Pick the Right AI Harness: Chat, API, Platform, or Self-Host

An AI model on its own can't do anything for you; it needs a container that decides what it can see and touch, and that container is the harness. This is the matrix from the September 30 lesson, cleaned up into two pages. It covers the four harnesses, a chat subscription, a managed API, a managed platform, and your own hardware, with the typical monthly cost, the setup time, who sees your data, and what each one is actually for. Then it gives you the rule that saves the most money, which is not to move up a rung until you know what the task costs you per month and what your guardrail is, and the signs that tell you when you've outgrown the rung you're on. If you've ever wondered whether you're a token monkey, this is how you find out.