Luma Agents failed generation refunds vs Sume's not-billed rule

Luma never charges synchronous errors, and refunds async failures with content_moderated, generation_failed or output_not_found; budget_exhausted may be partly charged. Sume's image rule is simpler: a generation is billed in full when it completes and not billed when it fails or is cancelled.

Luma facts are from its Pricing page; Sume facts are from Image models and Generation admission, read 2026-10-01.

Which Luma failures are refunded?

What does Sume do on failure?

The Image API doc says billing is all-or-nothing. Completed generations are fully billed at endpoint pricing; failed or cancelled generations are not billed, and failed requests return 502 Bad Gateway. A client that disconnects early is also billed as a failed generation, which means not at all.

The docs name no partial-charge case, so there is no table of failure codes to map.

When is nothing reserved at all on Sume?

Generation submit fails with 402 insufficient_credits before provider work starts, so a wallet that cannot cover the request never reaches the provider. The error table also lists 429 queue_full and 429 rate_limited as submit-time rejections.

How should I reconcile cost after failures?

On Luma, record the failure_code of each async failure and expect a refund for the three listed codes; check the dashboard charge for budget_exhausted. On Sume, sum the usage.cost of completed images only. For the video side of the same question, see do failed AI video jobs cost money.