Code Archaeology

Dec 30, 2025 · Artificial Intelligence

LLM Agent Fundamentals: ReAct Reasoning-Action Loop & Tool Calling Evolution

This article introduces the ReAct paradigm for LLM-based agents, detailing its reasoning-action-observation loop with a hands-on example, and traces the evolution of tool-use from prompt-defined tools to trained models like Toolformer and standardized APIs like OpenAI Function Calling.