ReAct Agents Explained: Concepts & Practical Uses

This post explains the ReAct agent pattern, detailing its reasoning-and-acting loop (Thought, Action, Observation, Repeat/Finish). It contrasts ReAct with Plan-and-execute and Reflexion patterns, and describes three tiers of context management: prompt, thread-scoped persistence, and cross-thread long-term memory. The post also discusses practical uses in customer support and coding agents, and analyzes the performance and cost challenges of growing context windows in production, including context poisoning, distraction, confusion, and clash.