Operations and limits
The reviewed models are
veo_3_1 and veo_3_1-fast in Discounted-Gemini-2. Check current availability in Model Square.
Image, reference-video, mode and audio controls are outside this reviewed contract.
Submit
Poll and download
SetTASK_ID to the returned id. Poll until completed or failed; pending states are queued and in_progress.
Errors and billing
Veo uses a completed-request price for this group. Follow-ups retain the original group and price. Failed tasks release their reservation; missing final usage can leave settlement pending. For400, check seconds, size and required fields. Unfinished downloads return 400; expired results return 410. Keep the task ID after a timeout or submission_uncertain rather than submitting again. See shared video errors.