Struct ContextTracker 

pub struct ContextTracker { /* private fields */ }

Tracks context size using real token counts from provider responses combined with estimates for messages added after the last response.

This gives more accurate context size tracking than pure estimation, since providers report actual token counts in their usage data.

Example

use phi_core::context::ContextTracker;
use phi_core::types::Usage;

let mut tracker = ContextTracker::new();
// After receiving an assistant response with usage data:
tracker.record_usage(&Usage { input: 1500, output: 200, ..Default::default() }, 3);

Implementations

impl ContextTracker

pub fn new() -> Self

pub fn record_usage(&mut self, usage: &Usage, message_index: usize)

Record usage from an assistant response.

Call this after each assistant message to update the tracker with real token counts from the provider.

pub fn estimate_context_tokens(&self, messages: &[AgentMessage]) -> usize

Estimate current context size.

Uses real usage from the last assistant response as a baseline, then adds estimates (chars/4) for any messages added since. Falls back to pure estimation if no usage data is available.

pub fn reset(&mut self)

Reset tracking (e.g. after compaction replaces messages).

Trait Implementations

impl Default for ContextTracker

fn default() -> Self

Returns the “default value” for a type.