4 user stories: alert investigation (P1), transaction ingestion + rule engine (P1), rule management (P2), dashboard (P3). 16 functional requirements, 7 success criteria, 5 entities. Quality checklist: all 16 items passed.
6 core principles: Security-First, Explainability, Test-First, Observability, Data Privacy by Design, Simplicity (YAGNI). Includes Security & Compliance, Development Workflow, and Governance sections.