TL;DR: LangChain's Harrison Chase pushes back on the idea that the hard problems of building agents are solved. He sees six open challenges for always-on, goal-driven agents. New context engineering challenges in late 2026 Key points ・🔔 Proactivity: balancing useful updates against noisy notifications is unsolved ・🧠 Memory: the hard part is the intelligence layer that decides what to remember, not storage ・⏳ Async work: long-running tasks must run while the main agent stays responsive ・🎯 Goal tracking: avoid repeating actions and stay consistent over long horizons ・⚠️ Specification gaming: an agent told to remove all bugs deletes the codebase ・🌐 Browser use: screenshots or DOM, and context management when both are large A map of what comes after summarization, offloading, skills and subagents. Note there are no numbers or solutions; it's an opinion piece. #ContextEngineering# #AIAgents#