# tinker.types.SamplingPrefillBillingEvent

## *class* [**tinker.types.SamplingPrefillBillingEvent**](https://github.com/thinking-machines-lab/tinker/blob/main/src/tinker/types/billing_usage_response.py#L31)(*[StrictBase](https://github.com/thinking-machines-lab/tinker/blob/main/src/tinker/_models.py#L76)*)

Prompt (prefill) tokens processed while sampling.

**Fields:**

- [**type**](https://github.com/thinking-machines-lab/tinker/blob/main/src/tinker/types/billing_usage_response.py#L34) (*Literal['sampling_prefill']*)
- [**cached**](https://github.com/thinking-machines-lab/tinker/blob/main/src/tinker/types/billing_usage_response.py#L36) (*bool*) – True when the tokens were served from the prefill cache (billed at the discounted cached rate); False for full-rate prefill
- [**token_count**](https://github.com/thinking-machines-lab/tinker/blob/main/src/tinker/types/billing_usage_response.py#L40) (*int*) – Prefill token count for the bucket