Struct SessionTracker 

pub struct SessionTracker {
    pub model: String,
    pub turns: Vec<TurnUsage>,
}

Accumulates token usage across all turns of a single agent session.

The tracker is owned by CoderAgent::run() for the duration of a task. At the end of the task it is embedded in AgentResult so the REPL can display the final totals and store them in SQLite.

Example

let mut tracker = SessionTracker::new("gpt-4o".to_string());
tracker.record(Some(&Usage { prompt_tokens: 100, completion_tokens: 50, total_tokens: 150 }));
assert_eq!(tracker.total_prompt_tokens(), 100);
assert_eq!(tracker.total_completion_tokens(), 50);

Fields

model: String

Name of the model in use (used for cost lookup).

turns: Vec<TurnUsage>

Ordered list of per-turn records (earliest first).

Implementations

impl SessionTracker

pub fn new(model: impl Into<String>) -> Self

Create a new empty tracker for model.

pub fn record(&mut self, usage: Option<&Usage>)

Record the usage from one LLM call.

If the API returned no usage data (None) the turn is silently skipped — we never panic or error on missing usage.

pub fn total_prompt_tokens(&self) -> u32

Sum of all prompt tokens across every turn.

pub fn total_completion_tokens(&self) -> u32

Sum of all completion tokens across every turn.

pub fn total_tokens(&self) -> u32

Grand total tokens (prompt + completion).

pub fn turn_count(&self) -> usize

Number of turns recorded.

pub fn estimated_cost_usd(&self) -> Option<f64>

Estimate cost in USD using the built-in price table.

Returns None when the model isn’t found in the table. Prices are per 1,000,000 tokens (as published by the providers).

pub fn summary_line(&self) -> String

Format a short one-line summary suitable for the completion banner.

Example: 15,678 tokens (~$0.047) If no turns were recorded (provider didn’t return usage), returns "".

pub fn detailed_report(&self) -> String

Format a detailed multi-line report for the /tokens REPL command.

Shows per-turn breakdown plus session totals and cost estimate.

Trait Implementations

impl Clone for SessionTracker

fn clone(&self) -> SessionTracker

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SessionTracker

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

Formats the value using the given formatter.