server/tts/cartesia_tts.py wraps the raw Cartesia Sonic WebSocket API
(wss://api.cartesia.ai/tts/websocket) — streaming PCM s16le, one voice
(CARTESIA_VOICE_ID, D-006). server/tts/piper_tts.py wraps piper-tts
self-hosted synthesis (R4 mitigation, open-weights). Both implement
TTSProvider (synthesize streaming + synthesize_all). Both degrade
gracefully (no audio, no crash) when the API key / voice model is absent.
PRAXIS_TTS=cartesia|piper selects the adapter via the registry with no
pipeline change (D-014). 7 unit tests pass (mock streams + env selection
+ graceful missing-key/model handling).
---ci---
phase: 1
milestone: v0.1
plan: 02
task: 02-02
status: execute
persona: backend-engineer
requirements:
covered: [REQ-VOICE-02]
---/ci---
Praxis CI
f0afc8ef57