Definition · foundations
ReAct
ReAct is an agent pattern that puts thought, action, and observation steps in a loop. You can spot ReAct in practice when the record shows what the system observes, what choice it makes, and what changes next, without asking the reader to guess or trust a slogan.
157 definitions656 sourced recordsNamed source: ACL Anthology
Why does ReAct matter?
ReAct lets action results shape the next step. This can help when the path cannot be fixed in advance. For ReAct, start with three checks: What can the system observe? What choice can it make? What changes after it acts? The answers should point to visible evidence, not a promise.
What does ReAct look like?
An agent searches a name, reads the result, then changes its next query. This example makes ReAct visible by naming the actor, the action, and the result in practice. It is an illustration for readers, not a claim that every product behaves this way.
What is ReAct easy to confuse with?
ReAct alternates reasoning, action, and feedback. Plan-and-execute starts with a fuller plan. The closest entries here are RAG-style tool use, red teaming, chain of thought. Compare their definitions with ReAct before using the names as if they mean the same thing. That comparison keeps ReAct separate from nearby ideas without pretending the boundary is always perfect.
How certain is this definition?
This definition is provisional. ACL Anthology supports the version you see today, but a better or more direct source may change it. Open the cited page and check its date before you use this entry to choose a product, write a policy, set a safety control, or design a system.
Who introduced the term ReAct?
We have not verified who first introduced ReAct. The source supports a useful definition, but it may not be the earliest use. Until a dated primary record settles the question, we leave the origin open. A popular article or product page is not enough to name the person who coined a term.
What should you understand before ReAct?
Read artificial intelligence (AI) first when ReAct depends on a more basic idea or mechanism. The link gives you a useful route through the glossary. It does not mean every author teaches the subject in this order, so follow the source when the sequence matters.
What should this term help you answer?
Use ReAct to ask what an agent can observe, decide, change, remember, or hand off. The questions below turn the definition into a practical check. They are prompts for your own work, not claims made by the source, so change them to fit the system you are examining.
- What can the system observe?
- What choice can it make?
- What changes after it acts?
Which source supports this definition of ReAct?
ACL Anthology supports this working definition of ReAct. We checked the link on 2026-07-12. Open the original record for its context, methods, limits, and publication details. The short explanation here is a guide to ReAct; the linked source remains the evidence to inspect when the wording or boundary matters.
source foundReActChecked 2026-07-12→