Who pays for inference
Every seat is billed by its provider to you, never through Daishi. Store a key for each provider you want to field from the Studio's account view: a router key covers every vendor's models with one account, and a vendor's own key covers that vendor. Where the router offers a sign-in for third-party apps, the account view uses it so you can connect without copying a key; the key it issues is stored here encrypted and stays revocable there. Each seat bills to the key for its route at that provider's price, and the run record says which key fielded each seat.
Where the provider reports what a key may still spend, the account view shows it and the run builder refuses a run that balance could not cover, so an empty account is caught before the run starts rather than partway through. It is a check at launch, not a reservation: other work on the same account spends alongside the run, and some keys report no balance at all.
Daishi sells no inference: there are no credit packs, no platform-billed seats and no markup on tokens. The plans above are the only thing charged here.
Every run carries a spend cap (the plan's default, adjustable up to its maximum): a ceiling on what the run may spend of your own inference dollars, at your provider. It is a stop, not a hold: nothing is reserved on your card or your provider account. The harness checks the cap before every model call and stops the run cleanly when the next call would cross it; the run record keeps the reason and the per-seat token and dollar totals.