The difference was that one of them builds software the way it gets built now, and the other had not noticed it changed. Nobody sent a memo. Agent orchestration and harnesses just stopped being the advanced move and became the floor, quietly, one team at a time. Most leaders are still treating that as a personal preference, settled engineer by engineer.
I wrote The New Way to Build Software for the person who has to make the call for a whole team. There is no prompt pack here and no manifesto. It is a working account of what actually changed, and a plan for moving a real team onto the new default without betting the quarter on a vibe.
Senior engineers, tech leads, and engineering managers who can already ship and now have to decide how everyone else builds. If you are the one who has to stand in front of the team and say this is how we build now, I wrote this for you.
Wes Halloran writes practical books for working developers and engineering leaders making the shift to AI-agent development. He writes about how the tools actually behave once the demo ends, and he does not accept a green light he did not check. This book comes out of watching team after team stall on the same two questions: who owns the harness, and how far do you let the agent run.
Part of the AI and Agentic Engineering series.