Building a local-first AI router, and doing the honest math on what it saves. AI disclosure: I built this project with an AI coding assistant (Claude), which also helped draft this article. The benchmark ran on my own laptop, and I have checked every number, source and claim below against the code and the raw results, which are all public. Every AI feature you use, a chatbot, a writing assistant, a "summarize this" button, sends your request to a data center. Even when the reques...