ringback
Your AI agent can call your phone — and actually talk to you.
ringback gives an LLM (Claude, or any MCP client) tools to reach you on your phone — from a one-way "fierce" alert all the way to a live, interruptible voice conversation — using only free, self-hosted pieces. No paid telephony. No extra API key for the conversation: the model already driving the MCP is the voice on the line.
Highlights
- 📞 Two-way voice calls — the agent rings your phone, you talk, it transcribes you and replies in speech. Barge-in: talk over it and it stops.
- 🔔 Tiered alerts — a loud push (ntfy / Pushover) or a real SIP ring + chat message, fired only when the LLM judges it urgent.
- 🆓 Free & self-hosted — pjsua2 + whisper.cpp + Piper neural TTS + a free Linphone SIP account. No Twilio, no per-minute fees.
- 🧠 No conversation API key — the calling model is the brain; these tools are just its ears and mouth.
It ships two MCP servers, ringback-alert and ringback-voice:
Platform: macOS, Linux, and Windows (via WSL2 or Docker). TTS is Piper by default (same voice everywhere), falling back to the OS-native voice (
sayon macOS). The engine is headless — it never opens a local mic/speaker (all audio is WAV ↔ SIP/RTP), so no sound card is required. Setup guides: macOS · Linux · Windows · Docker.
