Struct Usage 

pub struct Usage {
    pub input_tokens: u64,
    pub output_tokens: u64,
    pub cache_creation_input_tokens: u64,
    pub cache_read_input_tokens: u64,
}

Token-usage breakdown. Names match Anthropic’s API field names so the mapping stays obvious; OpenAI’s prompt_tokens / completion_tokens will fan into input_tokens / output_tokens when that adapter lands.

Verifying cache hits: if cache_read_input_tokens is zero across repeated ask() calls with the same schema, something in the prefix is invalidating the cache (a silent invalidator — datetime.now() in a system block, varying tool list, etc.).

Fields

input_tokens: u64

output_tokens: u64

cache_creation_input_tokens: u64

cache_read_input_tokens: u64

Trait Implementations

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<(), Error>

Formats the value using the given formatter.

impl Default for Usage

fn default() -> Usage

Returns the “default value” for a type.