The ReAct Pattern

The foundational agent architecture

🔑 Key Concepts

How ReAct works — Reason (think about the task) → Act (call a tool) → Observe (see the result) → Reason again.
Implementation — LangChain's create_react_agent handles the prompt template and parsing. You provide tools and LLM.
Max iterations — Always set max_iterations (10-15). Unbounded agents loop forever and burn tokens.
Debugging — Verbose=True shows the thought trace. Essential for understanding why the agent made each decision.

💡 Practice: Try implementing each concept yourself before moving on. Reading about RAG and building RAG are very different things.