'Loop Engineering' Crystallizes Into Four Canonical Agent Loops: Heartbeat, Cron, Hook, Goal

MarkTechPost·medium signal

The mid-2026 'loop engineering' discourse — replacing yourself as the person who prompts the agent — converged this week on a four-type taxonomy: heartbeat loops (run continuously on a short interval), cron loops (scheduled), hook loops (event-triggered by a PR push or CI failure), and goal loops (iterate until a success condition, then stop). A July 12 MarkTechPost guide ties the pattern to Karpathy's viral 'autoresearch' repo (~90K stars), and a high-engagement X thread on 'the four types of agent loops' (227K views) pushed it into the timeline. For builders, the shift is from hand-writing prompts to designing the loops that prompt the agent — directly relevant to cron-driven research pipelines.