Enum TokenSource 

pub enum TokenSource {
    Estimated,
    Provided,
    Definite,
}

How a token count was obtained.

When a session mixes sources (e.g. some calls estimated, some provided), the aggregate source degrades to the weakest (least precise) variant via TokenSource::weaker.

Variants

Estimated

Character-based heuristic (ASCII ~4c/t, CJK ~1.5c/t). ±30% accuracy.

Provided

Reported by the host (e.g. MCP Sampling usage metadata). Accuracy depends on the host’s tokenizer.

Definite

Exact count from a known tokenizer (e.g. local BPE).

Implementations

impl TokenSource

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

Return the weaker (less precise) of two sources.

Used when accumulating across multiple LLM calls in a session. If any call is Estimated, the aggregate is Estimated.

Trait Implementations

impl Clone for TokenSource

fn clone(&self) -> TokenSource

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TokenSource

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for TokenSource

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for TokenSource

fn eq(&self, other: &TokenSource) -> 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 TokenSource

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for TokenSource

impl Eq for TokenSource

impl StructuralPartialEq for TokenSource