Feedback Engineering: Where Agent Automation Gets Stuck, and for How Long

Z.ai published a postmortem on using a GLM-5.3-driven Infra Agent to deploy inference on a domestic chip cluster. The key insight: giving an agent only an end-to-end score traps it in blind guesswork. Splitting verification from diagnosis—with layered, fast, localizable feedback—lets the agent trace issues to specific code paths. Three real cases (precision loss, GIL contention, redundant kernel compute) show how diff comparisons, timeline traces, and micro-benchmarks guide root-cause analysis. End-to-end throughput reached ~3× baseline, but the vendor notes this combines multiple techniques and lacks an ablation study without diagnostic feedback. The engineer's role shifts to designing feedback environments, setting boundaries, and reviewing high-risk changes.