Start a Seedance video generation task on BytePlus ModelArk and return its task ID. Generation is ASYNCHRONOUS and takes minutes: this tool returns immediately without a video. Follow it with seedance_wait_for_video (blocks until the video is ready - use this when the user just wants the video) or seedance_get_video (single status check).

Choose exactly ONE input shape; BytePlus rejects mixtures:

1. text-to-video: prompt only.

2. image-to-video: first_frame (+ optional last_frame) - the output starts (and ends) on those exact frames.

3. omni reference-to-video: image_references / video_references / audio_references - the model borrows subjects, style, motion or sound from them. Seedance 2.5 accepts up to 30 images, 10 videos and 10 audio clips, and can run on audio alone. Refer to them in the prompt as '@Image 1', '@Video 2' etc. first_frame/last_frame cannot be combined with the *_references parameters.

Media may be a local file path, a public https:// URL, or an asset://. Local images (jpeg, png, webp, bmp, tiff, gif, heic, heif; max 30 MB) and local audio (wav, mp3; max 15 MB) are inlined automatically. Local VIDEO files cannot be uploaded - BytePlus takes reference video only as a public URL, so host it first.

Seedance 2.5 supports resolution 480p/720p/1080p, ratio 16:9/4:3/1:1/3:4/9:16/21:9/adaptive, and duration 4-30 seconds (or -1 to let the model choose). It does NOT support seed or camera_fixed - describe camera moves in the prompt instead.

Check a Seedance generation task once and return its current state. Use this for a quick status poll; if the user is waiting for the finished video, use seedance_wait_for_video instead of calling this in a loop. Status is one of queued, running, succeeded, failed, cancelled, expired. On success the result carries video_url (valid 24 hours), plus the resolution, aspect ratio, duration and frame rate BytePlus actually produced. On failure it carries error_code and error_message. Task records are kept for 7 days.

Poll a Seedance task until it succeeds, fails, or the timeout elapses, then return the final result including the video URL. Call this right after seedance_create_video whenever the user wants the finished video rather than a task ID. Polling backs off automatically. A 5-10 second clip usually lands within a few minutes; long or 1080p jobs take longer, so raise timeout_seconds for those. A timeout does not cancel anything - the task keeps running and can be waited on again.

Save a finished Seedance video to a local file. Use this whenever the user wants to keep the video rather than just see a link: output URLs expire 24 hours after the task completes and allow only 100 downloads, and BytePlus cannot re-issue them. Pass the task_id - the tool looks up the current URL itself, so it works on any task that succeeded within the last 24 hours. The task must be in 'succeeded' state. Without output_path the file is written to the current directory as .mp4. An existing file is never overwritten unless overwrite is true. Set include_last_frame to also save the closing PNG, which is only available if the task was created with return_last_frame.

Cancel a Seedance task that is still queued, or delete the record of one that already finished. BytePlus maps both to a single DELETE call. Only queued tasks can actually be cancelled - a task already running cannot be stopped, and the call will fail. Cancelled tasks are purged after 24 hours.

List recent Seedance generation tasks for this account, newest first, optionally filtered by status or model. Useful to recover a task ID that was lost, to check what is still queued, or to re-fetch a video URL for a task that finished within the last 24 hours. BytePlus keeps task records for 7 days.