When an interruption arrives before any LLM text reaches run_tts, the
turn context ID exists but was never registered via create_audio_context.
Calling flush_audio for this unregistered context sends a message to the
provider (e.g. ElevenLabs) with a context_id it has never seen, which
implicitly creates a server-side context that is never closed. After
enough rapid interruptions these phantom contexts accumulate and exceed
the providers limit (ElevenLabs: 5 simultaneous contexts, 1008 policy
violation).
Guard the flush call with audio_context_available so it only fires when
the context was actually opened.
Fixes#4114
- Route audio through audio contexts (append_to_audio_context) instead of
pushing frames directly, enabling proper turn management and interruptions
- Add push_stop_frames and push_start_frame so the base class handles
TTSStartedFrame/TTSStoppedFrame lifecycle
- Remove manual context_id tracking (self._context_id) in favor of
get_active_audio_context_id()
- Don't call remove_audio_context on "complete" — Smallest sends one
per request, not per turn; let the base class timeout handle cleanup
- Guard v2-only params (consistency, similarity, enhancement) so they
aren't sent to lightning-v3.1
- Remove request_id from request payload (not a documented request field)
- Add flush_audio override to send flush to WebSocket
Adds SmallestTTSService, a WebSocket-based TTS service using Smallest AI's
Lightning v3.1 model. Follows current Pipecat service conventions:
- SmallestTTSSettings dataclass with runtime-updatable settings (voice,
language, speed, etc.)
- Reconnects on model change; keepalive every 30s to prevent idle timeout
- TTS settings default to None so the API applies its own defaults
- Model enum: SmallestTTSModel.LIGHTNING_V3_1
Includes a foundational example (07zl-interruptible-smallest.py) using
Deepgram STT + Smallest TTS + OpenAI LLM.
STT integration will follow in a separate PR once the hallucination/finalize
behaviour is resolved.
Made-with: Cursor
Gets Gemini 3 support to the point where it works with:
- The "legacy" pattern from the previous (removed) 26- example
- inference_on_context_initialization=True (the default)
- inference_on_context_initialization=False
Add `domain` field to AssemblyAISTTSettings to support AssemblyAI's
streaming API `domain` query parameter, enabling specialized recognition
modes like Medical Mode (`medical-v1`).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Add warnings in SpeechTimeoutUserTurnStopStrategy and
TurnAnalyzerUserTurnStopStrategy when stop_secs differs from the
recommended default (0.2s) or when stop_secs >= STT p99 latency,
which collapses the STT wait timeout to 0s. Document the stop_secs=0.2
assumption in stt_latency.py.
