Beyond the Chat Window: How to Build AI Agents That Run for Weeks

As AI agents scale beyond single-session interactions, the engineering challenge shifts from model capability to harness architecture—managing persistent state, session continuity, and external memory across days or weeks of autonomous execution. Major platforms including Anthropic, Google, and Cursor are converging on identical architectural principles: separating model loops, execution sandboxes, and event logs, with specialized roles for planning, generation, and evaluation. This convergence signals that multi-day autonomous agents are becoming the de facto standard for enterprise AI automation.