chio-underwriting

chio-underwriting defines Chio's underwriting decision, simulation, and appeal contracts: the risk taxonomy and reason codes, evidence references (receipt, reputation, certification, runtime assurance, settlement, metered billing), a fail-closed decision evaluator, a deterministic insurance-premium pricing formula, and reputation-tiered marketplace credit limits. It builds on chio-appraisal and is consumed by chio-market, chio-credit, chio-kernel, and chio-cli.

The crate is pure data and decision logic: no I/O, no runtime state, and #![forbid(unsafe_code)]. It does not depend on chio-kernel; callers supply kernel-derived inputs (compliance score, behavioral-anomaly score) themselves so the crate graph (chio-kernel -> chio-market -> chio-underwriting) stays directed.

Responsibilities

• Defines the risk taxonomy, reason codes, and evidence-reference contracts (UnderwritingRiskClass, UnderwritingReasonCode, UnderwritingRiskTaxonomy, UnderwritingEvidenceReference).
• Evaluates a UnderwritingPolicyInput against a UnderwritingDecisionPolicy and produces a fail-closed decision report and signed artifact (evaluate_underwriting_policy_input, build_underwriting_decision_artifact).
• Prices insurance premiums deterministically from a compliance score and optional behavioral-anomaly signal (price_premium).
• Computes reputation-tiered marketplace credit limits with fail-closed revocation gating (compute_marketplace_credit_limit).
• Defines the appeal wire contracts and decision query/list/simulation report schemas; it does not implement appeal state transitions or a simulation runner (see ARCHITECTURE.md).

Public API

Re-exported: appraisal (= chio-appraisal); canonical, capability, crypto, receipt (from chio-core-types).

From decision:

• evaluate_underwriting_policy_input, build_underwriting_decision_artifact
  • evaluate a UnderwritingPolicyInput and build a SignedUnderwritingDecision.
• UnderwritingDecisionPolicy, UnderwritingDecisionReport, UnderwritingDecisionFinding, UnderwritingDecisionArtifact, UnderwritingBudgetRecommendation, UnderwritingPremiumQuote - policy, evaluation output, and derived artifact fields.
• UnderwritingDecisionQuery, UnderwritingDecisionListReport, UnderwritingSimulationRequest, UnderwritingSimulationReport - query, listing, and simulation schemas.

From premium:

• price_premium, risk_multiplier - the pricing formula.
• PremiumInputs, PremiumQuote, LookbackWindow, PremiumDeclineReason.

From marketplace_limits:

• compute_marketplace_credit_limit, MarketplaceCreditLimitRequest, MarketplaceCreditLimitDecision, MarketplaceLimitTier.

From the crate root: UnderwritingPolicyInput, UnderwritingPolicyInputQuery, evidence types (UnderwritingReceiptEvidence, UnderwritingReputationEvidence, UnderwritingCertificationEvidence, UnderwritingRuntimeAssuranceEvidence, UnderwritingComplianceEvidence), and appeal contracts (UnderwritingAppealRecord, UnderwritingAppealCreateRequest, UnderwritingAppealResolveRequest).

Usage

use chio_underwriting::{price_premium, LookbackWindow, PremiumInputs, PremiumQuote};

let window = LookbackWindow::new(1_700_000_000, 1_700_003_600).expect("valid lookback window");
let inputs = PremiumInputs::new(Some(820), None, 1_000, "USD");

match price_premium("agent-7", "tool:exec", window, &inputs) {
    PremiumQuote::Quoted { quoted_cents, .. } => println!("premium: {quoted_cents} cents"),
    PremiumQuote::Declined { reason, .. } => println!("declined: {reason:?}"),
}

Testing

cargo test -p chio-underwriting

See also

• chio-appraisal - supplies the attestation-verifier-family taxonomy embedded in UnderwritingRuntimeAssuranceEvidence.
• chio-market - calls price_premium in its insurance flow and binds quotes into policies.
• chio-credit - re-exports this crate as underwriting and consumes its certification and compliance-evidence types for risk reports.
• chio-kernel - consumes decision list/outcome types for operator reporting and is the intended source of PremiumInputs.compliance_score.
• chio-cli - calls compute_marketplace_credit_limit to gate chio guard market install by tenant tier and revocation.
• chio-core - re-exports this crate as chio_core::underwriting in the unified protocol facade.