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ReAct (Reason + Act)
Reasoning and Acting
Phase 04 · Agentstechnique

An agent prompting pattern that alternates between explicit reasoning steps ('Thought') and tool actions ('Action').

Why it exists

Interleaving reasoning and acting enables agents to plan, evaluate intermediate tool outputs, and dynamically adapt execution paths.

How it works

Loops: 1) Thought: 'I should search for X', 2) Action: search(X), 3) Observation: Result text, 4) Thought: 'Now I can calculate...'.

Where you'll use this