What causes "Unexpected error during speech-to-text" in home-assistant/core?

Check the Home Assistant log for the 'Unexpected error during speech-to-text' traceback — the chained source exception names the real failure.

home-assistant/core · error · SpeechToTextError

stt-stream-failed

stt-stream-failed

Error message

Unexpected error during speech-to-text

What it means

SpeechToTextError with code stt-stream-failed wraps any unexpected exception thrown while streaming audio to the STT provider (async_process_audio_stream or the internal _speech_to_text_stream generator). The original traceback is logged via _LOGGER.exception before rethrowing, so the underlying cause is visible in the logs but hidden behind this generic pipeline error.

Source

Thrown at homeassistant/components/assist_pipeline/pipeline.py:972

            ):
                stt_vad = VoiceCommandSegmenter(
                    silence_seconds=self.audio_settings.silence_seconds
                )

            result = await self.stt_provider.async_process_audio_stream(
                metadata,
                self._speech_to_text_stream(audio_stream=stream, stt_vad=stt_vad),
            )
        except asyncio.CancelledError, TimeoutError:
            raise  # expected
        except hass_nabucasa.auth.Unauthenticated as src_error:
            raise SpeechToTextError(
                code="cloud-auth-failed",
                message="Home Assistant Cloud authentication failed",
            ) from src_error
        except Exception as src_error:
            _LOGGER.exception("Unexpected error during speech-to-text")
            raise SpeechToTextError(
                code="stt-stream-failed",
                message="Unexpected error during speech-to-text",
            ) from src_error

        _LOGGER.debug("speech-to-text result %s", result)

        if result.result != stt.SpeechResultState.SUCCESS:
            raise SpeechToTextError(
                code="stt-stream-failed",
                message="speech-to-text failed",
            )

        if not result.text:
            raise SpeechToTextError(
                code="stt-no-text-recognized", message="No text recognized"
            )

        self.process_event(

View on GitHub (pinned to 58a3fdb3ea)

Solutions

Check the Home Assistant log for the 'Unexpected error during speech-to-text' traceback — the chained source exception names the real failure.
Restart the STT backend (e.g. Wyoming Whisper add-on) and confirm it stays healthy during a request.
If the traceback points at audio handling, verify the stream yields chunks in the announced format until a clean end-of-stream.
For recurring provider crashes, inspect the provider's own logs (add-on logs) for OOM or model-load errors.

Defensive patterns

Strategy: retry

Try / catch

from homeassistant.components.assist_pipeline.error import SpeechToTextError
try:
    await pipeline_job.run()
except SpeechToTextError as err:
    if err.code == "stt-stream-failed":
        _LOGGER.error("STT failed: %s", err.__cause__)  # original traceback is in logs
        # optionally retry once after provider restart
        ...

Prevention

Watch STT backend (add-on/container) health and restart it on crash loops.
Always log err.__cause__ context; the real failure is the chained exception.
Keep Whisper models within the host's memory budget.

When it happens

Trigger: Any non-auth, non-timeout exception during STT: the Wyoming connection drops mid-stream, the provider process crashes, a malformed audio chunk breaks the stream generator, or a custom provider raises a bug.

Common situations: Whisper add-on/container running out of memory or restarting mid-request, network interruption to a remote STT service, bugs in custom stt provider integrations, or audio streams that end prematurely.

Related errors

AI-assisted analysis of home-assistant/core@58a3fdb3ea (2026-08-14). Data as JSON: /api/errors/246ff8432034270c. Report an issue: GitHub.