Struct PolicySnapshot 

pub struct PolicySnapshot {
    pub policy_epoch: u64,
    pub catalog_epoch: u64,
    pub hard_risk_limit_bps: u16,
    pub minimum_confidence_bps: u16,
    pub risk_penalty_multiplier_bps: u16,
    pub latency_penalty_microunits_per_ms: u64,
    /* private fields */
}

An immutable snapshot of the decision policy and model catalog.

Create with PolicySnapshot::try_new (validated) or PolicySnapshot::new_unchecked, then call prescribe for each request. The snapshot is Clone and can be shared across threads via Arc.

Fields

policy_epoch: u64

catalog_epoch: u64

hard_risk_limit_bps: u16

minimum_confidence_bps: u16

risk_penalty_multiplier_bps: u16

latency_penalty_microunits_per_ms: u64

Implementations

impl PolicySnapshot

pub fn new_unchecked( policy_epoch: u64, catalog_epoch: u64, hard_risk_limit_bps: u16, minimum_confidence_bps: u16, risk_penalty_multiplier_bps: u16, latency_penalty_microunits_per_ms: u64, models: Vec<KernelModel>, ) -> Self

Creates a policy snapshot without validation (escape hatch).

Production guidance

Use try_new for any policy served to real traffic. new_unchecked is for unit tests, fuzz fixtures, and experiments where you call validate yourself or intentionally construct invalid catalogs.

Serving from an unchecked snapshot without a successful validate() is an audit failure.

pub fn new( policy_epoch: u64, catalog_epoch: u64, hard_risk_limit_bps: u16, minimum_confidence_bps: u16, risk_penalty_multiplier_bps: u16, latency_penalty_microunits_per_ms: u64, models: Vec<KernelModel>, ) -> Self

👎Deprecated since 0.3.9:

use PolicySnapshot::try_new for validated snapshots or new_unchecked for tests

Creates a new policy snapshot from a model catalog (alias for new_unchecked).

pub fn models(&self) -> &[KernelModel]

Returns the model catalog.

pub fn validate(&self) -> Result<(), PolicyError>

Validate catalog and basis-point invariants before serving traffic.

pub fn try_new( policy_epoch: u64, catalog_epoch: u64, hard_risk_limit_bps: u16, minimum_confidence_bps: u16, risk_penalty_multiplier_bps: u16, latency_penalty_microunits_per_ms: u64, models: Vec<KernelModel>, ) -> Result<Self, PolicyError>

Build a snapshot and validate the catalog.

pub fn prescribe_batch(&self, inputs: &[KernelInput]) -> Vec<KernelDecision>

Evaluate many inputs. Allocates the output vector only.

pub fn prescribe_with_trace( &self, input: KernelInput, ) -> (KernelDecision, DecisionTrace)

Evaluate input and return decision plus rejection histogram.

pub fn prescribe(&self, input: KernelInput) -> KernelDecision

Evaluate input against the policy and return the optimal decision.

The kernel checks 11 constraint gates per candidate, computes utility as quality_adjusted_value - risk_penalty - cost - latency_penalty, and selects the candidate with the highest positive utility.

If no candidate has positive utility, the request is rejected (fail-closed). The decision also records the counterfactual (second-best) candidate.

This function does not allocate.

pub fn utility_for_model( &self, input: KernelInput, model_id: u32, ) -> Option<i64>

Evaluate utility for a specific catalog model if it passes all constraint gates.

Unlike prescribe, this does not rank candidates — it only answers whether model_id is eligible and what its utility would be.

Trait Implementations

impl Clone for PolicySnapshot

fn clone(&self) -> PolicySnapshot

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PolicySnapshot

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

Formats the value using the given formatter.