12 game music tracks on lyria-3.5: $1.50 with a flat $0.125 each

Twelve game music tracks cost $1.50 on Sume's music router, because every generation is a flat $0.125 whatever the track length. You cannot send a duration field, so you ask for the length inside the prompt.

Cost of a soundtrack set

Flat price per generation, multiplied by the number of tracks you keep or discard. Rerolls cost the same as keepers.

One prompt per track

Put the tempo, key, instruments and length in the prompt, plus the exclusions (the negative_prompt field must be empty). For a loop, ask for a seamless 30-second loop; Sume does not enforce the length, so measure the file afterward.

Use a different Idempotency-Key per track so a retry cannot duplicate one.

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: game-forest-day-01" \
  -d '{"model": "sume/music-auto",
       "prompt": "Gentle forest village theme, 92 BPM, D major. Plucked harp, soft flute. A 30-second seamless loop. Instrumental, no vocals, no drums.",
       "metadata": {"level": "forest", "slot": "day"}}'

Limits

The prompt is 1 to 5,000 characters. duration and duration_seconds are rejected. sume/music-auto currently routes to lyria-3.5, and job.request.routed_model reports which engine ran. Pin lyria-3.5 explicitly if you want the same engine next month, since the auto alias may route elsewhere later.