ReAct is a way to organize an AI's work by alternating between reasoning about the task and taking an action, such as looking something up. The AI then uses what it observed to decide what to do next.
For example, if asked for a shop's opening hours, an AI might decide it needs current information, search an approved source, and use the result to answer.
The name combines “reasoning” and “acting.” This pattern can help an AI use information from tools, but it does not guarantee that its reasoning or the source it chose is correct.