What is ReAct (Reasoning + Acting) prompting, and why does interleaving thought and action help?
ReAct is the pattern behind most tool-using agents. What matters is why interleaving reasoning with actions (and observing results) beats reasoning alone or acting alone. Here is the answer that ties the prompt pattern to real agent behavior.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
ReAct is the pattern behind most tool-using agents. What matters is why interleaving reasoning with actions (and observing results) beats reasoning alone or acting alone. Here is the answer that ties the prompt pattern to real agent behavior.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.