# File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.

from typing import Optional

from ..._models import BaseModel
from .beta_iterations_usage import BetaIterationsUsage
from .beta_server_tool_usage import BetaServerToolUsage
from .beta_fallback_credit_usage import BetaFallbackCreditUsage
from .beta_output_tokens_details import BetaOutputTokensDetails

__all__ = ["BetaMessageDeltaUsage"]


class BetaMessageDeltaUsage(BaseModel):
    cache_creation_input_tokens: Optional[int] = None
    """The cumulative number of input tokens used to create the cache entry."""

    cache_read_input_tokens: Optional[int] = None
    """The cumulative number of input tokens read from the cache."""

    fallback_credit: Optional[BetaFallbackCreditUsage] = None
    """Outcome of the `fallback_credit_token` presented on this request."""

    input_tokens: Optional[int] = None
    """The cumulative number of input tokens which were used."""

    iterations: Optional[BetaIterationsUsage] = None
    """Per-iteration token usage breakdown.

    Each entry represents one sampling iteration, with its own input/output token
    counts and cache statistics. This allows you to:

    - Determine which iterations exceeded long context thresholds (>=200k tokens)
    - Calculate the true context window size from the last iteration
    - Understand token accumulation across server-side tool use loops
    """

    output_tokens: int
    """The cumulative number of output tokens which were used."""

    output_tokens_details: Optional[BetaOutputTokensDetails] = None
    """Breakdown of output tokens by category.

    `output_tokens` remains the inclusive, authoritative total used for billing.
    This object provides a read-only decomposition for observability — for example,
    how many of the billed output tokens were spent on internal reasoning that may
    have been summarized before being returned to you.
    """

    server_tool_use: Optional[BetaServerToolUsage] = None
    """The number of server tool requests."""
