In February 2026, Mitchell Hashimoto (co-founder of HashiCorp) described his habit of engineering permanent fixes into an AI agent's environment whenever it made a mistake. He called it "engineering the harness." Days later, OpenAI formalized the concept in a blog post. Around the same time, without having read either, I wrote my first enforcement hook for a production AI system. Different continent, different scale, different context. Same problem. A few weeks later, Birgitta Bockeler formalized it on Martin Fowler's site . Red Hat published their version. LangChain. Salesforce. By April, the term was everywhere. I didn't discover any of this until recently. I was too busy building the thing they were naming. That's not a flex. It's something more interesting. When engineers face the same constraints (unreliable model outputs, production stakes, context that evaporates), they converge on the same solutions. Different trails, same summit.…