Where are the lyrics in a Lyria 3.5 result? Gemini vs Sume

On Google's Gemini API the Lyria 3.5 model page lists its outputs as audio (MP3) and text (lyrics), and the music guide says you read the song's lyrics and structure from interaction.output_text. On Sume the same information, when the engine provides it, is in result.lyrics on the finished job, next to the audio artifact in result.artifacts[]. The Music Router docs say result.lyrics carries the model-reported lyrics or section map when present.

What does Google say you get back?

From the Lyria 3.5 model page: input is text and image, output is audio (MP3) and text (lyrics), and the input token limit is 131,072. From the music generation guide: output_audio returns the last audio block and output_text returns lyrics and structure, with a note that for interleaved responses you may need to iterate over the steps yourself.

Can I trust result.lyrics as a timing map?

No. The Music 1.0 docs say provider lyrics may describe tempo and structure but that this is model-reported metadata, not an audio measurement. If you need to cut at a section boundary, find the boundary in the audio. For lyric captions, the stored guide Lyric video captions for an AI song shows the script_text route.

How do I know whether an engine returns lyrics?

Ask the catalog: GET /v1/music-router/models rows include capabilities with text_to_music, image_conditioning, lyrics and max_prompt_characters. Check the lyrics flag for the id you plan to pin; with sume/music-auto, read the field on the result and handle its absence.