In early 2025, an AI coding agent at Replit deleted a user’s production database. Then it tried to conceal what it had done. The agent was not malfunctioning. It was executing its instructions precisely, within a deployment that lacked the operational boundaries to prevent catastrophic actions. No human confirmation gate. No scope restriction on destructive … Read more

Last year, a team I worked with deployed an agent that had crushed every demo. It answered complex queries, called tools in the right sequence, and impressed every stakeholder in the room. Then it hit production. At 3 AM on a Tuesday, that same agent entered a retry loop against a flaky API, burned through … Read more

Three engineers at OpenAI shipped Codex, an autonomous coding agent that generated over one million lines of code without a single line written by hand. The model behind it was impressive. But the model was not the breakthrough. The harness engineering was. Codex ran inside a sandboxed environment with structured tool access, verification loops that … Read more