I built a 200 line AI router in TypeScript. My monthly bill dropped 41%.

I track my own AI spend across three projects. In March, the line item that grew fastest was not Claude or GPT calls. It was my Cursor seat plus my Copilot seat plus the Anthropic API I was hitting from a personal CLI. Three subscriptions, three meters, and the same Opus tokens billed twice because Cursor was sending the same context to its own backend that I was already passing through to Anthropic directly. The wrappers do not advertise this. The router code is not their product. The product i