Behaviors, decisions, execution: three layers of AI-safe engineering memory

TL;DR: AI-safe engineering needs three durable, machine-readable layers: a behavior layer (what the product must do), a decisions layer (why the team chose it), and an execution layer (what's actually running and whether it matches). Execution has mature tooling. Some domains have decision substrates: authority frozen into deterministic data. Most product teams don't have that kind of oracle, so the behavior layer is the empty one — and it's the layer that decides whether agents stay honest. Las