TL;DR: A simple React or Next.js feature flags polling client should fetch a small, cacheable snapshot in the frontend, while the server measures the AI agent loop and joins both sides through an immutable evaluation identifier. For a logistics application, enable a rollout only when four invariants hold: one decision per evaluation, one stable assignment for the shipment workflow, one final usage record per agent run, and enough retained evidence to reconstruct why a cost landed in a cohort. Th...