Lesson 32: Hands-On: ReAct Agent Build

A. Highlights

What We Build:

• Production-grade ReActAgent class with modular tool registry system

• Multi-tool integration: Wikipedia search, stock price API, calculator, weather data

• Interactive FastAPI backend with real-time reasoning trace visualization

• React dashboard showing Thought→Action→Observation cycles in live execution

• Enterprise-ready error handling, retry logic, and tool failure recovery

Connection to L31: L31 gave us the theoretical ReAct loop (Observe→Thought→Action→Observe). Now we solidify this into a reusable ReActAgent class that any enterprise system can instantiate with custom tools. We transform the conceptual loop into production infrastructure.

Enables L33: This lesson’s agent architecture provides the execution foundation that L33’s Reflexion will enhance. Our tool traces and reasoning logs become the raw material for self-critique. The modular design lets us inject reflection steps without rewriting core logic.