
│ ├── dist/ # built bridge.js
│ └── package.json
├── LICENSE # MIT
├── PRIVACY.md
├── README.md
└── SECURITY.md
```
## Links
- Website: <https://uttero.dev>
- App: <https://app.uttero.dev>
- Channels reference: <https://code.claude.com/docs/en/channels-reference>
## License
MIT — see [LICENSE](./LICENSE).