Your AI Agent Is a Demo Without a Harness

Added: 2026-05-24

[00:00:00]Your AI agent is not a product yet. The harness is what makes it win, and the harness is a product manager decision.

[00:00:05]So, what is harness? Here's a simple mental model. The model generates responses. The harness handles everything else. Think of the model as an engine. The harness is the car.

[00:00:14]Manifold, LangChain, and Vercel each spent thousands of engineering hours building agent harnesses. Manifold rewrote their harness five times in six months with the same model. The model is commodity. The harness is the moat.

[00:00:24]Three decisions need to be defined before any agent ships. Not by engineering, but by you. One, what triggers it? Two, what it can do without asking you? Three, what requires your approval before it acts? Every routing decision, every approval gate, every rollback trigger is yours. Most PMs describe what their agent does. AI PMs name the harness decision they own. Are you ready to make these three decisions for your agent product? If not, that's the gap to fill. Follow me to find out more about what's going on in the PM world. Like this video, so I know you want to learn more about the three harness decisions that every agent-first company will ask you. See you tomorrow.