YuE2 bring-your-own ABC score vs Music Router prompt timestamps

The YuE2-3B card says you can compose with melody plus chords, melody only, or direct generation, and bring your own ABC score. Sume's Music Router has no score or notation field. You describe structure in the prompt, using timestamps such as [0:00-0:30] Intro: ..., and the model reports lyrics or a section map afterwards.

YuE2 facts are from the model card, read 2026-10-01. Sume facts are from Music Router, read 2026-10-01.

What does the YuE2 card say about scores?

The feature list says: "Compose and edit: melody + chords, melody-only, or direct generation; bring your own ABC score." A second bullet says an agent can turn musical feedback into score, style and lyric revisions, then let YuE2 render the next version. The card's demo follows one song through 9 steps and 14 versions.

How do I steer structure on Sume?

Put it in the positive prompt. The docs give two examples: "a 2-minute track" for length and [0:00-0:30] Intro: ... for sections, and say to put exclusions in the positive prompt because negative_prompt is unsupported when non-empty. The prompt limit is 1-5000 characters.

curl -X POST https://api.sume.com/v1/music-router/generate \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: music-router-001" \
  -d '{
    "model": "sume/music-auto",
    "prompt": "Warm lo-fi hip hop, 84 BPM, C minor. [0:00-0:10] Intro: Rhodes chords. [0:10-0:30] Verse: boom-bap drums, muted trumpet. Instrumental, no vocals."
  }'

Can I get an editable score out?

The cited Sume docs say result.lyrics carries the model-reported lyrics or section map when present. They do not describe returning ABC or any other score. To change a section, revise the prompt and submit a new job; see music for one section.

Which ids can the router run?

sume/music-auto is the default, plus lyria-3.5 and lyria-3-pro. Unknown ids fail with 400 model_not_found and a catalog_url.