> What value does the middleman add?

I agree. Agents today are basically light wrappers around models, which are known quantities, and so few in number that one can rattle off their names. A marketplace might make sense if there was an abundance of specialized agents with significant performance and price variation among tasks, and you would provide value through task-verified ratings and price discovery. But this is not the case. Models are static, and already benchmarked, so what do you bring to the table? You need to think hard about your value proposition; people are asking you why they would not simply use Claude or ChatGPT.