ReAct Pattern
An agent design that interleaves explicit reasoning with actions, one step at a time.
ReAct — reason plus act — has the model state its thinking, take one action, read the observation, and think again. Alternating the two beats reasoning everything upfront because real environments return surprises. Most agent frameworks implement some version of it.
In practice: Thought: I need the invoice date. Action: search_invoices. Observation: three results. Thought: pick the most recent.