Route LLMFullResponseEndFrame through the serialization queue instead
of pushing it directly downstream when push_text_frames is enabled.
This ensures the frame is emitted only after the audio context is
fully drained, preserving correct ordering relative to TTSTextFrames.
Previously, the final sentence TTSTextFrame would arrive at the
LLMAssistantAggregator after LLMFullResponseEndFrame, causing it to
be dropped from the conversation context (especially with RTVI text
input where no subsequent interruption would flush the orphaned text).
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.
