The harness matters more than the model

When my agent produces bad output, I don't switch models. I open a markdown file. I don't comparison-shop. ChatGPT might be better than Claude this week — I genuinely don't know, because checking would cost me more than it would earn me. Same with Gemini, same with whatever ships next quarter. Here's why I think the model question is mostly a distraction. In my experience, output quality is maybe…