The omp speech device forwards a voice only when the call passes voice_id - there is no setting that feeds one (speech.voice is the TUI speak-aloud Kokoro enum, tts.localVoice belongs to the local backend) - so every harness voiceover arrives with no voice key and the shim answered 400 "unknown voice None". Measured on the deployed endpoint 2026-10-18, from a restarted session with the speech role pointed here.
DEFAULT_VOICE makes the absent case a spoken operator choice instead of a code surprise: the pack named there answers a voice-less request and the journal line is marked (default), so an unrequested voice never reads later like a requested one. An UNKNOWN name still 400s with the list that exists - the no-silent-fallback law that this endpoint was built on is untouched, and the strict shape stays the code default (empty DEFAULT_VOICE), which the second new seam test pins. Ships narrator1 in scripts/frank-tts.env.
Frank