Is harness engineering dead? Absolutely NOT! Like the "prompt engineering is dead" and "RAG is dead" claims, this is just another misinformed claim used for clicks and ragebaiting. Mostly, it stems from a few recently published papers with poor experimental setups that focus only on SWE on already benchmaxxed SWE benchmarks. If we are talking about SWE, of course a lot of the harness stuff is getting absorbed by the model. And that's great. Thanks to better approaches for co-evolving harnesses and models. But in reality, you still need a stable, minimal harness to get high-quality results reliably and affordably. The big issue I see is that we assume SWE won't evolve. It already has, and as a result, teams are finding they need specialized harnesses to improve code review, cybersecurity, and work in more complex environments (multi-agent systems, sandboxes, etc.). The harness isn't just about prompts; it's the scaffolding that makes AI models work in the real world, covering security, safety guardrails, authorization, coordination, memory, scalable and new infra, efficiency, costs, and more. If you have been in computer science for long, none of these stay fixed. So how can anyone claim the scaffold/harness isn't needed? And worse, how can anyone claim these AI models will know all that, much of it proprietary and custom to every problem and domain? It gets more complex when you apply agents beyond SWE; domain-specific harnesses are popping up everywhere. These require entirely new ways to optimize context, memory, guardrails, security, and more. To make my point even clearer, look at the new wave of proactive and personal agents (Muse, Grok Bot, dots, Instinct, etc.). They involve clever, complex harness engineering. I think we will see vertical personal agents too, so the harness will get even more specialized. I can go on and on. I'd love to hear what other serious builders here are seeing.