Relay: AI assistant with a hard spend cap

Brief: put OpenAI/Claude into a product without surprise bills. What I made: a tool-calling assistant with answer caching, a hard monthly spend cap, request logging, and a small dashboard that shows latency and cache hit rate. Result: predictable cost per month, repeated questions answered from cache at zero API cost, and the team can see exactly what the model is spending. Stack: Python, OpenAI and Claude APIs, FastAPI, React.