Phase 8 — Fraud-Rule Simulation

[aaqib-hafeez-khan-in]

Parent epic: #3

Objective

Add configurable rule evaluation to simulate transaction screening without claiming to provide real fraud detection.

Scope

• Define a configurable rule-evaluation model.
• Support transaction-threshold rules.
• Support velocity checks.
• Support account restrictions.
• Record rule decisions and reasons.
• Integrate decisions with the transaction/audit trail.
• Add deterministic tests for allowed and blocked scenarios.

Acceptance criteria

• Rules are explicit, configurable, and independently testable.
• Rule decisions include actionable reasons.
• Rule evaluation does not mutate financial records incorrectly.
• Decisions are traceable to the originating transaction.

Out of scope

• Machine-learning fraud detection
• Real fraud-provider integration
• Claims of production fraud prevention

Delivery

Implement as a focused PR linked back to #3.