Lyria 3 Pro or Lyria 3.5 on Sume: pin the engine, pay $0.125

The Music Router docs list three routable ids: sume/music-auto (the default, which resolves to Lyria 3.5 today), lyria-3.5 and lyria-3-pro. Pinning an id sends your prompt to that engine; leaving model out means sume/music-auto. The docs state the pricing rule in one line: every Music Router model charges the fixed Music price per audio generation, and the catalog shows each model's provider list price for reference.

The fixed Music price is **$0.125** per accepted generation (read 2026-10-07 from Music 1.0 and the repo's catalog). It does not change with prompt length or with an optional image_url.

What changes when you pin

Because the price is flat, the choice is about sound and about repeatability. If you pin an engine, a rerun of the same brief reaches the same engine even after the router's default changes.

Request

The body takes prompt (1 to 5,000 characters) and optional image_url, and rejects duration and duration_seconds. Ask for length in the prompt, such as "a 2-minute track", or with section markers like [0:00-0:30] Intro: .... GET /v1/music-router/models returns the catalog.

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: pin-pro-001" \
  -d '{"model": "lyria-3-pro", "prompt": "Dry funk, 104 BPM, E minor. A 30-second track. Instrumental, no vocals."}'

Budgeting

At $0.125, eight tracks cost a dollar and a 12-version A/B of a bed is $1.50. Since the price does not depend on the engine, run the same brief on both ids and keep the one that sounds right; the second take costs the same 12.5 cents as the first.