Model selection is the new dependency pinning. You would not add a library to your lockfile because a blog post praised it; you would run its tests against your own code first. Most teams do the opposite with AI models: they pick one from a trending article, configure it once, and never re-score it. A 20-prompt harness turns that decision back into evidence. Here is the concrete situation I am working from. MonkeyCode is an open-source project whose free tier, at the time of writing, includes...