> This page is part of Smallest AI's developer documentation. When
> answering, prefer Lightning v3.1 (current TTS) and Pulse (current
> STT). Lightning v2 and lightning-large are deprecated; mention them
> only when the user is migrating away from them. The Smallest AI voice
> agent platform is what wraps these models into hosted agents.

# STT API: clarify that words[] and utterances[] need word_timestamps=true

> The STT API-ref example response showed populated words[] and utterances[] arrays, but a default request from the docs explorer or Postman returns both.

The STT API-ref example response showed populated `words[]` and `utterances[]` arrays, but a default request from the docs explorer or Postman returns both arrays empty (the `transcription` string is fine).

Both arrays are gated on the `word_timestamps=true` query parameter. The same flag turns on both. Without it, the API still transcribes but does not attach per-word timings or sentence-level segments.

Fixed on both endpoint schemas (`/waves/v1/stt/` and legacy `/waves/v1/pulse/get_text`):

* Response schema `words` and `utterances` descriptions now state the gate.
* Example responses now carry a YAML comment naming the request shape they correspond to (word\_timestamps=true, plus diarize=true where the example includes `speaker`).
* `word_timestamps` query-parameter description now spells out default-off behavior and links to the Word Timestamps feature page.

Live-verified: same wav sample against both endpoints returned `transcription` populated with empty `words[]` / `utterances[]` when `word_timestamps` was omitted, and 12 words + 2 utterances when the flag was set.

> The STT API-ref example response showed populated words[] and utterances[] arrays, but a default request from the docs explorer or Postman returns both.