This architecture is designed as a cost-optimized, intelligent AI inference gateway on AWS that dynamically routes requests to the most appropriate foundation model while maintaining low latency and operational efficiency. Incoming requests enter through Amazon API Gateway and are forwarded to a Lambda-based Router that performs request validation, normalization, and workload classification. A Token Optimizer reduces prompt size and removes unnecessary context before execution, minimizing model costs. The Model Selector Lambda acts as the decision engine, leveraging a Semantic Cache in DynamoDB to immediately serve previously answered or semantically similar requests and consulting CloudWatch metrics for real-time performance, latency, and utilization insights. Based on request complexity, cost targets, and response quality requirements, the selector routes traffic to the optimal model tier—Small (Claude Instant) for simple low-latency tasks, Medium (Claude 2) for balanced workloads, or Large (Claude 3) for complex reasoning. This multi-model orchestration pattern significantly reduces inference costs, improves response times, increases cache hit rates, and provides centralized observability, making it a scalable and production-ready architecture for enterprise generative AI workloads on AWS.