How would you isolate tenants and control spend on a shared managed AI platform?

I define which platform quotas are global, regional, model-specific, or resource-specific and translate them into enforceable application budgets. A shared gateway preserves tenant claims and cannot be tricked into billing or retrieving for another tenant. Hard spend ceilings have a deliberate degraded response instead of silently failing all customers. Capacity and fallback plans model correlated tenant bursts. Isolation tests cover caches, traces, managed knowledge bases, agent state, and administrative views as well as the main inference request.