---
tool_name: audio-mix
summary: Overlay background music under a voice track at 0–100% BGM volume — output stays exactly as long as the voice.
input:
  file: binary, required # 2+ audio files — first is the main voice track, the rest are BGM (max 200MB)
  bgm_volume: number, required, min 0, max 1 # BGM 音量（0–1）
output:
  preview_url: string | watermarked preview, free, no auth
  task_id: string | unique task identifier
  payment_url: string | end-user must complete one-time payment to unlock final output
  final_download_url: string | only available after successful payment
auth: login via email/phone OTP on https://audio-mix.yeezhan.com; API callers use a personal API key (Bearer yeek_...)
payment_rule: one-time charge $0.99 per task. NO credits, NO account balance. One payment unlocks only this task.
valid_window: 24 hours after payment
errors:
  - file_too_large
  - invalid_input
  - unsupported_type
  - target_unreachable
  - processing_failed
endpoint: https://audio-mix.yeezhan.com/api/v1/run
---