Struct TokenBudgetGuard 

pub struct TokenBudgetGuard { /* private fields */ }

Guards LLM requests against token over-spend.

TokenBudgetGuard is Clone + Send + Sync. All clones share the same budget counters via an Arc.

Implementations

impl TokenBudgetGuard

pub fn new(config: TokenBudgetConfig) -> Self

Create a new guard with the given configuration.

pub fn check(&self, text: &str) -> Result<u64, TokenBudgetError>

Check whether text fits within the budget limits.

If the check passes, the estimated token count is reserved against the period budget. Call release with the actual token count from the provider response to correct the reservation.

Returns

• Ok(estimated_tokens) — request is within budget; proceed to LLM.
• Err(TokenBudgetError::*) — budget exceeded; reject the request.

pub fn release(&self, estimated: u64, actual: u64)

Adjust the period budget by the difference between the estimated and actual token counts returned by the provider.

Call this after receiving the LLM response with the real token count. If actual < estimated, the surplus is credited back. If actual > estimated (rare for input tokens), the overage is debited.

pub fn total_tokens_estimated(&self) -> u64

Total tokens estimated across all requests since creation (lifetime).

pub fn period_tokens_used(&self) -> u64

Tokens consumed in the current rolling period window.

pub fn period_tokens_remaining(&self) -> u64

Remaining token budget in the current period.

pub fn period_utilization(&self) -> f64

Fraction of the period budget consumed (0.0 = empty, 1.0 = exhausted).

pub fn requests_allowed(&self) -> u64

Number of requests allowed through the budget gate.

pub fn requests_rejected(&self) -> u64

Number of requests rejected by the budget gate.

pub fn rejection_rate(&self) -> f64

Budget rejection rate: rejected / (allowed + rejected).

Trait Implementations

impl Clone for TokenBudgetGuard

fn clone(&self) -> TokenBudgetGuard

Returns a duplicate of the value.

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

Performs copy-assignment from source.