Two claims in this stack's docs were reasoned from the wrong hop, and one of
them hid a dead feature since deploy. Re-measured from esh-docker-vm against
the live .env:
1. "An unknown `model` routes to the gateway default" — true of :8198, false of
the path Lobe takes. LiteLLM resolves the model name first, so Lobe's default
`tts-1` returns 403 (`key not allowed to access model`) and never reaches the
gateway. `ext-tts` returns 200 + audio. The endpoint inheriting
OPENAI_PROXY_URL is necessary but not sufficient: Settings -> TTS -> OpenAI
TTS model -> `ext-tts` is a required one-time step per browser, and removing
it needs a LiteLLM alias plus a key allow-list entry (both master-key, so
infra-ops).
2. "`response_format: mp3` ... set it in the UI" — not possible. Lobe's OpenAI
TTS client sends `{input, model, voice}` and nothing else (server bundle
chunks/29685.js), so format is not selectable from this stack at any level.
The deploy gets the fleet gateway's default (WAV, ~23.5 MB for a 245 s turn),
relabelled `audio/mpeg` by LiteLLM. That is tts-dev's fence, not this one's.
Comment/doc only — no functional change, so the host copy needs no redeploy.
vh
ca8c0a318e