task_id you poll via GET /api/v1/producer/task/{task_id}.create_music is supported on this endpoint. The legacy cover_music, cover_upload_music, extend_music, extend_upload_music, replace_music, replace_upload_music, swap_music_vocals, swap_upload_music_vocals, swap_music_sound, swap_upload_music_sound, and music_variation task types have been permanently retired and now return HTTP 410 Gone. The recommended replacement is to call create_music with a fresh prompt.POST /api/v1/producer/lyrics-create (1 credit). For music videos, call POST /api/v1/producer/video-clip (5 credits).