3 · Tool-Calling & ReAct Loops

3. Autonomous Tool Calling & The ReAct Framework

Thought-Action-Observation loops, function schemas, and bounded execution graphs.

10 min read · 2 MCQs

The ReAct (Reasoning + Acting) Paradigm

Agents operate in a continuous cycle: 1. Thought (Model reasons about what it needs), 2. Action (Model emits a structured JSON tool call), 3. Observation (Application executes tool and feeds output back into prompt), 4. Repeat until task termination.

Deterministic Guardrails on Agent Loops

Autonomous loops can enter infinite recursion or take unintended destructive actions. Production agents require hard step limits (e.g. max 6 iterations), strict timeout budgets, idempotent tool designs, and human confirmation for irreversible state mutations.

Chapter quiz

2 questions · pass mark 75%

1. What are the core stages of the ReAct agent framework?
2. Why must agent tool-calling loops enforce strict step boundaries?