Struct Usage 

#[non_exhaustive]
pub struct Usage {
    pub input_tokens: u32,
    pub output_tokens: u32,
    pub cached_input_tokens: u32,
    pub cache_creation_input_tokens: u32,
    pub cache_creation_5m_tokens: u32,
    pub cache_creation_1h_tokens: u32,
}

Token counters reported by the provider for a turn.

Aggregated to the run level by the engine and surfaced on StreamChunk::RunFinished / StreamChunk::TurnFinished. Fields not surfaced by a given provider stay at 0.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

input_tokens: u32

Total prompt tokens charged this turn (cached + uncached).

output_tokens: u32

Tokens generated by the model this turn.

cached_input_tokens: u32

Subset of input_tokens that were served from prompt cache rather than recomputed. Zero when the provider does not support prompt caching or when this turn missed the cache.

cache_creation_input_tokens: u32

Total tokens written to a cache during this turn. When the provider reports a TTL breakdown (Anthropic), this equals the sum of Self::cache_creation_5m_tokens + Self::cache_creation_1h_tokens. When only the legacy flat field is reported, the breakdown stays at zero and only this total is populated.

cache_creation_5m_tokens: u32

Cache writes with a 5-minute TTL (Anthropic ephemeral default). Zero when the provider does not surface a TTL breakdown.

cache_creation_1h_tokens: u32

Cache writes with a 1-hour TTL (Anthropic explicit ttl=“1h”). Zero when the provider does not surface a TTL breakdown.

Trait Implementations

impl Add for Usage

type Output = Usage

The resulting type after applying the + operator.

fn add(self, other: Usage) -> Usage

Performs the + operation.

impl AddAssign for Usage

fn add_assign(&mut self, other: Usage)

Performs the += operation.

impl Clone for Usage

fn clone(&self) -> Usage

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Usage

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Usage

fn default() -> Usage

Returns the “default value” for a type.

impl Copy for Usage