Build vs. Buy for Agent Harnesses: The Real Question

A thread on the CTO Lunches mailing list a few weeks ago. One of the members opened it: "Like many of you, I see trends converging and am struggling to navigate the build vs buy decisions and identify where or when it makes sense to build a bespoke approach (with the attendant maintenance and support) and when to bet on third-party / managed 'service'-ish approaches." The organizer of the group responded: "Your question is the question everyone is asking. And I'm not seeing folks deciding yet." Another participant, after sharing his approach in detail, concluded: "I think you can get a good chunk of the benefit building incrementally and owning your context and it substantially reduces the 'pick the right one' problem which to me feels unsolvable right now." Fourteen messages. No consensus. I've been in that conversation myself, not in the thread but in practice, building a product where the build vs. buy question came up repeatedly. Here's what I learned. The Pain We Actually Had We w