Struct TokenUsage 

pub struct TokenUsage {
    pub input_tokens: u64,
    pub output_tokens: u64,
    pub total_tokens: u64,
    pub cache_creation_input_tokens: Option<u64>,
    pub cache_read_input_tokens: Option<u64>,
    pub cached_input_tokens: Option<u64>,
}

Token usage reported by a provider.

Fields

input_tokens: u64

Number of input tokens.

output_tokens: u64

Number of output tokens.

total_tokens: u64

Total token count.

cache_creation_input_tokens: Option<u64>

Number of input tokens written to cache by this call.

Populated by Anthropic when the request created a new cache entry. None for providers that do not report cache writes or when no caching occurred.

cache_read_input_tokens: Option<u64>

Number of input tokens served from cache by this call.

Populated by Anthropic (cache_read_input_tokens) and DeepSeek (prompt_cache_hit_tokens). None when the provider does not report cache reads or no cache was hit.

cached_input_tokens: Option<u64>

Number of input tokens served from cache by this call.

Populated by OpenAI’s prompt_tokens_details.cached_tokens. None for providers that do not report this field.

Implementations

impl TokenUsage

pub const fn new(input_tokens: u64, output_tokens: u64) -> Self

Creates token usage and computes the total.

Cache fields default to None; use TokenUsage::with_cache_stats to populate them or TokenUsage::merge to combine two usages.

pub const fn with_cache_stats( self, cache_creation_input_tokens: Option<u64>, cache_read_input_tokens: Option<u64>, cached_input_tokens: Option<u64>, ) -> Self

Returns a copy of this usage with the cache fields populated.

pub fn cache_tokens(&self) -> u64

Returns the total number of cache-related input tokens.

Sums cache_creation_input_tokens, cache_read_input_tokens, and cached_input_tokens when present. Returns 0 when no provider reported any cache stats.

pub fn merge(self, other: Self) -> Self

Merges two usages by summing all numeric fields.

Numeric fields (input_tokens, output_tokens, total_tokens) are summed. Cache fields use the rule: None + None = None, None + Some(x) = Some(x), Some(x) + None = Some(x), Some(x) + Some(y) = Some(x + y).

Trait Implementations

impl Clone for TokenUsage

fn clone(&self) -> TokenUsage

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TokenUsage

impl Debug for TokenUsage

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for TokenUsage

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for TokenUsage

impl PartialEq for TokenUsage

fn eq(&self, other: &TokenUsage) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for TokenUsage

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for TokenUsage