Knowledge > Integrations > Cartesia
Cartesia Integration
Note: As of March 2026, Cartesia no longer hosts the voice agent. The agent runs on LiveKit Cloud + Railway. Cartesia remains the TTS provider only — it supplies voice synthesis (Cartesia Sonic) during live calls via the
livekit-plugins-cartesiaplugin.
Cartesia provides TTS (text-to-speech) voice synthesis for ChurchWiseAI voice agent calls. The voice agent is a Python service built on the LiveKit Agents SDK, deployed to Railway. During calls, the agent uses livekit-plugins-cartesia to synthesize speech via Cartesia Sonic.
Account Info
| Field | Value |
|---|---|
| Account | churchwiseai |
| TTS Technology | Cartesia Sonic (via livekit-plugins-cartesia) |
| MCP tools | mcp__cartesia-mcp__text_to_speech, clone_voice, list_voices, etc. |
How Used Per Product
| Product | Purpose |
|---|---|
| ChurchWiseAI Voice Agent | TTS voice synthesis during calls — Cartesia Sonic voices speak agent responses |
| TTS (MCP) | Voice cloning and TTS generation for admin tools |
Key Environment Variables
| Variable | Scope | Used By |
|---|---|---|
CARTESIA_API_KEY | Voice agent runtime (Railway) | livekit-plugins-cartesia auth |
CARTESIA_FEMALE_VOICE_ID | Voice agent runtime (Railway) | TTS voice selection |
CARTESIA_MALE_VOICE_ID | Voice agent runtime (Railway) | TTS voice selection |
Additional LLM API keys are required in the voice agent environment:
- Google AI API key (Gemini 2.5 Flash — Coordinator agent)
- Anthropic API key (Claude Haiku 4.5 — Care agent)
SUPABASE_URLandSUPABASE_SERVICE_ROLE_KEY(Python env vars, no NEXT_PUBLIC_ prefix)
Cost Model / Usage Limits
- Cartesia charges per-minute of TTS usage during voice calls.
- This is why Voice and Bundle plans are monthly-only (no annual billing) — costs scale with usage.
- MCP TTS tool usage (for voice cloning, admin tools) is billed separately per request.
Failure Modes & Recovery
| Failure | Symptom | Recovery |
|---|---|---|
| Cartesia API key invalid | TTS synthesis fails, calls connect but agent is silent | Verify CARTESIA_API_KEY in Railway environment variables |
| Voice ID not found | TTS uses fallback voice or fails | Check CARTESIA_FEMALE_VOICE_ID / CARTESIA_MALE_VOICE_ID against Cartesia dashboard |
| Supabase unavailable | Voice agent falls back to Sales Agent (non-fatal by design) | All Supabase calls are try/except with fallback. Calls still connect. |
See Also
- LiveKit Integration — the voice agent platform (SIP gateway + session management)
- Twilio — provides the phone numbers that route calls to LiveKit
- Supabase — voice agent reads church config and writes call data here
- Vercel — hosts the
/api/admin/provision-numberendpoint used for new church setup C:\dev\CLAUDE.md— multi-agent git safety, voice agent architecture overview